Allowed the boot script to check multiple names for the chez executable.

JOLT_TRACE: map tail-frame history to ns/name (file:line)

.github/workflows/release.yml

@@ -12,6 +12,7 @@ on:
   push:
     tags:
       - 'v*'
+  workflow_dispatch: {}   # dry-run the build matrix without tagging
 
 permissions:
   contents: write   # create/update the GitHub Release and upload assets
@@ -26,10 +27,18 @@ jobs:
         include:
           - os: ubuntu-latest
             target: x86_64-linux
+            shell: bash
           # No x86_64-macos: GitHub is retiring the macos-13 Intel runner (jobs
           # queue forever). Intel Macs build from source. macos-14 is arm64.
           - os: macos-14
             target: aarch64-macos
+            shell: bash
+          - os: windows-latest
+            target: x86_64-windows
+            shell: msys2 {0}
+    defaults:
+      run:
+        shell: ${{ matrix.shell }}
     steps:
       - uses: actions/checkout@v5
         with:
@@ -78,6 +87,65 @@ jobs:
         if: runner.os == 'macOS'
         run: brew install chezscheme lz4
 
+      # --- Windows: MSYS2/MinGW-w64 toolchain + Chez built from source (ta6nt).
+      # The whole job runs in the msys2 shell so cc/xxd/paths behave; the
+      # produced joltc.exe is a plain Windows binary (no MSYS runtime dep). ---
+      - name: Set up MSYS2 (Windows)
+        if: runner.os == 'Windows'
+        uses: msys2/setup-msys2@v2
+        with:
+          msystem: MINGW64
+          update: false
+          # inherit the runner PATH so GITHUB_PATH additions (the chez wrapper
+          # dir) are visible inside the msys2 shell
+          path-type: inherit
+          install: >-
+            git make vim unzip zip
+            mingw-w64-x86_64-gcc
+            mingw-w64-x86_64-lz4
+            mingw-w64-x86_64-zlib
+            mingw-w64-x86_64-ntldd
+
+      - name: Cache Chez Scheme (Windows)
+        if: runner.os == 'Windows'
+        id: cache-chez-win
+        uses: actions/cache@v4
+        with:
+          path: chez-install
+          key: chez-${{ runner.os }}-v10.4.1-mingw64
+
+      - name: Build Chez Scheme from source (Windows)
+        if: runner.os == 'Windows' && steps.cache-chez-win.outputs.cache-hit != 'true'
+        run: |
+          git clone --depth 1 --branch v10.4.1 https://github.com/cisco/ChezScheme.git /tmp/chez-src
+          cd /tmp/chez-src
+          ./configure --threads
+          make -j"$(nproc)"
+          # `make install` drives the unix installsh through cmd and dies; the
+          # build tree has everything — assemble the layout by hand. Boot files
+          # sit next to scheme.exe (that's where the Windows kernel looks).
+          inst="$GITHUB_WORKSPACE/chez-install"
+          mkdir -p "$inst/bin" "$inst/csv"
+          cp ta6nt/bin/ta6nt/*.exe "$inst/bin/"
+          cp ta6nt/bin/ta6nt/*.dll "$inst/bin/" 2>/dev/null || true
+          cp ta6nt/boot/ta6nt/petite.boot ta6nt/boot/ta6nt/scheme.boot "$inst/bin/"
+          cp ta6nt/boot/ta6nt/petite.boot ta6nt/boot/ta6nt/scheme.boot "$inst/csv/"
+          cp ta6nt/boot/ta6nt/scheme.h "$inst/csv/"
+          cp ta6nt/boot/ta6nt/equates.h "$inst/csv/" 2>/dev/null || true
+          cp ta6nt/boot/ta6nt/libkernel.a "$inst/csv/" || { echo "libkernel.a not found:"; find ta6nt -name "*.a" -o -name "kernel*"; exit 1; }
+
+      - name: Put chez on PATH (Windows)
+        if: runner.os == 'Windows'
+        run: |
+          bindir="$GITHUB_WORKSPACE/chez-install/bin"
+          { echo '#!/bin/sh'; echo "exec \"$bindir/scheme.exe\" \"\$@\""; } > "$bindir/chez"
+          chmod +x "$bindir/chez"
+          echo "$bindir" >> "$GITHUB_PATH"
+          echo "JOLT_CHEZ_CSV=$GITHUB_WORKSPACE/chez-install/csv" >> "$GITHUB_ENV"
+          # cc is the build's compiler name; alias it to mingw gcc
+          { echo '#!/bin/sh'; echo 'exec gcc "$@"'; } > "$bindir/cc"
+          chmod +x "$bindir/cc"
+
       - name: Show Chez version
         run: chez --version
 
@@ -86,6 +154,19 @@ jobs:
       # dev-machine check — see jolt-8479). `make joltc-release`, not `make joltc`.
       - name: Build joltc (release)
         run: make joltc-release
+        env:
+          # Bake the release tag into the binary (build-joltc falls back to
+          # `git describe` when this is empty, e.g. a workflow_dispatch dry run).
+          JOLT_VERSION: ${{ startsWith(github.ref, 'refs/tags/') && github.ref_name || '' }}
+
+      - name: Inspect the binary (Windows)
+        if: runner.os == 'Windows'
+        run: |
+          set +e
+          ls -la target/release/
+          ntldd target/release/joltc.exe 2>&1 | head -20
+          ./target/release/joltc.exe -e '(+ 1 2)'
+          echo "exit=$?"
 
       # Sanity: the built binary runs (no Chez needed) and self-reports a value.
       - name: Smoke the binary
@@ -132,16 +213,24 @@ jobs:
           ver="${GITHUB_REF_NAME}"
           name="joltc-${ver}-${{ matrix.target }}"
           mkdir -p "dist/${name}"
-          cp target/release/joltc "dist/${name}/joltc"
           cp README.md LICENSE "dist/${name}/"
-          tar -C dist -czf "dist/${name}.tar.gz" "${name}"
-          ( cd dist && shasum -a 256 "${name}.tar.gz" > "${name}.tar.gz.sha256" )
+          if [ "${{ runner.os }}" = "Windows" ]; then
+            cp target/release/joltc.exe "dist/${name}/joltc.exe"
+            ( cd dist && zip -r "${name}.zip" "${name}" && sha256sum "${name}.zip" > "${name}.zip.sha256" )
+          else
+            cp target/release/joltc "dist/${name}/joltc"
+            tar -C dist -czf "dist/${name}.tar.gz" "${name}"
+            ( cd dist && shasum -a 256 "${name}.tar.gz" > "${name}.tar.gz.sha256" )
+          fi
           ls -la dist
 
       - name: Upload to the GitHub Release
+        if: startsWith(github.ref, 'refs/tags/')
         uses: softprops/action-gh-release@v2
         with:
           files: |
             dist/*.tar.gz
             dist/*.tar.gz.sha256
-          fail_on_unmatched_files: true
+            dist/*.zip
+            dist/*.zip.sha256
+          fail_on_unmatched_files: false

.github/workflows/tests.yml

@@ -56,7 +56,11 @@ jobs:
       - name: Install JDK + Clojure (certify oracle)
         run: |
           sudo apt-get install -y default-jdk rlwrap
-          curl -L -O https://github.com/clojure/brew-install/releases/latest/download/linux-install.sh
+          # --retry + --fail so a transient CDN error retries instead of handing
+          # bash an HTML error page (a 2min timeout page flaked a run)
+          curl --fail --retry 5 --retry-delay 10 --retry-all-errors -L -O \
+            https://github.com/clojure/brew-install/releases/latest/download/linux-install.sh
+          head -1 linux-install.sh | grep -q '^#!' || { echo "installer download corrupt"; cat linux-install.sh | head -5; exit 1; }
           sudo bash linux-install.sh
           clojure --version
 

Makefile

@@ -4,18 +4,23 @@
 # build step. `make test` is the full gate. `make remint` rebuilds the seed after a
 # source change.
 
-.PHONY: test ci values corpus unit smoke buildsmoke staticnativesmoke selfhost sci cts certify ffi transient infer wp devirt fieldread numwp fieldnum protoret narrow directlink numeric inline shakesmoke remint joltc joltc-release joltc-debug joltcsmoke
+.PHONY: test ci values corpus unit smoke buildsmoke staticnativesmoke selfhost sci cts certify ffi transient infer wp devirt fieldread numwp fieldnum protoret narrow directlink numeric inline shakesmoke remint joltc joltc-release joltc-debug joltcsmoke submodules
+
+# Every target needs the vendored submodules; fail with the fix, not a load error.
+submodules:
+	@test -f vendor/irregex/irregex.scm || { \
+	  echo "vendor submodules missing; run: git submodule update --init --recursive"; exit 1; }
 
 # Full gate (dev machine). Includes the self-host byte-fixpoint, which only holds
 # on the same Chez that minted the seed.
-test: selfhost ci
+test: submodules selfhost ci
 	@echo "OK: all gates passed"
 
 # CI gate: behavior only. The checked-in seed is a minted artifact (like a
 # lockfile) — it RUNS correctly on any Chez, but `selfhost` rebuilds it and a
 # different Chez version may emit byte-different (gensym/order) output, so the
 # byte-fixpoint is a dev-machine check, not a CI one (jolt-8479).
-ci: values corpus unit smoke buildsmoke staticnativesmoke sci cts ffi transient infer wp devirt fieldread numwp fieldnum protoret narrow directlink numeric inline certify
+ci: submodules values corpus unit smoke buildsmoke staticnativesmoke sci cts ffi transient infer wp devirt fieldread numwp fieldnum protoret narrow directlink numeric inline certify
 	@echo "OK: CI gates passed"
 
 # Self-host fixpoint: bootstrap.ss rebuild == checked-in seed.

README.md

@@ -9,8 +9,12 @@ runs it on Chez. The compiler is self-hosted: it is written in Clojure
 
 ## Install
 
-Grab the self-contained `joltc` binary (Linux/macOS) — it bundles the runtime,
-compiler, and standard library, so there is nothing else to install.
+Grab the self-contained `joltc` binary (Linux/macOS/Windows) — it bundles the
+runtime, compiler, and standard library, so there is nothing else to install.
+Download the binary archive for your platform from the
+[releases page](https://github.com/jolt-lang/jolt/releases) (`joltc-<ver>-<platform>.tar.gz`,
+or the `.zip` on Windows). The "Source code" archives GitHub attaches to every
+release are not binaries — see [Build](#build) before using one.
 
 With Homebrew:
 
@@ -45,6 +49,18 @@ cd jolt
 bin/joltc -e '(+ 1 2)'        # => 3
 ```
 
+The `--recurse-submodules` matters: jolt vendors its regex engine and test
+suites as git submodules. In a checkout that's missing them (a plain
+`git clone`, or after pulling a commit that adds one), fetch them with:
+
+```bash
+git submodule update --init --recursive
+```
+
+Note that GitHub's auto-generated "Source code (zip/tar.gz)" archives on the
+releases page do **not** contain submodules, so they can't run or build —
+clone the repo instead (or grab a prebuilt binary from the same page).
+
 After changing a compiler source — the reader (`host/chez/reader.ss`), the
 analyzer/IR/backend (`jolt-core/jolt/*.clj`), or the `clojure.core` overlay
 (`jolt-core/clojure/core/*.clj`) — re-mint the seed:

bin/joltc

@@ -14,5 +14,28 @@
 # JOLT_PWD.
 root="$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)"
 export JOLT_PWD="${JOLT_PWD:-$PWD}"
+
+# Identify the Chez Scheme executable
+while read -r CHEZ
+do
+    if [ `which ${CHEZ}` ]
+    then
+	break;
+    fi
+done <<EOF
+chez
+chezscheme
+EOF
+
+# If we failed to find one, whinge and exit.
+if [ ! `which ${CHEZ}` ]
+then
+    echo "No valid Chez Scheme executable found: please install Chez Scheme."
+    exit 1
+fi
+
+# Version for --version / banners: git describe of this checkout, else "dev".
+export JOLT_VERSION="${JOLT_VERSION:-$(git -C "$root" describe --tags --always --dirty 2>/dev/null || echo dev)}"
 cd "$root" || exit 1
-exec chez --script host/chez/cli.ss "$@"
+exec ${CHEZ} --script host/chez/cli.ss "$@"
+

docs/tools-deps.md

@@ -182,6 +182,30 @@ a root, transitively.
 - Source only; compiled `.class` files in a git dep are ignored.
 - git `:git/sha` must be a full SHA (`git fetch` can't resolve a short one).
 
+## Stack traces
+
+An uncaught error prints the message, the top-level source location, and — when
+frames are available — a `trace:` backtrace. In an AOT `jolt build --direct-link`
+binary the frames map to `ns/name (file:line)`; on the runtime eval path they are
+the surviving fn names. Tail-call optimization erases tail-called frames, so the
+default trace shows only the non-tail spine.
+
+A fuller **tail-frame history** recovers the frames TCO erases: each compiled fn
+records itself on entry into a bounded ring-of-rings buffer, so the trace shows
+TCO-elided frames (including the immediate error site) while a tight tail loop
+stays bounded and its non-tail caller context is preserved.
+
+It is **on by default in REPL-driven development** — a `repl` or nREPL session
+turns it on, so an error in code you evaluate or reload shows a tail-frame trace
+with no setup. Because the recording is baked in at compile time, only code
+compiled while a session is live is traced; reload a namespace to trace code that
+was already loaded (e.g. an app's initial `-M:run` load before its nREPL started).
+
+Elsewhere it is off (a small per-call cost, and never emitted into a `jolt build`
+binary). Override with the environment: `JOLT_TRACE=1` forces it on for a whole
+run — including a plain `-M:run`, so the app's own load is traced — and
+`JOLT_TRACE=0` forces it off, even in a REPL/nREPL session.
+
 ## Conformance
 
 The known-working libraries (see [libraries.md](libraries.md)) and the

host/chez/build-joltc.ss

@@ -46,6 +46,15 @@
 (unless (or jb-release? (string=? jb-profile "debug"))
   (error 'build-joltc "profile must be \"release\" or \"debug\"" jb-profile))
 
+;; Version baked into the binary's saved heap. Prefer $JOLT_VERSION (CI sets it to
+;; the release tag); else derive it from git in this checkout; else "dev".
+(define jb-version
+  (let ((env (getenv "JOLT_VERSION")))
+    (if (and env (> (string-length env) 0))
+        env
+        (let ((s (bld-sh-capture "git describe --tags --always --dirty 2>/dev/null")))
+          (if (> (string-length s) 0) s "dev")))))
+
 (define jb-build (string-append jb-out ".build"))
 (bld-check-toolchain)
 (bld-system (string-append "mkdir -p '" (path-parent jb-out) "' '" jb-build "'"))
@@ -136,11 +145,10 @@
 (scheme-start
   (lambda args
     (set-source-roots! (list \"jolt-core\" \"stdlib\"))
-    (guard (v (#t (jolt-report-throwable v (current-error-port))
-                  (let ((bt (jolt-backtrace-string v)))
-                    (when bt (display \"  trace:\\n\" (current-error-port))
-                          (display bt (current-error-port))))
-                  (exit 1)))
+    ;; JOLT_TRACE at RUNTIME (the env is unset at heap-build), before any app ns
+    ;; compiles, so a `-M:run` traces the app's own code.
+    (jolt-trace-init-from-env!)
+    (guard (v (#t (jolt-report-throwable v (current-error-port)) (exit 1)))
       (cond
         ((and (= (length args) 2) (string=? (car args) \"-e\"))
          (let ((result (jolt-final-str
@@ -164,6 +172,10 @@
   (jb-emit-runtime-embeds out)
   (put-string out "\n;; === embedded jolt-core + stdlib source ===\n")
   (jb-emit-source-embeds out)
+  ;; Bake the version into the saved heap (runs at heap-build; loader.ss defined
+  ;; jolt-baked-version above, so this set! resolves).
+  (put-string out (string-append "\n;; === baked version ===\n(set! jolt-baked-version "
+                                 (ei-str-lit jb-version) ")\n"))
   (put-string out "\n;; === joltc launcher ===\n")
   (jb-emit-launcher out)
   (close-port out))
@@ -245,6 +257,8 @@
 ;; table so `build` can foreign-entry them to spill the bundled Chez boots. On
 ;; Linux dlsym can't see executable symbols otherwise (macOS exports them anyway).
 (bld-system (string-append
-  "cc -O2 -rdynamic -I'" bld-csv-dir "' -I'" jb-build "' '" jb-main-c "' '"
+  ;; the embedded jolt_* arrays must be foreign-entry-visible at runtime:
+  ;; -rdynamic on ELF; on Windows an exe needs an export table (GetProcAddress).
+  "cc -O2 " (if bld-nt? "-Wl,--export-all-symbols " "-rdynamic ") "-I'" bld-csv-dir "' -I'" jb-build "' '" jb-main-c "' '"
   bld-csv-dir "/libkernel.a' -o '" jb-out "' " (bld-link-libs)))
 (display (string-append "build-joltc: wrote " jb-out "\n"))

host/chez/build-smoke.sh

@@ -94,6 +94,28 @@ for frame in 'app.util/deep-boom' 'app.util/mid-boom' 'app.core/-main'; do
     exit 1
   fi
 done
+# A built binary runs -main with *ns* = user, like clojure.main — so a runtime
+# resolve of an aliased symbol is nil (the alias lives in the entry ns, not user),
+# matching the JVM and interpreted joltc rather than the entry ns's alias table. A
+# separate app: `resolve` defeats tree-shaking, so keep it out of the shake test's
+# app above.
+nsp="$(dirname "$out")/nsparity"
+mkdir -p "$nsp/src/nsp"
+printf '{:paths ["src"]}\n' > "$nsp/deps.edn"
+printf '(ns nsp.lib)\n(defn thing [] 1)\n' > "$nsp/src/nsp/lib.clj"
+printf '(ns nsp.main (:require [nsp.lib :as l]))\n(defn -main [& _]\n  (println "ns:" (str *ns*))\n  (println "resolve:" (pr-str (resolve (quote l/thing))))\n  (println "ns-resolve:" (pr-str (ns-resolve (quote nsp.lib) (quote thing)))))\n' > "$nsp/src/nsp/main.clj"
+nspout="$(dirname "$out")/nsparity-bin"
+if ! JOLT_PWD="$nsp" bin/joltc build -m nsp.main -o "$nspout" >/dev/null 2>&1; then
+  echo "  FAIL: jolt build of the ns-parity app exited non-zero"; exit 1
+fi
+nsp_out="$(cd / && "$nspout" 2>&1)"
+if ! printf '%s' "$nsp_out" | grep -q 'ns: user' \
+   || ! printf '%s' "$nsp_out" | grep -q '^resolve: nil' \
+   || ! printf '%s' "$nsp_out" | grep -q "ns-resolve: #'nsp.lib/thing"; then
+  echo "  FAIL: built binary -main ns parity — want 'ns: user', 'resolve: nil', ns-resolve found"
+  echo "--- got ----"; echo "$nsp_out"
+  exit 1
+fi
 # Tree-shaking (opt-in): same result, and an unreachable def (the `twice` macro,
 # expanded at AOT and never called at runtime) is dropped.
 if ! JOLT_PWD="$app" bin/joltc build -m app.core -o "$out" --tree-shake >/dev/null 2>&1; then
@@ -129,4 +151,20 @@ if [ "$got_dr" != "42" ]; then
   echo "  FAIL: built #code data reader — want 42, got \`$got_dr\`"; exit 1
 fi
 
-echo "build smoke: passed (release + optimized + direct-link + tree-shake + compiler+core shake + data-reader)"
+# A script namespace with no -main (just top-level side effects) must build and
+# run its top-level forms, then exit cleanly — not crash calling a nil -main.
+nomain="$(dirname "$out")/nomain"
+mkdir -p "$nomain/src"
+printf '{:paths ["src"]}\n' > "$nomain/deps.edn"
+printf '(ns script)\n(println "no-main script ran")\n' > "$nomain/src/script.clj"
+nmout="$(dirname "$out")/nomain-bin"
+if ! JOLT_PWD="$nomain" bin/joltc build -m script -o "$nmout" >/dev/null 2>&1; then
+  echo "  FAIL: jolt build of a no-main script exited non-zero"; exit 1
+fi
+got_nm="$(cd / && "$nmout" 2>&1)"; rc_nm=$?
+if [ "$got_nm" != "no-main script ran" ] || [ "$rc_nm" != "0" ]; then
+  echo "  FAIL: no-main script binary — want 'no-main script ran' rc 0, got \`$got_nm\` rc $rc_nm"
+  exit 1
+fi
+
+echo "build smoke: passed (release + optimized + direct-link + tree-shake + compiler+core shake + data-reader + no-main)"

host/chez/build.ss

@@ -23,7 +23,7 @@
 ;; --- shell helpers ----------------------------------------------------------
 ;; Run a command, return its stdout as one trimmed string ("" on no output).
 (define (bld-sh-capture cmd)
-  (let* ((p (process cmd)) (in (car p)))
+  (let* ((p (process (bld-sh-wrap cmd))) (in (car p)))
     (let loop ((acc '()))
       (let ((l (get-line in)))
         (if (eof-object? l)
@@ -37,7 +37,7 @@
             (loop (cons l acc)))))))
 
 (define (bld-system cmd)
-  (let ((rc (system cmd)))
+  (let ((rc (system (bld-sh-wrap cmd))))
     (unless (zero? rc)
       (error 'jolt-build (string-append "command failed (" (number->string rc) "): " cmd)))))
 
@@ -57,6 +57,24 @@
 ;; --- toolchain discovery ----------------------------------------------------
 (define bld-machine (symbol->string (machine-type)))
 (define bld-osx? (bld-contains? bld-machine "osx"))
+(define bld-nt? (bld-contains? bld-machine "nt"))
+
+;; Chez's system/process run through cmd.exe on Windows; every build command
+;; here is written for sh (MSYS2 provides it). On nt, spill the command to a
+;; script and run `sh <file>` — workspace paths carry no spaces, and the
+;; script file sidesteps cmd's quoting entirely. Identity elsewhere.
+(define bld-shell-counter 0)
+(define (bld-sh-wrap cmd)
+  (if bld-nt?
+      (let* ((tmp (or (getenv "TEMP") (getenv "TMP") "."))
+             (f (begin (set! bld-shell-counter (+ bld-shell-counter 1))
+                       (string-append tmp "\\jolt-sh-"
+                                      (number->string bld-shell-counter) ".sh"))))
+        (let ((p (open-output-file f 'replace)))
+          (put-string p cmd)
+          (close-port p))
+        (string-append "sh " f))
+      cmd))
 
 ;; The Chez executable, for the isolated compile pass (see build-binary step 4).
 (define bld-chez
@@ -94,14 +112,21 @@
 
 ;; Link flags. macOS Homebrew layout for the kernel's lz4/zlib/ncurses deps.
 (define (bld-link-libs)
-  (if bld-osx?
-      (let ((lz4 (bld-sh-capture "brew --prefix lz4 2>/dev/null")))
-        (string-append
-          (if (> (string-length lz4) 0) (string-append "-L" lz4 "/lib ") "")
-          "-llz4 -lz -lncurses -framework Foundation -liconv -lm"))
-      ;; Linux: the Chez kernel pulls in compression (lz4/z), the expression
-      ;; editor (ncurses + terminfo), threads, dlopen, libuuid, and clock_gettime.
-      "-llz4 -lz -lncurses -ltinfo -ldl -lm -lpthread -luuid -lrt"))
+  (cond
+    (bld-osx?
+     (let ((lz4 (bld-sh-capture "brew --prefix lz4 2>/dev/null")))
+       (string-append
+         (if (> (string-length lz4) 0) (string-append "-L" lz4 "/lib ") "")
+         "-llz4 -lz -lncurses -framework Foundation -liconv -lm")))
+    ;; Windows (ta6nt, MinGW-w64 under MSYS2): the Chez kernel pulls in
+    ;; compression, winsock, COM/UUID, and the registry.
+    (bld-nt?
+          ;; -static: a single-file exe (no libwinpthread/libgcc/lz4 DLL deps) —
+     ;; required for a distributable binary and for TLS init consistency.
+     "-static -llz4 -lz -lws2_32 -lrpcrt4 -lole32 -luuid -ladvapi32 -luser32 -lshell32 -lm")
+    ;; Linux: the Chez kernel pulls in compression (lz4/z), the expression
+    ;; editor (ncurses + terminfo), threads, dlopen, libuuid, and clock_gettime.
+    (else "-llz4 -lz -lncurses -ltinfo -ldl -lm -lpthread -luuid -lrt")))
 
 ;; --- runtime manifest (mirrors host/chez/cli.ss's load order) ---------------
 ;; A line is either literal Scheme text to inline, or a tag whose emission the build
@@ -411,7 +436,15 @@
 ;; direct-link?: opt-in closed-world direct-linking (app->app calls bind directly,
 ;; no runtime redefinition). Off by default in every mode — release stays
 ;; dynamically linked.
+(define (bld-suffix? s suf)
+  (let ((n (string-length s)) (m (string-length suf)))
+    (and (>= n m) (string=? (substring s (- n m) n) suf))))
 (define (build-binary entry-ns out-path mode natives embed-dirs ext-roots direct-link? tree-shake?)
+  ;; Windows executables carry .exe; normalize here so the append-payload and
+  ;; cc paths agree and the shell can run the result.
+  (let ((out-path (if (and bld-nt? (not (bld-suffix? out-path ".exe")))
+                      (string-append out-path ".exe")
+                      out-path)))
   ;; The self-contained path (jolt-embedded-bytes "stub/launcher") needs no csv
   ;; kernel files, no Chez, no cc — only the legacy cc path does.
   (unless (jolt-embedded-bytes "stub/launcher") (bld-check-toolchain))
@@ -538,11 +571,23 @@
                             "))\n"
                             "                (list \"jolt-core\" \"stdlib\"))))\n"))
           (put-string out (string-append
-                            "    (let ((mainv (var-deref " (ei-str-lit entry-ns) " \"-main\")))\n"
+                            ;; Call -main only if the entry namespace defines one;
+                            ;; a script ns (top-level side effects, no -main) has
+                            ;; already run its forms at heap build, so invoking a nil
+                            ;; -main would crash ("nil cannot be cast to IFn") — just
+                            ;; exit cleanly instead.
+                            "    (let ((maincell (var-cell-lookup " (ei-str-lit entry-ns) " \"-main\")))\n"
                             ;; render an uncaught throw (+ Clojure backtrace) instead
                             ;; of Chez's opaque dump, then exit non-zero.
                             "      (guard (v (#t (jolt-report-throwable v (current-error-port)) (exit 1)))\n"
-                            "        (apply jolt-invoke mainv args)))\n"
+                            ;; Loading the app left the current ns at the entry ns; reset
+                            ;; it to `user` before -main, matching clojure.main (*ns* is
+                            ;; `user` when a `-m` -main runs, so a runtime resolve of an
+                            ;; aliased symbol behaves the same as on the JVM / interpreted
+                            ;; joltc, not off the entry ns's alias table).
+                            "        (set-chez-ns! \"user\")\n"
+                            "        (when (and maincell (var-cell-defined? maincell))\n"
+                            "          (apply jolt-invoke (var-cell-root maincell) args))))\n"
                             "    (exit 0)))\n"))
           (close-port out))
         ;; 4. compile -> boot -> link. Two paths, chosen by whether this process
@@ -558,7 +603,7 @@
             (build-self-contained entry-ns out-path mode builddir flat-ss flat-so boot
                                   (bld-native-link-flags natives))
             (build-with-cc entry-ns out-path mode builddir flat-ss flat-so boot boot-h main-c
-                           (bld-native-link-flags natives))))))))
+                           (bld-native-link-flags natives)))))))))
 
 ;; --- self-contained link (in-process compile + append the boot to the stub) ---
 ;; compile-file runs against the DEFAULT interaction environment, so the boot's

host/chez/cli.ss

@@ -11,6 +11,26 @@
 
 (define cli-args (cdr (command-line)))   ; drop the script name
 
+;; Fail early and actionably when the vendored submodules aren't checked out —
+;; a plain `git clone` or GitHub's auto-generated "Source code" release archive
+;; lacks them, and the raw failure ("load failed for vendor/irregex/irregex.scm")
+;; doesn't say how to fix it. (The self-contained joltc binary embeds these and
+;; never runs this file.)
+(unless (file-exists? "vendor/irregex/irregex.scm")
+  (display "jolt: vendor submodules are missing (vendor/irregex).
+" (current-error-port))
+  (display "GitHub's 'Source code' release archives don't include submodules.
+" (current-error-port))
+  (display "Clone the repo instead:
+" (current-error-port))
+  (display "  git clone --recurse-submodules https://github.com/jolt-lang/jolt.git
+" (current-error-port))
+  (display "or, in an existing checkout:
+" (current-error-port))
+  (display "  git submodule update --init --recursive
+" (current-error-port))
+  (exit 1))
+
 (load "host/chez/rt.ss")
 (set-chez-ns! "clojure.core")
 (load "host/chez/seed/prelude.ss")
@@ -46,6 +66,9 @@
       (when bt (display "  trace:\n" port) (display bt port)))
     (exit 1)))
 
+;; JOLT_TRACE opt-in, at runtime (before any app ns compiles) so the app is traced.
+(jolt-trace-init-from-env!)
+
 (guard (v (#t (jolt-report-uncaught v)))
   (cond
     ;; -e EXPR — evaluate one expression and print it (blank for nil). Wrapped in

host/chez/collections.ss

@@ -298,8 +298,21 @@
 (define empty-pmap-hash (make-pmap empty-hnode 0 #f))      ; hash-order backing (sets)
 (define pmap-absent (list 'absent))    ; unique missing-key sentinel
 ;; PersistentArrayMap threshold: assoc of a new key promotes to hash mode once the
-;; map already holds 8 entries (array.length >= 16 in the reference).
+;; map already holds 8 entries (array.length >= 16 in the reference). Clojure 1.13
+;; raised the limit to 64 for maps whose keys are ALL keywords (the common
+;; keyword-map case); mixed-key maps still cap at 8.
 (define array-map-limit 8)
+(define array-map-limit-kw 64)
+(define (all-keywords? ks)
+  (or (null? ks) (and (keyword? (car ks)) (all-keywords? (cdr ks)))))
+;; Should a map of `cnt` entries with insertion order `ord` stay in array mode
+;; when key `k` is added? Under 8 always; a keyword-only map (existing keys + the
+;; new key all keywords) grows to 64; otherwise it caps at 8.
+(define (pmap-array-keep? cnt ord k)
+  (cond ((fx<? cnt array-map-limit) #t)
+        ((fx>=? cnt array-map-limit-kw) #f)
+        ((and (keyword? k) (all-keywords? ord)) #t)
+        (else #f)))
 (define (append-key ord k) (append ord (list k)))
 (define (remove-key ord k) (let loop ((o ord)) (cond ((null? o) '()) ((jolt= (car o) k) (cdr o)) (else (cons (car o) (loop (cdr o)))))))
 
@@ -310,7 +323,7 @@
   (let* ((added (box #f)) (r (node-assoc (pmap-root m) 0 (key-hash k) k v added))
          (cnt (pmap-cnt m)) (ord (pmap-order m)))
     (if (unbox added)
-        (if (and ord (fx<? cnt array-map-limit))
+        (if (and ord (pmap-array-keep? cnt ord k))
             (make-pmap r (fx+ cnt 1) (append-key ord k))
             (make-pmap r (fx+ cnt 1) #f))
         (make-pmap r cnt ord))))
@@ -352,10 +365,14 @@
         (let loop ((ks ord) (a acc))
           (if (null? ks) a (loop (cdr ks) (proc (car ks) (pmap-get m (car ks) jolt-nil) a))))
         (node-fold (pmap-root m) proc acc))))
-;; map LITERAL ({...}): array map up to 8 entries, hash map beyond (RT.map).
+;; map LITERAL ({...}): array map up to 8 entries (64 if keyword-only, per 1.13),
+;; hash map beyond (RT.map).
 (define (jolt-hash-map . kvs)
   (let loop ((m empty-pmap) (kvs kvs))
-    (cond ((null? kvs) (if (fx>? (pmap-cnt m) array-map-limit) (pmap->hash m) m))
+    (cond ((null? kvs)
+           (let ((cnt (pmap-cnt m)) (ord (pmap-order m)))
+             (if (fx>? cnt (if (all-keywords? ord) array-map-limit-kw array-map-limit))
+                 (pmap->hash m) m)))
           ((null? (cdr kvs)) (error 'hash-map "odd number of map literal entries"))
           (else (loop (pmap-put-ordered m (car kvs) (cadr kvs)) (cddr kvs))))))
 ;; array-map ctor: insertion-ordered regardless of size (createAsIfByAssoc).

host/chez/compile-eval.ss

@@ -110,6 +110,38 @@
 ;; older seed during the first re-mint pass.
 (let ((scv (var-deref "jolt.backend-scheme" "set-var-cache!")))
   (when (procedure? scv) (scv #t)))
+;; JOLT_TRACE is a falsey value (case-insensitive) — the single predicate both the
+;; dev-mode enable and the whole-run enable consult, so "off" never accidentally
+;; means "on". An empty / unset value is NOT falsey here — it carries no signal, so
+;; dev mode still traces and a whole run still doesn't.
+(define (jolt-trace-env-off? e)
+  (and (string? e)
+       (let ((s (string-downcase e)))
+         (or (string=? s "0") (string=? s "false") (string=? s "no")
+             (string=? s "off") (string=? s "n")))))
+;; Tail-frame history. Turning it on makes the emitter add a per-fn history push to
+;; every fn compiled AFTERWARD, and allocates this thread's ring. Suppressed when
+;; JOLT_TRACE is a falsey value, so JOLT_TRACE=0 / off / no disables it in dev mode.
+(define (jolt-enable-trace!)
+  (unless (jolt-trace-env-off? (getenv "JOLT_TRACE"))
+    (let ((stf (var-deref "jolt.backend-scheme" "set-trace-frames!")))
+      (when (procedure? stf) (stf #t)))
+    (jolt-trace-enable!)))
+;; Exposed so the REPL / nREPL entrypoints (jolt.main, jolt.nrepl) can turn tracing
+;; on for REPL-driven development without the user setting JOLT_TRACE. Because the
+;; push is baked in at compile time, only code compiled after this call is traced —
+;; which is exactly the code you eval / reload in a live session.
+(def-var! "jolt.host" "enable-trace!" jolt-enable-trace!)
+;; Explicit opt-in for a whole run (JOLT_TRACE=1): turn tracing on BEFORE any app
+;; namespace is compiled, so a plain `-M:run` traces the app's own code too. Called
+;; from the runtime entrypoints (cli.ss, and the built joltc launcher) — NOT at load
+;; time: a built joltc runs top-level forms at heap-build time, where JOLT_TRACE is
+;; always unset, so a load-time check would never see the user's runtime env. Only an
+;; affirmative value (set, non-empty, not falsey) forces it on.
+(define (jolt-trace-init-from-env!)
+  (let ((e (getenv "JOLT_TRACE")))
+    (when (and e (fx>? (string-length e) 0) (not (jolt-trace-env-off? e)))
+      (jolt-enable-trace!))))
 
 ;; (with-meta sym m) -> sym, else x — an (ns ^:no-doc name …) yields the name with
 ;; reader metadata as a with-meta form; strip it to read the bare ns symbol.
@@ -235,6 +267,9 @@
      ;; record this form's source location first, so a compile- or run-time error
      ;; in it reports the right place.
      (jolt-enter-form! form)
+     ;; drop tail-frame history from earlier top-level forms, so an error's trace
+     ;; shows only this form's own call history (a no-op unless JOLT_TRACE is on).
+     (jolt-trace-reset!)
      (eval (read (open-input-string (jolt-analyze-emit-form form ns)))
            (interaction-environment)))))
 

host/chez/emit-image.ss

@@ -46,6 +46,10 @@
 ;; after it). Guarded for the first re-mint pass off an older seed.
 (let ((scv (var-deref "jolt.backend-scheme" "set-var-cache!")))
   (when (procedure? scv) (scv #f)))
+;; Tail-frame tracing off for the mint + `jolt build`: the seed must stay a
+;; byte-fixpoint, and a built app should carry no per-call trace overhead.
+(let ((stf (var-deref "jolt.backend-scheme" "set-trace-frames!")))
+  (when (procedure? stf) (stf #f)))
 (define (ei-compile-form ctx f optimize?)
   (let ((ir (jolt-ce-analyze ctx f)))
     (jolt-ce-emit-top (if optimize? (jolt-ce-run-passes ir ctx) ir))))

host/chez/java/concurrency.ss

@@ -579,9 +579,9 @@
 ;; pthread_sigmask"). Guard so a non-POSIX host yields #f; jolt-set-sigint-blocked
 ;; then no-ops (Windows delivers ^C through the console, not a per-thread mask).
 (define c-pthread-sigmask
-  (guard (e (#t #f)) (foreign-procedure "pthread_sigmask" (int u8* u8*) int)))
-(define c-sigemptyset (guard (e (#t #f)) (foreign-procedure "sigemptyset" (u8*) int)))
-(define c-sigaddset (guard (e (#t #f)) (foreign-procedure "sigaddset" (u8* int) int)))
+  (jolt-foreign-proc-safe "pthread_sigmask" '(int u8* u8*) 'int))
+(define c-sigemptyset (jolt-foreign-proc-safe "sigemptyset" '(u8*) 'int))
+(define c-sigaddset (jolt-foreign-proc-safe "sigaddset" '(u8* int) 'int))
 ;; POSIX SIG_BLOCK/SIG_UNBLOCK numerics differ by platform: Linux/glibc 0/1,
 ;; Darwin/macOS 1/2 (SIG_UNBLOCK is SIG_BLOCK+1 on both). Resolve SIG_BLOCK for
 ;; this host from the machine-type symbol — macOS builds contain "osx".

host/chez/java/host-static-methods.ss

@@ -55,9 +55,7 @@
     (lambda ()
       (unless tried?
         (set! tried? #t)
-        (set! fp (guard (e (#t #f))
-                   (load-shared-object #f)
-                   (foreign-procedure "sched_yield" () int))))
+        (set! fp (jolt-foreign-proc-safe "sched_yield" '() 'int)))
       (if fp (fp) (sleep (make-time 'time-duration 0 0)))
       jolt-nil)))
 

host/chez/java/io.ss

@@ -80,13 +80,18 @@
 ;; every Chez binary) — no external toolchain. Falls back to /bin/sh chmod if the
 ;; symbol can't be resolved.
 (define jolt-chmod-755
-  (let ((c (guard (e (#t #f))
-             (load-shared-object #f)
-             (foreign-procedure "chmod" (string int) int))))
+  (let ((c (jolt-foreign-proc-safe "chmod" '(string int) 'int)))
     (lambda (path)
-      (if c
-          (c path #o755)
-          (system (string-append "chmod 755 '" path "'"))))))
+      (cond
+        (c (c path #o755))
+        ;; Windows has no chmod and needs none (execute is by extension)
+        ((let ((m (symbol->string (machine-type))))
+           (let loop ((i 0))
+             (cond ((> (+ i 2) (string-length m)) #f)
+                   ((string=? (substring m i (+ i 2)) "nt") #t)
+                   (else (loop (+ i 1))))))
+         0)
+        (else (system (string-append "chmod 755 '" path "'")))))))
 
 ;; A user-facing relative path resolves against JOLT_PWD — the user's cwd before
 ;; the launcher cd'd to the jolt repo root — matching the JVM, where io/file is

host/chez/joltc-selfbuild-smoke.sh

@@ -42,6 +42,20 @@ if [ "$got_e" != "45" ]; then
   exit 1
 fi
 
+# 2b. JOLT_TRACE must take effect in the BUILT binary. The env check runs at
+# runtime (the launcher), NOT at heap-build where JOLT_TRACE is always unset — so
+# an uncaught error shows a tail-frame trace recovering the TCO-elided chain, and
+# exactly ONE trace block (the launcher must not double-print it).
+got_tr="$(env -i HOME="$HOME" JOLT_TRACE=1 "$joltc" -e '(defn a [x] (+ x 1)) (defn b [x] (a x)) (b :x)' 2>&1)"
+if ! printf '%s' "$got_tr" | grep -q '  trace:' || ! printf '%s' "$got_tr" | grep -q 'b'; then
+  echo "  FAIL: JOLT_TRACE=1 in the built joltc produced no tail-frame trace"
+  echo "--- got ---"; echo "$got_tr"; exit 1
+fi
+if [ "$(printf '%s' "$got_tr" | grep -c '  trace:')" != "1" ]; then
+  echo "  FAIL: built joltc double-printed the trace block"
+  echo "--- got ---"; echo "$got_tr"; exit 1
+fi
+
 # 3. Build an app through the distributed joltc with an EMPTY environment — no
 # PATH at all, so no chez, no cc, no shell tools are reachable. This is the core
 # guarantee: joltc compiles apps entirely on its own.

host/chez/loader.ss

@@ -384,3 +384,14 @@
 (def-var! "jolt.host" "load-namespace" (lambda (n) (load-namespace n) jolt-nil))
 (def-var! "jolt.host" "file-exists?" (lambda (p) (if (file-exists? p) #t #f)))
 (def-var! "jolt.host" "getenv" (lambda (n) (let ((v (getenv n))) (if v v jolt-nil))))
+
+;; jolt version string. A self-contained binary build bakes the real tag into the
+;; saved heap by emitting (set! jolt-baked-version "…") in flat.ss; a dev run off
+;; the seed leaves it #f and falls back to $JOLT_VERSION (bin/joltc sets it from
+;; `git describe`), then "dev".
+(define jolt-baked-version #f)
+(def-var! "jolt.host" "jolt-version"
+  (lambda ()
+    (or jolt-baked-version
+        (let ((v (getenv "JOLT_VERSION"))) (and v (> (string-length v) 0) v))
+        "dev")))

host/chez/rt.ss

@@ -11,6 +11,17 @@
 ;; Emitted programs do `(load "host/chez/rt.ss")`; this loads values.ss in turn.
 
 (load "host/chez/values.ss")
+;; Resolve a libc entry point at RUN time. A literal (foreign-procedure "name" …)
+;; in COMPILED code becomes a fasl relocation resolved when the boot loads — on a
+;; platform lacking the symbol (chmod/sigaddset on Windows) that kills the boot
+;; before any guard can run. eval defers the lookup to evaluation time, where the
+;; guard works; returns #f when the entry doesn't exist.
+(define (jolt-foreign-proc-safe name args res)
+  (guard (e (#t #f))
+    (load-shared-object #f)
+    (and (foreign-entry? name)
+         (eval `(foreign-procedure ,name ,args ,res)))))
+
 (load "host/chez/collections.ss")
 (load "host/chez/seq.ss")
 
@@ -49,6 +60,112 @@
 ;; stack trace (source-registry.ss). call/cc is paid only on a throw, never per
 ;; call; the captured k is walked, never invoked.
 (define jolt-throw-cont (make-thread-parameter #f))
+
+;; --- tail-frame history: a ring of rings (opt-in) ----------------------------
+;; TCO erases tail-called frames from the native continuation, so an uncaught
+;; error's backtrace shows only the surviving non-tail spine — the immediate error
+;; site is often a tail call and is missing. When tracing is enabled (JOLT_TRACE,
+;; wired in compile-eval.ss), each compiled fn records its frame-name on entry, and
+;; the reporter reads this history to recover TCO-elided frames.
+;;
+;; The store is MIT-Scheme's "history" shape — a ring of rings. The OUTER ring
+;; holds one RIB per non-tail subproblem (the real call spine); each rib's INNER
+;; ring holds the recent tail-calls made AT that subproblem. A non-tail entry
+;; advances the outer ring (a fresh rib); a tail entry rotates the current rib's
+;; inner ring. So a tight tail loop (mutual recursion, a non-recur self-tail-call)
+;; churns ONE rib's small inner ring instead of flushing the outer spine — the
+;; caller context that led into the loop survives. Both rings are fixed-size, so
+;; the whole history is bounded: a constant space factor, NOT a change to the
+;; asymptotic space TCO guarantees.
+;;
+;; Whether an entry is tail or non-tail is set by the CALLER: the emitter marks a
+;; tail call with (jolt-trace-mark! #t) right before it; a non-tail entry is the
+;; default. NOTE this is best-effort: a tail call routed through jolt-invoke to a
+;; target that has no entry prologue (a core/native fn, an anonymous fn held in a
+;; var) does not consume the mark, so a following non-tail frame can be mislabeled
+;; as a tail rotation — a cosmetic mis-grouping in the trace, never a wrong result.
+(define jolt-trace-outer-size 48)          ; ribs (non-tail spine depth kept)
+(define jolt-trace-inner-size 6)           ; tail-calls kept per subproblem
+;; A history: #(ribs-vector outer-head outer-count). A rib: #(name-vector head count).
+(define (jolt-make-rib) (vector (make-vector jolt-trace-inner-size #f) 0 0))
+(define (jolt-make-history)
+  (let ((ribs (make-vector jolt-trace-outer-size #f)))
+    (let loop ((i 0))
+      (when (fx<? i jolt-trace-outer-size)
+        (vector-set! ribs i (jolt-make-rib)) (loop (fx+ i 1))))
+    (vector ribs 0 0)))
+;; A global switch (all threads) plus a per-thread ring, lazily created on first
+;; use — so code run on a spawned thread (a future/agent) records into ITS OWN
+;; history, not the enabling thread's (make-thread-parameter hands a new thread the
+;; initial #f, so we can't rely on inheritance).
+(define jolt-trace-on? #f)
+(define jolt-trace-ring (make-thread-parameter #f))
+(define jolt-trace-tail? (make-thread-parameter #f))   ; caller-set, consumed per entry
+(define (jolt-trace-enable!) (set! jolt-trace-on? #t) (jolt-trace-ring (jolt-make-history)))
+;; this thread's ring, created on demand while tracing is on
+(define (jolt-trace-cur-ring)
+  (or (jolt-trace-ring)
+      (and jolt-trace-on? (let ((h (jolt-make-history))) (jolt-trace-ring h) h))))
+;; Drop accumulated history at a top-level boundary (compile-eval.ss calls this per
+;; top-level form) so an error's trace shows only the forms that led to it, not the
+;; frames of earlier, already-returned REPL/eval forms.
+(define (jolt-trace-reset!)
+  (when (jolt-trace-ring) (jolt-trace-ring (jolt-make-history)) (jolt-trace-tail? #f)))
+(define (jolt-trace-mark! t) (jolt-trace-tail? t))
+
+;; push name into a rib's inner ring
+(define (jolt-rib-push! rib name)
+  (let ((buf (vector-ref rib 0)) (i (vector-ref rib 1)) (cnt (vector-ref rib 2)))
+    (vector-set! buf i name)
+    (vector-set! rib 1 (fxmod (fx+ i 1) jolt-trace-inner-size))
+    (when (fx<? cnt jolt-trace-inner-size) (vector-set! rib 2 (fx+ cnt 1)))))
+;; a non-tail entry: advance the outer ring, reset the new rib, seed it with name
+(define (jolt-history-nontail! h name)
+  (let* ((ribs (vector-ref h 0)) (oh (vector-ref h 1)) (oc (vector-ref h 2))
+         (rib (vector-ref ribs oh)))
+    (vector-set! rib 1 0) (vector-set! rib 2 0)
+    (jolt-rib-push! rib name)
+    (vector-set! h 1 (fxmod (fx+ oh 1) jolt-trace-outer-size))
+    (when (fx<? oc jolt-trace-outer-size) (vector-set! h 2 (fx+ oc 1)))))
+;; a tail entry: rotate the CURRENT rib's inner ring (bootstrap a rib if none yet)
+(define (jolt-history-tail! h name)
+  (if (fx=? (vector-ref h 2) 0)
+      (jolt-history-nontail! h name)
+      (let* ((ribs (vector-ref h 0))
+             (cur (fxmod (fx+ (fx- (vector-ref h 1) 1) jolt-trace-outer-size)
+                         jolt-trace-outer-size)))
+        (jolt-rib-push! (vector-ref ribs cur) name))))
+;; Record a frame entry, routed by the caller's tail mark; then reset the mark so a
+;; subsequent entry reached WITHOUT a mark (e.g. via apply) defaults to non-tail.
+(define (jolt-trace-push! name)
+  (let ((h (jolt-trace-cur-ring)))
+    (when h
+      (if (jolt-trace-tail?) (jolt-history-tail! h name) (jolt-history-nontail! h name))
+      (jolt-trace-tail? #f)))
+  jolt-nil)
+
+;; a rib's inner names, most-recent (deepest) tail first
+(define (jolt-rib-names rib)
+  (let ((buf (vector-ref rib 0)) (head (vector-ref rib 1)) (cnt (vector-ref rib 2)))
+    (let loop ((k 1) (acc '()))
+      (if (fx>? k cnt)
+          (reverse acc)
+          (loop (fx+ k 1)
+                (cons (vector-ref buf (fxmod (fx+ (fx- head k) jolt-trace-inner-size)
+                                             jolt-trace-inner-size))
+                      acc))))))
+;; The whole history flattened to frame-names, most-recent (deepest) first:
+;; current rib's tail-history, then its non-tail caller's, and so on outward.
+(define (jolt-trace-snapshot)
+  (let ((h (jolt-trace-ring)))
+    (if (not h) '()
+        (let* ((ribs (vector-ref h 0)) (oh (vector-ref h 1)) (oc (vector-ref h 2)))
+          (let loop ((k 1) (acc '()))
+            (if (fx>? k oc)
+                (apply append (reverse acc))
+                (let ((idx (fxmod (fx+ (fx- oh k) jolt-trace-outer-size) jolt-trace-outer-size)))
+                  (loop (fx+ k 1) (cons (jolt-rib-names (vector-ref ribs idx)) acc)))))))))
+
 (define-condition-type &jolt-throw &condition
   make-jolt-throw-condition jolt-throw-condition?
   (value jolt-throw-condition-value))

host/chez/run-corpus.ss

@@ -11,7 +11,7 @@
 ;; reset between cases so there is no leakage — same isolation a fresh process gives.
 ;;
 ;;   chez --script host/chez/run-corpus.ss
-;;   JOLT_CHEZ_ZJ_FLOOR=N   override the regression floor (default 2730)
+;;   JOLT_CHEZ_ZJ_FLOOR=N   override the regression floor (default 3390)
 ;;   JOLT_CORPUS_LIMIT=N    every-Nth stride (fast iteration; floor drops to 0)
 ;;   JOLT_DUMP_CRASH_LABELS=1   list crash + allowlisted labels
 (import (chezscheme))
@@ -196,7 +196,7 @@
 
 ;; Regression floor: fail on any NEW divergence or if pass drops below the floor.
 (define base-floor (let ((s (getenv "JOLT_CHEZ_ZJ_FLOOR")))
-                     (if s (string->number s) 2730)))
+                     (if s (string->number s) 3390)))
 (define floor (if limit 0 base-floor))
 (when (or (> (length diverged) 0) (< pass floor))
   (printf "REGRESSION: pass ~a < floor ~a or ~a new divergence(s)\n"

host/chez/smoke.sh

@@ -30,6 +30,39 @@ check_loc() {
   fi
 }
 
+# An uncaught error's stack trace must name the runtime-eval'd fn frames that
+# survive TCO (the non-tail spine), even though the eval path registers no source
+# map — "print what is available". Asserts a substring appears under "  trace:".
+check_trace() {
+  err="$(bin/joltc -e "$1" 2>&1 >/dev/null)"
+  if printf '%s' "$err" | grep -q '  trace:' && printf '%s' "$err" | grep -q "$2"; then
+    pass=$((pass + 1))
+  else
+    echo "  FAIL (trace): $1"
+    echo "    want stderr trace to contain \`$2\`, got \`$err\`"
+    fails=$((fails + 1))
+  fi
+}
+
+# JOLT_TRACE opts into the tail-frame history (the ring of rings): every $2 (an
+# ERE) must match the "  trace:" block. Used to assert TCO-elided frames are
+# recovered and non-tail caller context survives a tail loop.
+check_trace_on() {
+  err="$(JOLT_TRACE=1 bin/joltc -e "$1" 2>&1 >/dev/null)"
+  ok=1
+  printf '%s' "$err" | grep -q '  trace:' || ok=0
+  shift
+  for want in "$@"; do
+    printf '%s' "$err" | grep -Eq "$want" || ok=0
+  done
+  if [ "$ok" = 1 ]; then
+    pass=$((pass + 1))
+  else
+    echo "  FAIL (trace-on): want [$*] in trace, got \`$err\`"
+    fails=$((fails + 1))
+  fi
+}
+
 check '(+ 1 2)' '3'
 check '(defn fib [n] (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2))))) (fib 15)' '610'
 check '(->> (range 10) (filter even?) (map (fn [x] (* x x))) (reduce +))' '120'
@@ -60,6 +93,53 @@ check '(try (load-string "(+") (catch :default e (ex-message e)))' 'EOF while re
 check_loc '(throw (ex-info "boom" {}))' 'boom'
 check_loc '(do (+ 1 1) (/ 1 0))' '  at 1:'
 
+# Runtime-eval'd fns aren't source-mapped, but their native frame names survive on
+# the non-tail spine; the trace must show them. deepest/+ are tail calls (erased);
+# middle and outer wait on a non-tail (inc …) so their frames are live at the throw.
+trace_prog='(defn deepest [x] (+ x 1)) (defn middle [x] (inc (deepest x))) (defn outer [x] (inc (middle x))) (outer :nan)'
+check_trace "$trace_prog" 'middle'
+check_trace "$trace_prog" 'outer'
+
+# JOLT_TRACE (tail-frame history / ring of rings). An all-tail chain is entirely
+# TCO-erased from the continuation, but the history recovers every frame — incl.
+# `deepest`, the actual error site.
+check_trace_on '(defn deepest [x] (+ x 1)) (defn middle [x] (deepest x)) (defn outer [x] (middle x)) (outer :nan)' \
+  'deepest' 'middle' 'outer'
+# A tail loop (a<->b) under a NON-tail caller: the loop is confined to one rib's
+# bounded inner ring, so the caller context (`driver`, `top`) is NOT flushed out —
+# the point of the ring of rings.
+check_trace_on '(declare b) (defn a [n] (if (zero? n) (+ :x 1) (b (dec n)))) (defn b [n] (a n)) (defn driver [] (inc (a 6))) (defn top [] (inc (driver))) (top)' \
+  'driver' 'top'
+# A ^long/^double return hint wraps the body in a coercion, so the hinted fn's call
+# is NOT a tail call — its own frame is still live and must appear (not be elided).
+check_trace_on '(defn g [n] (+ :x n)) (defn ^long f [n] (g n)) (f 3)' 'f' 'g'
+# History is per top-level form: a later form's error trace shows its own frames
+# (h2/u2), not frames from an earlier, already-returned form (h1/u1).
+check_trace_on '(defn h1 [x] (inc x)) (defn u1 [] (inc (h1 5))) (u1) (defn h2 [x] (+ :x x)) (defn u2 [] (inc (h2 5))) (u2)' \
+  'h2' 'u2'
+err_stale="$(JOLT_TRACE=1 bin/joltc -e '(defn h1 [x] (inc x)) (defn u1 [] (inc (h1 5))) (u1) (defn h2 [x] (+ :x x)) (defn u2 [] (inc (h2 5))) (u2)' 2>&1 >/dev/null)"
+if printf '%s' "$err_stale" | grep -q 'h1'; then
+  echo "  FAIL (trace-on): stale frame h1 from an earlier form leaked into the trace"
+  fails=$((fails + 1))
+else
+  pass=$((pass + 1))
+fi
+# A file-backed project run maps each runtime-compiled frame to ns/name (file:line)
+# — the eval path registers source in trace mode, so the trace isn't bare names.
+tr_proj="$(mktemp -d)"
+mkdir -p "$tr_proj/src/tp"
+printf '{:paths ["src"] :aliases {:run {:main-opts ["-m" "tp.core"]}}}\n' > "$tr_proj/deps.edn"
+printf '(ns tp.core)\n(defn deep [x] (+ x 1))\n(defn mid [x] (inc (deep x)))\n(defn -main [& _] (mid :nan))\n' > "$tr_proj/src/tp/core.clj"
+tr_out="$(JOLT_TRACE=1 JOLT_PWD="$tr_proj" bin/joltc -M:run 2>&1)"
+if printf '%s' "$tr_out" | grep -Eq 'tp\.core/deep \(.*/tp/core\.clj:2\)'; then
+  pass=$((pass + 1))
+else
+  echo "  FAIL: JOLT_TRACE trace should map a frame to ns/name (file:line)"
+  printf '%s\n' "$tr_out" | sed 's/^/    | /'
+  fails=$((fails + 1))
+fi
+rm -rf "$tr_proj"
+
 # --help prints usage, and lists the nREPL server under its real flag name.
 help_out="$(bin/joltc --help 2>/dev/null)"
 if printf '%s' "$help_out" | grep -q -- '--nrepl-server'; then
@@ -159,5 +239,25 @@ else
   fails=$((fails + 1))
 fi
 
+# REPL-driven development traces by default: an error in an evaluated form shows a
+# tail-frame backtrace with no JOLT_TRACE set. rb tail-calls ra tail-calls +, all
+# TCO-elided from the continuation — only the history recovers them.
+repl_err="$(printf '(defn ra [x] (+ x 1))\n(defn rb [x] (ra x))\n(rb :nan)\n:exit\n' | bin/joltc repl 2>&1)"
+if printf '%s' "$repl_err" | grep -q '  trace:' && printf '%s' "$repl_err" | grep -q 'rb'; then
+  pass=$((pass + 1))
+else
+  echo "  FAIL: a REPL error should show a tail-frame trace by default"
+  printf '%s\n' "$repl_err" | sed 's/^/    | /'
+  fails=$((fails + 1))
+fi
+# JOLT_TRACE=0 opts out — no trace in the REPL.
+repl_off="$(printf '(defn ra [x] (+ x 1))\n(defn rb [x] (ra x))\n(rb :nan)\n:exit\n' | JOLT_TRACE=0 bin/joltc repl 2>&1)"
+if printf '%s' "$repl_off" | grep -q '  trace:'; then
+  echo "  FAIL: JOLT_TRACE=0 should suppress the REPL trace"
+  fails=$((fails + 1))
+else
+  pass=$((pass + 1))
+fi
+
 echo "cli smoke: $pass passed, $fails failed"
 [ "$fails" -eq 0 ]

host/chez/source-registry.ss

@@ -57,10 +57,36 @@
                       ((symbol? nm) (symbol->string nm))
                       (else #f)))))))
 
-;; Walk a continuation, returning the registered jolt frames (innermost first) as
-;; (frame-name . record) pairs, where record is #(ns name file line) or the symbol
-;; 'ambiguous. Unmapped frames (host spine, anonymous lambdas) are skipped; raw
-;; depth is capped.
+;; Frame names that are pure Chez / jolt-runtime plumbing — the eval boundary,
+;; the var-cell trampoline, continuation/winder internals. They carry no Clojure
+;; meaning, so an unmapped frame with one of these names is dropped from the trace
+;; (a MAPPED frame is always kept — a jolt fn that happens to share the name still
+;; resolves to its source). Any name Chez prefixes with `$` (system) or that jolt
+;; prefixes with `jolt-` (host runtime) is plumbing too.
+(define srcreg-plumbing-names
+  (let ((h (make-hashtable string-hash string=?)))
+    (for-each (lambda (s) (hashtable-set! h s #t))
+              '("dynamic-wind" "winder-dummy" "ksrc" "invoke" "apply"
+                "call-with-values" "call/cc" "call-with-current-continuation"
+                "raise" "raise-continuable" "with-exception-handler" "guard"
+                "eval" "compile" "interpret" "expand" "read" "load"
+                ;; host dispatch/coercion helpers (not `jolt-` prefixed) that carry
+                ;; no Clojure meaning in a trace
+                "record-method-dispatch" "protocol-resolve" "devirt-resolve"
+                "list->cseq" "host-static-call" "host-call"))
+    h))
+(define (srcreg-plumbing-name? nm)
+  (or (hashtable-ref srcreg-plumbing-names nm #f)
+      (and (fx>? (string-length nm) 0) (char=? (string-ref nm 0) #\$))
+      (and (fx>=? (string-length nm) 5) (string=? (substring nm 0 5) "jolt-"))))
+
+;; Walk a continuation, returning its frames (innermost first) as (frame-name .
+;; record) pairs. record is a source vector #(ns name file line) for a frame that
+;; maps to registered Clojure source, the symbol 'ambiguous for a short name shared
+;; across namespaces, or #f for an unmapped-but-named frame (the common case on the
+;; open-world eval path, where nothing is registered — the bare frame name is still
+;; a useful trace line). Plumbing frames (host spine, eval boundary) and unnamed
+;; frames are skipped; raw depth is capped.
 (define (jolt-frame-records k)
   ;; read the env at call time, not load time: a built binary runs top-level forms
   ;; at heap-build time, where this would always be unset.
@@ -70,39 +96,84 @@
       (if (or (not io) (fx>=? n 400))
           (reverse acc)
           (let* ((nm (srcreg-frame-name io))
-                 (src (and nm (hashtable-ref source-registry nm #f))))
+                 (src (and nm (hashtable-ref source-registry nm #f)))
+                 ;; keep a frame that maps, or any named frame that isn't plumbing
+                 (keep? (and nm (or src (not (srcreg-plumbing-name? nm))))))
             (when (and debug? nm)
-              (display (string-append "  [frame] " nm (if src " *MAPPED*" "") "\n")
+              (display (string-append "  [frame] " nm (if src " *MAPPED*"
+                                                          (if keep? "" " (skipped)")) "\n")
                        (current-error-port)))
             (loop (guard (e (#t #f)) (io 'link)) (fx+ n 1)
-                  (if src (cons (cons nm src) acc) acc))))))))
+                  (if keep? (cons (cons nm src) acc) acc))))))))
+
+;; Render a list of (frame-name . record) pairs (innermost/deepest first) to a
+;; backtrace string. record is a source vector #(ns name file line) -> "ns/name
+;; (file:line)", or 'ambiguous / #f -> the bare frame name. A run of the same
+;; frame-name collapses to one "name (xN)" line (deep recursion, or a hot fn a
+;; loop re-enters), and the number of distinct lines is capped.
+(define (jolt-render-recs recs)
+  (let ((port (open-output-string)))
+    (let loop ((rs recs) (shown 0))
+      (if (or (null? rs) (fx>=? shown 30))
+          (get-output-string port)
+          (let* ((p (car rs)) (frame-name (car p)) (r (cdr p)))
+            ;; count a maximal run of the same frame-name
+            (let run ((tail (cdr rs)) (cnt 1))
+              (if (and (pair? tail) (string=? (car (car tail)) frame-name))
+                  (run (cdr tail) (fx+ cnt 1))
+                  (begin
+                    (put-string port "    ")
+                    (if (vector? r)
+                        (let ((ns (vector-ref r 0)) (nm (vector-ref r 1))
+                              (file (vector-ref r 2)) (line (vector-ref r 3)))
+                          (put-string port ns) (put-string port "/") (put-string port nm)
+                          (when (string? file)
+                            (put-string port " (") (put-string port file)
+                            (put-string port ":") (put-string port (number->string line))
+                            (put-string port ")")))
+                        (put-string port frame-name))   ; 'ambiguous / unmapped: bare name
+                    (when (fx>? cnt 1)
+                      (put-string port " (x") (put-string port (number->string cnt)) (put-string port ")"))
+                    (put-char port #\newline)
+                    (loop tail (fx+ shown 1))))))))))
+
+;; Multi-line backtrace for an uncaught value. Two sources, in preference order:
+;;   1. The tail-frame history ring (rt.ss), when JOLT_TRACE enabled it — an
+;;      execution history of the runtime-compiled fns entered before the throw,
+;;      INCLUDING ones TCO erased from the live continuation. Most-recent first.
+;;   2. Otherwise the live continuation (jolt-frame-records) — the accurate but
+;;      TCO-truncated non-tail spine.
+;; Each frame maps to "ns/name (file:line)" when registered, else its bare name.
+;; #f when neither source yields a frame (the caller then prints just the location).
+;; The tail-frame history ring rendered as a backtrace, or #f when tracing is off /
+;; empty. A mapped frame is kept; else drop plumbing (same rule as the continuation
+;; path) so the two sources read consistently.
+(define (jolt-history-backtrace)
+  (let* ((hist (jolt-trace-snapshot))
+         (recs (let loop ((ns hist) (acc '()))
+                 (if (null? ns)
+                     (reverse acc)
+                     (let* ((nm (car ns)) (src (hashtable-ref source-registry nm #f)))
+                       (loop (cdr ns)
+                             (if (or src (not (srcreg-plumbing-name? nm)))
+                                 (cons (cons nm src) acc) acc)))))))
+    (and (pair? recs) (jolt-render-recs recs))))
 
-;; Multi-line backtrace for an uncaught value — "  ns/name (file:line)" for a
-;; mapped frame, the bare frame name for an ambiguous one — or #f when no jolt
-;; frame maps (the caller then prints just the top-level location). Capped to the
-;; innermost frames.
 (define (jolt-backtrace-string v)
-  (let ((k (jolt-error-continuation v)))
-    (and k
-         (let ((recs (jolt-frame-records k)))
-           (and (pair? recs)
-                (let ((port (open-output-string)))
-                  (let loop ((rs recs) (shown 0))
-                    (when (and (pair? rs) (fx<? shown 30))
-                      (let* ((p (car rs)) (frame-name (car p)) (r (cdr p)))
-                        (put-string port "    ")
-                        (if (vector? r)
-                            (let ((ns (vector-ref r 0)) (nm (vector-ref r 1))
-                                  (file (vector-ref r 2)) (line (vector-ref r 3)))
-                              (put-string port ns) (put-string port "/") (put-string port nm)
-                              (when (string? file)
-                                (put-string port " (") (put-string port file)
-                                (put-string port ":") (put-string port (number->string line))
-                                (put-string port ")")))
-                            (put-string port frame-name))   ; 'ambiguous: bare name
-                        (put-char port #\newline))
-                      (loop (cdr rs) (fx+ shown 1))))
-                  (get-output-string port)))))))
+  (or (jolt-history-backtrace)
+      (let ((k (jolt-error-continuation v)))
+        (and k
+             (let ((recs (jolt-frame-records k)))
+               (and (pair? recs) (jolt-render-recs recs)))))))
+
+;; Exposed for the REPL / nREPL error paths, which catch errors themselves instead
+;; of going through the uncaught reporter. Returns the "  trace:\n<frames>" block
+;; from the tail-frame HISTORY only — the live continuation in a REPL is just the
+;; REPL's own machinery — or nil when tracing is off (so a caller can when-let).
+(def-var! "jolt.host" "backtrace-string"
+  (lambda ()
+    (let ((bt (jolt-history-backtrace)))
+      (if bt (string-append "  trace:\n" bt) jolt-nil))))
 
 ;; Render an uncaught jolt throw (any value, not just a Chez condition) to a port:
 ;; an ex-info shows its message + ex-data (+ a host cause); anything else is

host/chez/stub/launcher.c

@@ -26,6 +26,12 @@ static int self_path(char *buf, uint32_t size) {
   /* _NSGetExecutablePath fills buf and reports the needed size on overflow. */
   return _NSGetExecutablePath(buf, &size);
 }
+#elif defined(_WIN32)
+#include <windows.h>
+static int self_path(char *buf, uint32_t size) {
+  DWORD n = GetModuleFileNameA(NULL, buf, size);
+  return (n == 0 || n >= size) ? -1 : 0;
+}
 #else
 #include <unistd.h>
 static int self_path(char *buf, uint32_t size) {

host/chez/transients.ss

@@ -86,7 +86,11 @@
                (if (fx<? i cnt) (begin (vector-set! out i (vector-ref buf i)) (loop (fx+ i 1)))
                    (make-pvec out)))))))
     ((map)
-     (let* ((ht (jolt-transient-buf t)) (cnt (hashtable-size ht)) (cap (jolt-transient-n t)))
+     (let* ((ht (jolt-transient-buf t)) (cnt (hashtable-size ht)) (cap (jolt-transient-n t))
+            ;; Clojure 1.13: a keyword-only map stays an array map up to 64 entries,
+            ;; so a keyword map built through a transient (into {} …) keeps insertion
+            ;; order to 64, matching the literal/assoc paths.
+            (cap (if (all-keywords? (jolt-transient-ord t)) (fxmax array-map-limit-kw cap) cap)))
        (if (fx>? cnt cap)
            ;; promoted past the array capacity: hash order
            (let ((m empty-pmap-hash))

jolt-core/clojure/core/00-syntax.clj

@@ -188,9 +188,23 @@
                      [false nil]
                      (if or-map (keys or-map) [])))
          amp? (fn* [x] (and (symbol? x) (= "&" (name x))))
+         ;; split a :keys/:syms/:strs name list at & into [sym bind?] pairs. Names
+         ;; before & bind normally (bind? true); names after & are declared-only
+         ;; (bind? false) — accepted keys (:keys) or required keys (:keys!), per
+         ;; CLJ-2961.
+         classify
+           (fn* [names]
+             (nth (reduce (fn* [st x]
+                            (if (amp? x)
+                              [(nth st 0) false]
+                              [(conj (nth st 0) [x (nth st 1)]) (nth st 1)]))
+                          [[] true] names)
+                  0))
          proc
            (fn* proc [pat init acc]
              (cond
+               ;; CLJ-2954: & is reserved for destructuring rest, never a binding.
+               (amp? pat) (throw (new IllegalArgumentException "Can't use & as a local binding"))
                (symbol? pat) (conj (conj acc pat) init)
                (vector? pat)
                  (let* [g (symbol (str (gensym)))
@@ -231,30 +245,45 @@
                         ;; group binds a :keys/:strs/:syms list. dnsp is the destructuring
                         ;; namespace from a qualified key like :ns/keys — it both prefixes
                         ;; the lookup key and overrides a bare symbol's namespace.
+                        ;; group binds a :keys/:strs/:syms list. checked? marks the
+                        ;; :keys!/:strs!/:syms! variants (CLJ-2961): lookups use req!
+                        ;; (throw on missing) instead of get. A pair is [sym bind?];
+                        ;; bind? false (names after &) is declared-only — for checked
+                        ;; groups it still runs req! (bound to a throwaway gensym) to
+                        ;; enforce the key, for unchecked groups it's a no-op.
                         group
-                          (fn* group [a names kind dnsp]
+                          (fn* group [a names kind dnsp checked?]
                             (if names
                                 (reduce
                                   ;; s is a symbol (a b) or a keyword (:a :b); name/
                                   ;; namespace handle both, so :keys [:major] binds
                                   ;; `major` looking up :major (str would keep the colon).
-                                  (fn* [aa s]
-                                    (let* [local (name s)
+                                  (fn* [aa pair]
+                                    (let* [s (nth pair 0)
+                                           bind? (nth pair 1)
+                                           local (name s)
                                            nsp (or (namespace s) dnsp)
                                            keyform (cond
                                                      (= kind :kw) (keyword (if nsp (str nsp "/" local) local))
                                                      (= kind :str) local
                                                      :else `(quote ~(symbol nsp local)))
-                                           fo (find-or or-map local)]
-                                      (conj (conj aa (symbol local))
-                                            (if (nth fo 0)
-                                              `(get ~gm ~keyform ~(nth fo 1))
-                                              `(get ~gm ~keyform)))))
-                                  a names)
+                                           fo (find-or or-map local)
+                                           lookup (cond
+                                                    checked? `(req! ~gm ~keyform)
+                                                    (nth fo 0) `(get ~gm ~keyform ~(nth fo 1))
+                                                    :else `(get ~gm ~keyform))]
+                                      (cond
+                                        bind?    (conj (conj aa (symbol local)) lookup)
+                                        checked? (conj (conj aa (symbol (str (gensym)))) lookup)
+                                        :else    aa)))
+                                  a (classify names))
                                 a))
-                        g1 (group base (get pat :keys) :kw nil)
-                        g2 (group g1 (get pat :strs) :str nil)
-                        g3 (group g2 (get pat :syms) :sym nil)]
+                        g1 (group base (get pat :keys)  :kw  nil false)
+                        g2 (group g1   (get pat :strs)  :str nil false)
+                        g3 (group g2   (get pat :syms)  :sym nil false)
+                        g4 (group g3   (get pat :keys!) :kw  nil true)
+                        g5 (group g4   (get pat :strs!) :str nil true)
+                        g6 (group g5   (get pat :syms!) :sym nil true)]
                    ;; remaining keys: a qualified :ns/keys|:ns/strs|:ns/syms groups under
                    ;; its namespace; any other keyword is skipped; a non-keyword is a
                    ;; nested binding pattern.
@@ -262,9 +291,12 @@
                              (if (keyword? k)
                                (let* [kn (name k) kns (namespace k)]
                                  (cond
-                                   (and kns (= kn "keys")) (group a (get pat k) :kw kns)
-                                   (and kns (= kn "strs")) (group a (get pat k) :str kns)
-                                   (and kns (= kn "syms")) (group a (get pat k) :sym kns)
+                                   (and kns (= kn "keys"))  (group a (get pat k) :kw  kns false)
+                                   (and kns (= kn "strs"))  (group a (get pat k) :str kns false)
+                                   (and kns (= kn "syms"))  (group a (get pat k) :sym kns false)
+                                   (and kns (= kn "keys!")) (group a (get pat k) :kw  kns true)
+                                   (and kns (= kn "strs!")) (group a (get pat k) :str kns true)
+                                   (and kns (= kn "syms!")) (group a (get pat k) :sym kns true)
                                    :else a))
                                ;; a direct binding {x :x}: apply its :or default
                                ;; (keyed by the local symbol) when the key is absent.
@@ -273,7 +305,7 @@
                                            `(get ~gm ~(get pat k) ~(nth fo 1))
                                            `(get ~gm ~(get pat k)))
                                        a))))
-                           g3 (keys pat)))
+                           g6 (keys pat)))
                :else (throw (str "unsupported destructuring pattern: " (pr-str pat)))))
          ploop
            (fn* ploop [i acc]

jolt-core/clojure/core/21-coll.clj

@@ -66,9 +66,10 @@
    \backspace "backspace" \space "space"})
 (defn char-name-string [c] (get char-name-strings c))
 
-;; Random selection over the host rand primitives.
+;; Random selection over the host rand primitives — the reference shape:
+;; nth directly (nil returns nil via RT.nth; a set throws like the JVM).
 (defn rand-nth [coll]
-  (let [v (vec coll)] (nth v (rand-int (count v)))))
+  (nth coll (rand-int (count coll))))
 
 (defn random-sample
   ([prob] (filter (fn [_] (< (rand) prob))))

jolt-core/clojure/core/22-coll.clj

@@ -89,6 +89,21 @@
              (recur nxt (next ks))))
          m)))))
 
+(defn req!
+  "Returns the value mapped to key k in map m, like `get`, but throws
+  IllegalArgumentException when k is not present. Unlike `get`, does not nil-pun:
+  a key present with a nil value returns nil, an absent key throws. The primitive
+  behind checked-keys destructuring (:keys! / :syms! / :strs!)."
+  {:added "1.13"}
+  [m k]
+  ;; a fresh map is its own identity, so a present-but-nil value is distinguished
+  ;; from an absent key (same trick as get-in's sentinel).
+  (let [sentinel (hash-map)
+        v (get m k sentinel)]
+    (if (identical? sentinel v)
+      (throw (new IllegalArgumentException (str "Expected key: " k)))
+      v)))
+
 ;; find-based, so nil RESULTS are cached too; args canonicalize as a collection key.
 (defn memoize [f]
   (let [mem (atom (hash-map))]

jolt-core/jolt/backend_scheme.clj

@@ -172,6 +172,14 @@
 (def var-cache? (atom false))
 (defn set-var-cache! [on] (reset! var-cache? on))
 
+;; Opt-in tail-frame history (JOLT_TRACE): emit a (jolt-trace-push! "name") at the
+;; head of every named fn body, so an entry records the frame into the runtime ring
+;; buffer (rt.ss) and a TCO-elided frame still shows in an error's backtrace. OFF
+;; during the seed mint and `jolt build` (byte-determinism + no runtime cost);
+;; compile-eval.ss turns it on for runtime-eval'd user code when JOLT_TRACE is set.
+(def trace-frames? (atom false))
+(defn set-trace-frames! [on] (reset! trace-frames? on))
+
 ;; A direct-link Scheme binding name for a var. The fqn maps to a unique identifier
 ;; jv$<ns>$<name>; chars that break a Scheme identifier or the `$` separator are
 ;; escaped so distinct vars never collide.
@@ -191,6 +199,13 @@
 ;; recursion auto-restores them (no manual save/restore, no throw-leak).
 (def ^:dynamic *recur-target* nil)
 (def ^:dynamic *known-procs* #{})
+;; True while emitting a node in TAIL position. Only used, in trace mode, to mark a
+;; tail call so the runtime routes its callee into the current history rib instead
+;; of a new one (rt.ss). It never affects semantics — a wrong value only mislabels
+;; a debug trace line — so partial propagation is safe. `emit` (the wrapper below)
+;; clears it by default; the tail-transparent forms (fn body, if/do/let/loop) pass
+;; it to their tail child. Default false so a top-level form is treated non-tail.
+(def ^:dynamic *tail?* false)
 
 (def ^:private gensym-counter (atom 0))
 (defn- fresh-label [prefix] (str prefix (swap! gensym-counter inc)))
@@ -253,6 +268,17 @@
     (if (or (contains? scheme-reserved s) (contains? bare-native-names s)) (str "_" s) s)))
 
 (declare emit)
+(declare emit*)
+;; Ops that pass tail position through to a child (the child can itself be a tail
+;; call): if/do carry it to their tail branch/last form, let/loop to their body,
+;; and invoke reads it to decide whether the call is tail. Every other op's
+;; children are non-tail, so `emit` clears *tail?* before dispatching them — that
+;; way a stray true can't leak into, say, a call sitting in a vector literal.
+(def ^:private tail-transparent-ops #{:if :do :let :loop :invoke})
+(defn emit [node]
+  (if (and *tail?* (not (tail-transparent-ops (:op node))))
+    (binding [*tail?* false] (emit* node))
+    (emit* node)))
 
 ;; A Chez string literal. Every char outside printable ASCII becomes a
 ;; codepoint hex escape \x<cp>; ; the named escapes (\n \t \r \" \\) match what
@@ -413,9 +439,10 @@
 ;; letfn lowers to a :let flagged :letrec (mutually-recursive named local fns):
 ;; Scheme `letrec*` binds them so each sees its siblings. A plain let uses let*.
 (defn- emit-let [node]
-  (let [kw (if (:letrec node) "letrec*" "let*")]
-    (str "(" kw " (" (str/join " " (map emit-binding (:bindings node))) ") "
-         (emit (:body node)) ")")))
+  (let [kw (if (:letrec node) "letrec*" "let*")
+        ;; bindings are non-tail; the body inherits the let's tail position
+        binds (binding [*tail?* false] (str/join " " (mapv emit-binding (:bindings node))))]
+    (str "(" kw " (" binds ") " (emit (:body node)) ")")))
 
 (defn- emit-loop [node]
   (let [label (fresh-label "loop")
@@ -423,9 +450,10 @@
         names (map #(munge-name (nth % 0)) pairs)
         ;; inits evaluate in the OUTER scope (recur-target unchanged) and, like
         ;; Clojure loop/let, SEQUENTIALLY — wrap a let* around the named let.
-        inits (map #(emit (nth % 1)) pairs)
+        inits (binding [*tail?* false] (mapv #(emit (nth % 1)) pairs))
         seq-bs (str/join " " (map (fn [n i] (str "(" n " " i ")")) names inits))
         rebinds (str/join " " (map (fn [n] (str "(" n " " n ")")) names))
+        ;; the loop body inherits the loop's tail position
         body (binding [*recur-target* label] (emit (:body node)))]
     (str "(let* (" seq-bs ") (let " label " (" rebinds ") " body "))")))
 
@@ -486,7 +514,11 @@
         params (map munge-name orig)
         restp (when-let [r (:rest a)] (munge-name r))
         label (fresh-label "fnrec")
-        body (binding [*recur-target* label] (emit (:body a)))
+        ret (:ret-nhint a)
+        ;; the body is the fn's tail position — UNLESS a ^double/^long return hint
+        ;; wraps it in a coercion below, which puts the body back in non-tail.
+        body-tail? (not (or (= ret :double) (= ret :long)))
+        body (binding [*recur-target* label *tail?* body-tail?] (emit (:body a)))
         paramlist (cond
                     (and restp (empty? params)) restp
                     restp (str "(" (str/join " " params) " . " restp ")")
@@ -511,6 +543,16 @@
         self (when-let [nm (:name node)] (munge-name nm))
         clauses (binding [*known-procs* (if self (conj *known-procs* self) *known-procs*)]
                   (mapv emit-arity-clause arities))
+        ;; trace mode: record this frame on entry (before the body), so a frame
+        ;; the body then tail-calls away is still in the ring at throw time. A
+        ;; `recur` re-enters via the named-let, not the lambda, so a tight loop
+        ;; records once, not per iteration.
+        clauses (if (and @trace-frames? self)
+                  (mapv (fn [c] [(nth c 0)
+                                 (str "(begin (jolt-trace-push! " (chez-str-lit self) ") "
+                                      (nth c 1) ")")])
+                        clauses)
+                  clauses)
         lambda (if (= 1 (count clauses))
                  (let [c (first clauses)] (str "(lambda " (nth c 0) " " (nth c 1) ")"))
                  (str "(case-lambda "
@@ -573,8 +615,31 @@
             (= (nth shape i) kw) i
             :else (recur (inc i))))))
 
+;; A plain Scheme application: (callee op ...).
+(defn- plain-call [callee operand-strs]
+  (str "(" callee (if (seq operand-strs) (str " " (str/join " " operand-strs)) "") ")"))
+;; A tail call in trace mode. Force-bind the operands to temps FIRST (so any
+;; operand whose own evaluation records a trace entry runs before our mark), THEN
+;; set the tail mark, THEN apply — the callee's entry prologue consumes the mark
+;; with nothing in between, so it can't be clobbered. Still a tail call: the let*'s
+;; last form is the application, so TCO is preserved.
+(defn- tail-marked-call [callee operand-strs]
+  (let [tmps (mapv (fn [_] (fresh-label "_tt$")) operand-strs)
+        binds (str/join " " (map (fn [t a] (str "(" t " " a ")")) tmps operand-strs))]
+    (str "(let* (" binds ") (jolt-trace-mark! #t) " (plain-call callee tmps) ")")))
+;; Emit a call, tail-marked when we're in tail position and tracing is on; a plain
+;; application otherwise. The mark is consumed by the callee's entry prologue —
+;; direct calls (:local known-proc, direct-link) always have one; a jolt-invoke
+;; call usually reaches one but not always (see the best-effort note in rt.ss).
+(defn- emit-call [tail? callee operand-strs]
+  (if (and @trace-frames? tail?)
+    (tail-marked-call callee operand-strs)
+    (plain-call callee operand-strs)))
+
 (defn- emit-invoke [node]
-  (let [fnode (:fn node)
+  (let [tail? *tail?*]           ; capture: children below emit non-tail
+   (binding [*tail?* false]
+    (let [fnode (:fn node)
         arg-nodes (:args node)
         args (mapv emit arg-nodes)
         nop (native-op fnode (count args))
@@ -586,8 +651,7 @@
         ;; order [callee & args] together when ordering is observable.
         invoke (fn []
                  (ordered-call (cons fnode arg-nodes) (cons (emit fnode) args)
-                               (fn [[f & as]]
-                                 (str "(jolt-invoke " f (if (seq as) (str " " (str/join " " as)) "") ")"))))]
+                               (fn [operands] (emit-call tail? "jolt-invoke" operands))))]
     (cond
       ;; devirtualized protocol call: the inference proved the receiver (arg 0) is
       ;; one record type, so resolve the impl by that static tag instead of routing
@@ -662,8 +726,7 @@
       ;; holds an arbitrary IFn -> dynamic dispatch.
       (= :local (:op fnode))
       (if (*known-procs* (munge-name (:name fnode)))
-        (order-args (fn [as] (str "(" (munge-name (:name fnode))
-                                  (if (seq as) (str " " (str/join " " as)) "") ")")))
+        (order-args (fn [as] (emit-call tail? (munge-name (:name fnode)) as)))
         (invoke))
       ;; closed-world direct call: the callee var is an app fn def already emitted
       ;; with a Scheme binding — apply it directly, no var lookup, no jolt-invoke.
@@ -672,8 +735,7 @@
       ;; below (which still uses the direct binding as the invoke target).
       (and (= :var (:op fnode)) (direct-linkable? (:ns fnode) (:name fnode))
            (direct-link-fn? (:ns fnode) (:name fnode)))
-      (order-args (fn [as] (str "(" (dl-name (:ns fnode) (:name fnode))
-                                (if (seq as) (str " " (str/join " " as)) "") ")")))
+      (order-args (fn [as] (emit-call tail? (dl-name (:ns fnode) (:name fnode)) as)))
       ;; a late-bound :var call head can hold a procedure OR a non-applicable
       ;; value the RT dispatches (multimethod, keyword/coll IFn) — route via
       ;; jolt-invoke (transparent for a procedure).
@@ -681,7 +743,7 @@
       (invoke)
       ;; a computed callee can yield ANY IFn — route through jolt-invoke.
       :else
-      (invoke))))
+      (invoke))))))
 
 ;; try/catch/finally. throw raises a Chez condition wrapping the jolt value
 ;; (jolt-throw = Scheme `raise` of a &jolt-throw condition); catch lowers to
@@ -728,7 +790,22 @@
        (returns-scheme-bool? (:body node) bools'))
      :else false)))
 
-(defn emit [node]
+;; In trace mode, a fn def also registers its source so the tail-frame history maps
+;; the recorded frame-name to "ns/name (file:line)" instead of a bare name. Keyed by
+;; the SAME munged name the entry push records (emit-fn's letrec self-binding = the
+;; fn's own name). Returns "" when off / not a positioned fn def, so trace-off output
+;; (seed mint, `jolt build`) is byte-identical. Direct-link builds already register
+;; via emit-def-cached; this covers the open-world eval path.
+(defn- trace-source-reg [node]
+  (let [init (:init node) pos (:pos node)]
+    (if (and @trace-frames? (= :fn (:op init)) (:name init) pos)
+      (str " (jolt-register-source! " (chez-str-lit (munge-name (:name init))) " "
+           (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
+           (if (:file pos) (chez-str-lit (:file pos)) "jolt-nil") " "
+           (or (:line pos) 0) ")")
+      "")))
+
+(defn emit* [node]
   (case (:op node)
     :const (emit-const (:val node))
     :local (munge-name (:name node))
@@ -776,11 +853,14 @@
     :host-new (str "(host-new " (chez-str-lit (:class node))
                    (let [args (map emit (:args node))]
                      (if (empty? args) "" (str " " (str/join " " args)))) ")")
+    ;; the test is non-tail; then/else inherit the if's tail position
     :if (let [test (:test node)
-              t (if (returns-scheme-bool? test) (emit test)
-                    (str "(jolt-truthy? " (emit test) ")"))]
+              t (binding [*tail?* false]
+                  (if (returns-scheme-bool? test) (emit test)
+                      (str "(jolt-truthy? " (emit test) ")")))]
           (str "(if " t " " (emit (:then node)) " " (emit (:else node)) ")"))
-    :do (str "(begin " (str/join " " (map emit (:statements node)))
+    ;; non-last statements are non-tail; the ret inherits the do's tail position
+    :do (str "(begin " (binding [*tail?* false] (str/join " " (mapv emit (:statements node))))
              (if (empty? (:statements node)) "" " ") (emit (:ret node)) ")")
     :invoke (emit-invoke node)
     ;; collection literals -> rt constructors (collections.ss). Elements are
@@ -824,15 +904,17 @@
     :fn (emit-fn node)
     ;; (def name) with no init (declare): reserve the cell. A def with non-empty
     ;; reader metadata lowers to def-var-with-meta! (ported in a later increment).
-    :def (cond
-           (:no-init node)
-           (str "(declare-var! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) ")")
-           (jmeta-nonempty? (:meta node))
-           (str "(def-var-with-meta! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
-                (emit-with-cells #(emit (:init node))) " " (emit-def-meta node) ")")
-           :else
-           (str "(def-var! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
-                (emit-with-cells #(emit (:init node))) ")"))
+    :def (let [reg (trace-source-reg node)
+               d (cond
+                   (:no-init node)
+                   (str "(declare-var! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) ")")
+                   (jmeta-nonempty? (:meta node))
+                   (str "(def-var-with-meta! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
+                        (emit-with-cells #(emit (:init node))) " " (emit-def-meta node) ")")
+                   :else
+                   (str "(def-var! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
+                        (emit-with-cells #(emit (:init node))) ")"))]
+           (if (= reg "") d (str "(begin " d reg ")")))
     (throw (ex-info (str "emit: op not yet ported / unhandled: " (pr-str (:op node))) {}))))
 
 ;; ^:dynamic / ^:redef on a def opts it out of direct-linking: it stays redefinable,

jolt-core/jolt/deps.clj

@@ -66,6 +66,10 @@
       (if-let [root (:deps/root spec)] (str checkout "/" root) checkout))
     (:jolt/module spec)
     (do (warn "skipping janet dependency " coord " (:jolt/module is obsolete on Chez)") nil)
+    ;; jolt IS Clojure — a dependency on org.clojure/clojure is satisfied
+    ;; intrinsically, so skip it silently rather than warning about the (unusable)
+    ;; :mvn/version coordinate.
+    (= coord 'org.clojure/clojure) nil
     :else
     (do (warn "skipping unsupported coordinate " coord " " (pr-str spec)) nil)))
 

jolt-core/jolt/main.clj

@@ -8,6 +8,8 @@
 
 (defn- project-dir [] (or (jolt.host/getenv "JOLT_PWD") "."))
 
+(defn- version [] (jolt.host/jolt-version))
+
 (defn- current-platform []
   (let [os (str/lower-case (or (System/getProperty "os.name") ""))]
     (cond (str/includes? os "mac") :darwin
@@ -145,7 +147,10 @@
   ;; loaded — same context a run gets, so (require '[some.lib]) works in the REPL.
   (try (apply-project! (deps/resolve-project (project-dir)))
        (catch :default _ nil))
-  (println ";; jolt repl — :repl/quit or ^D to exit")
+  ;; REPL-driven development: trace by default so an uncaught error in evaluated
+  ;; code shows a tail-frame backtrace, no JOLT_TRACE needed (JOLT_TRACE=0 opts out).
+  (jolt.host/enable-trace!)
+  (println (str ";; jolt " (version) " repl — :repl/quit or ^D to exit"))
   (loop []
     (let [form (repl-read-form)]
       (when form
@@ -158,7 +163,9 @@
                  (catch :default e
                    (println "error:" (or (ex-message e)
                                          (try ((resolve 'jolt.host/condition-message) e) (catch :default _ nil))
-                                         (pr-str e)))))
+                                         (pr-str e)))
+                   (when-let [bt (jolt.host/backtrace-string)]
+                     (print bt))))
             (recur)))))))
 
 ;; A deps.edn :tasks entry: a string is a shell command; a map is {:main-opts …}.
@@ -294,7 +301,9 @@
         (when stop (stop))))))
 
 (defn- usage []
+  (println (str "jolt " (version)))
   (println "usage: jolt <command> [args]")
+  (println "  -e EXPR                evaluate EXPR and print the result")
   (println "  run -m NS [args]       resolve deps.edn, load NS, call its -main")
   (println "  run FILE               load a Clojure file")
   (println "  build -m NS [-o OUT] [--opt|--dev] [--direct-link] [--tree-shake] [--dynamic]  compile a standalone binary")
@@ -304,6 +313,7 @@
   (println "  --nrepl-server [port]  start an nREPL server (default 7888) for editors")
   (println "  path                   print the resolved source roots")
   (println "  <task>                 run a deps.edn :tasks entry")
+  (println "  --version              print the jolt version")
   (println "  --help                 print this message"))
 
 (defn -main [& args]
@@ -312,6 +322,7 @@
       (nil? cmd)                  (usage)
       (= cmd "--help")            (usage)
       (= cmd "-h")                (usage)
+      (#{"--version" "-V"} cmd)   (println (str "jolt " (version)))
       (= cmd "run")               (cmd-run more)
       (= cmd "repl")              (repl)
       (= cmd "--nrepl-server")    (nrepl more)

jolt-core/jolt/nrepl.clj

@@ -21,25 +21,66 @@
             [jolt.ffi :as ffi]))
 
 ;; --- sockets (loopback server) ---------------------------------------------
-;; Load libc (the running process's symbols) BEFORE the foreign-fn bindings below
-;; — defcfn resolves the C entry point when the def is evaluated (at ns load), so
-;; the socket symbols must already be available.
-(ffi/load-library)
+(def ^:private os-name
+  (str/lower-case (or (System/getProperty "os.name") "")))
+(def ^:private macos?   (str/includes? os-name "mac"))
+(def ^:private windows? (str/includes? os-name "win"))
+
+;; Load the library that provides the socket symbols BEFORE the foreign-fn
+;; bindings below — defcfn resolves the C entry point when the def is evaluated
+;; (at ns load), so the symbols must already be available. POSIX: the running
+;; process's own libc symbols. Windows: the Winsock DLL (ws2_32), whose symbols
+;; are NOT in joltc.exe's export table even though it's linked in — without this
+;; explicit load, (ffi/defcfn c-socket "socket" ...) fails at load with
+;; "no entry for socket".
+(if windows?
+  (ffi/load-library "ws2_32.dll")
+  (ffi/load-library))
+
+;; A socket is an int fd on POSIX; on Win64 it's a SOCKET (uintptr_t) handle, but
+;; those are small kernel handle values that round-trip through :int, and the
+;; INVALID_SOCKET error sentinel (~0) reads back as -1 — so the fd checks below
+;; work unchanged on both.
 (ffi/defcfn c-socket     "socket"     [:int :int :int] :int)
 (ffi/defcfn c-bind       "bind"       [:int :pointer :int] :int)
 (ffi/defcfn c-listen     "listen"     [:int :int] :int)
 (ffi/defcfn c-setsockopt "setsockopt" [:int :int :int :pointer :int] :int)
-  (ffi/defcfn c-accept     "accept"     [:int :pointer :pointer] :int :blocking)
-  (ffi/defcfn c-recv       "recv"       [:int :pointer :size_t :int] :ssize_t :blocking)
-  (ffi/defcfn c-send       "send"       [:int :pointer :size_t :int] :ssize_t :blocking)
-(ffi/defcfn c-close      "close"      [:int] :int)
+(ffi/defcfn c-accept     "accept"     [:int :pointer :pointer] :int :blocking)
+
+;; recv/send and the socket-close call differ by platform. Winsock's recv/send
+;; take an int length and return int (not ssize_t), and a socket is closed with
+;; closesocket, not close. A symbol that exists on only one OS (closesocket on
+;; Windows, close on POSIX) can only be bound there, so these live in the taken
+;; platform branch — jolt interns the vars from both branches at analysis time,
+;; so later references resolve either way.
+(if windows?
+  (do
+    (ffi/defcfn c-recv  "recv"        [:int :pointer :int :int] :int :blocking)
+    (ffi/defcfn c-send  "send"        [:int :pointer :int :int] :int :blocking)
+    (ffi/defcfn c-close "closesocket" [:int] :int)
+    ;; Winsock must be initialized once per process before any socket call.
+    (ffi/defcfn c-wsastartup "WSAStartup" [:int :pointer] :int))
+  (do
+    (ffi/defcfn c-recv  "recv"  [:int :pointer :size_t :int] :ssize_t :blocking)
+    (ffi/defcfn c-send  "send"  [:int :pointer :size_t :int] :ssize_t :blocking)
+    (ffi/defcfn c-close "close" [:int] :int)))
 
 (def ^:private AF-INET 2)
 (def ^:private SOCK-STREAM 1)
-(def ^:private macos?
-  (str/includes? (str/lower-case (or (System/getProperty "os.name") "")) "mac"))
-(def ^:private sol-socket (if macos? 0xffff 1))
-(def ^:private so-reuse   (if macos? 4 2))
+;; SOL_SOCKET / SO_REUSEADDR: 0xffff / 4 on macOS and Windows, 1 / 2 on Linux.
+(def ^:private sol-socket (if (or macos? windows?) 0xffff 1))
+(def ^:private so-reuse   (if (or macos? windows?) 4 2))
+
+;; Initialize Winsock (a no-op off Windows). WSAStartup is refcounted and must
+;; precede any socket call; WSADATA is ~408 bytes on x64, so 512 is ample.
+(defn- ensure-winsock! []
+  (when windows?
+    (let [wsadata (ffi/alloc 512)]
+      (try
+        (let [r (c-wsastartup 0x0202 wsadata)]
+          (when-not (zero? r)
+            (throw (ex-info (str "WSAStartup failed: " r) {}))))
+        (finally (ffi/free wsadata))))))
 
 (defn- make-sockaddr [port]
   (let [sa (ffi/alloc 16)]
@@ -53,7 +94,7 @@
     sa))
 
 (defn- listen-socket [port]
-  (ffi/load-library)                                         ; libc process symbols
+  (ensure-winsock!)                                          ; no-op off Windows
   (let [fd (c-socket AF-INET SOCK-STREAM 0)]
     (when (neg? fd) (throw (ex-info "socket() failed" {})))
     (let [opt (ffi/alloc 4)] (ffi/write opt :int 0 1) (c-setsockopt fd sol-socket so-reuse opt 4) (ffi/free opt))
@@ -147,7 +188,10 @@
               (try (when (and ns-str (not (str/blank? ns-str)) (find-ns (symbol ns-str)))
                      (in-ns (symbol ns-str)))
                    (reset! result (load-string code))
-                   (catch :default e (reset! err (err-msg e)))))]
+                   (catch :default e
+                     (reset! err (str (err-msg e)
+                                      (when-let [bt (jolt.host/backtrace-string)]
+                                        (str "\n" bt)))))))]
     {:value (when (nil? @err) (pr-str @result))
      :out out
      :ns (str (ns-name *ns*))
@@ -236,11 +280,17 @@
   no-op."
   ([port] (start port nil))
   ([port middleware]
+   ;; An nREPL session is REPL-driven development: trace by default so an uncaught
+   ;; error in code evaluated over the connection shows a tail-frame backtrace, with
+   ;; no JOLT_TRACE needed. Covers both `--nrepl-server` and an app that starts its
+   ;; own server under `-M:run` (reload a namespace to trace already-loaded code).
+   (jolt.host/enable-trace!)
    (let [handler (build-handler (resolve-middleware (or middleware [])))
          fd (listen-socket port)                  ; throws on bind/listen failure
          stopped (atom false)]
      (try (spit ".nrepl-port" (str port)) (catch :default _ nil))
-     (println (str "nREPL server started on port " port " (127.0.0.1) — .nrepl-port written"))
+     (println (str "jolt " (jolt.host/jolt-version) " nREPL server started on port "
+                   port " (127.0.0.1) — .nrepl-port written"))
      (when (seq middleware) (println (str ";; middleware: " (str/join " " middleware))))
      (println ";; connect your editor; ^C to stop")
       (future

test/chez/README.md

@@ -7,7 +7,7 @@ test` from the repo root.
 
 ## The spec corpus
 
-`corpus.edn` is the contract: ~2920 rows `{:suite :label :expected :actual}`, with
+`corpus.edn` is the contract: ~3570 rows `{:suite :label :expected :actual :portability}`, with
 `:expected` sourced from reference JVM Clojure by `test/conformance/regen-corpus.clj`.
 It is frozen (the canonical source) — add or change cases here, then re-source the
 answers with `regen-corpus.clj` and re-certify with `test/conformance/certify.clj`.
@@ -22,7 +22,7 @@ answers with `regen-corpus.clj` and re-certify with `test/conformance/certify.cl
 
       chez --script host/chez/run-corpus.ss
       JOLT_CORPUS_LIMIT=200 …            # every-Nth stride, fast iteration
-      JOLT_CHEZ_ZJ_FLOOR=N …            # override the floor (default 2678)
+      JOLT_CHEZ_ZJ_FLOOR=N …            # override the floor (see run-corpus.ss)
 
 - `run-unit.ss` — host-specific unit cases (`test/chez/unit.edn`) that aren't in the
   JVM-portable corpus: dot-forms, java statics, io, reader, walk, vars/namespaces,

test/chez/cts-known-failures.txt

@@ -23,7 +23,6 @@ clojure.core-test.plus 11 0
 clojure.core-test.plus-squote 11 0
 clojure.core-test.pos-int-qmark 1 0
 clojure.core-test.quot 25 0
-clojure.core-test.rand-nth 0 1
 clojure.core-test.realized-qmark 1 0
 clojure.core-test.rem 16 0
 clojure.core-test.remove-watch 0 1

test/chez/unit.edn

@@ -576,4 +576,26 @@
   {:suite "deftype-method" :expr "(do (defprotocol P (m [_ o])) (defrecord R [n] P (m [_ _] n)) (m (->R 5) :x))" :expected "5"}
   {:suite "deftype-method" :expr "(do (defprotocol P2 (m2 [_ o])) (deftype T [n] P2 (m2 [_ _] n)) (m2 (->T 7) :x))" :expected "7"}
   {:suite "protocol-host" :expr "(do (defprotocol Q (e [_])) (extend-protocol Q clojure.lang.Var (e [_] :var)) [(satisfies? Q (var map)) (e (var map))])" :expected "[true :var]"}
+
+  ;; Clojure 1.13 (1.13.0-alpha1) parity. Ahead of the JVM 1.12.5 the corpus
+  ;; certifies against, so these live here rather than as certified corpus rows.
+  {:suite "clj-1.13 req!" :expr "(req! {:a 1} :a)" :expected "1"}
+  {:suite "clj-1.13 req!" :expr "(req! [10 20 30] 1)" :expected "20"}
+  {:suite "clj-1.13 req!" :expr "(nil? (req! {:a nil} :a))" :expected "true"}
+  {:suite "clj-1.13 req!" :expr "(req! {:a 1} :b)" :expected :throws}
+  {:suite "clj-1.13 amp-binding" :expr "(let [& 42] &)" :expected :throws}
+  {:suite "clj-1.13 amp-binding" :expr "(loop [& 42] &)" :expected :throws}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys! [a b]} {:a 1 :b 2}] [a b])" :expected "[1 2]"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys! [a b]} {:a 1}] [a b])" :expected :throws}
+  {:suite "clj-1.13 checked-keys" :expr "(nil? (let [{:keys! [a]} {:a nil}] a))" :expected "true"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:strs! [a]} {\"a\" 5}] a)" :expected "5"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys! [a & b]} {:a 1 :b 2}] a)" :expected "1"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys! [a & b]} {:a 1}] a)" :expected :throws}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys [a & b]} {:a 1 :b 2}] a)" :expected "1"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:foo/keys! [a]} {:foo/a 7}] a)" :expected "7"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:foo/keys! [a]} {}] a)" :expected :throws}
+  {:suite "clj-1.13 array-map-64" :expr "(keys {:a 1 :b 2 :c 3 :d 4 :e 5 :f 6 :g 7 :h 8 :i 9 :j 10})" :expected "(:a :b :c :d :e :f :g :h :i :j)"}
+  {:suite "clj-1.13 array-map-64" :expr "(= (map (fn [i] (keyword (str \"k\" i))) (range 20)) (keys (into {} (map (fn [i] [(keyword (str \"k\" i)) i]) (range 20)))))" :expected "true"}
+  {:suite "clj-1.13 array-map-64" :expr "(= (map (fn [i] (keyword (str \"k\" i))) (range 64)) (keys (reduce (fn [m i] (assoc m (keyword (str \"k\" i)) i)) {} (range 64))))" :expected "true"}
+  {:suite "clj-1.13 array-map-64" :expr "(= (map (fn [i] (keyword (str \"k\" i))) (range 65)) (keys (into {} (map (fn [i] [(keyword (str \"k\" i)) i]) (range 65)))))" :expected "false"}
 ]

test/conformance/SPEC.md

@@ -10,7 +10,7 @@ read one data file, run each case, compare, report.
 
 | File | Role | Generated by |
 |------|------|--------------|
-| `test/chez/corpus.edn` | **The spec.** ~2900 cases of `{:suite :label :expected :actual}`, `:expected` **sourced from reference JVM Clojure**. | `test/conformance/regen-corpus.clj` |
+| `test/chez/corpus.edn` | **The spec.** ~3570 cases of `{:suite :label :expected :actual :portability}`, `:expected` **sourced from reference JVM Clojure**. | `test/conformance/regen-corpus.clj` |
 | `test/conformance/profile.edn` | Per-case **feature classification** — which non-portable cases need which host capability. | `certify.clj --profile` |
 | `test/conformance/known-divergences.edn` | The few rows whose JVM value is an opaque host object that can't round-trip to readable source (Java arrays/transients/atoms/beans/proxies print as `#object[..@addr]`), so the corpus keeps jolt's value. | `regen-corpus.clj` leftovers, hand-checked |
 | `test/conformance/regen-corpus.clj` | Sources every `:expected` from reference **JVM Clojure** in one process. | — |
@@ -24,11 +24,17 @@ the canonical, frozen contract**: it is what every runtime consumes, what
 ## Row schema
 
 ```edn
-{:suite    "numbers / arithmetic"      ; grouping; "<suite> :: <label>" is the case id
- :label    "integer add"               ; unique within a suite
- :actual   "(+ 1 2)"                    ; Clojure source to evaluate
- :expected "3"}                         ; Clojure source whose value it must equal,
+{:suite       "numbers / arithmetic"   ; grouping; "<suite> :: <label>" is the case id
+ :label       "integer add"            ; unique within a suite
+ :actual      "(+ 1 2)"                 ; Clojure source to evaluate
+ :expected    "3"                       ; Clojure source whose value it must equal,
                                         ; or the keyword :throws
+ :portability :common}                  ; :common = portable Clojure any dialect
+                                        ; must satisfy; :jvm = exercises host
+                                        ; interop (java.*/clojure.lang.* classes,
+                                        ; dot forms, ctors, statics, arrays,
+                                        ; proxy/bean) — skip on a non-JVM-shaped
+                                        ; dialect
 ```
 
 - `[:suite :label]` is the **canonical, unique case id** (the generator
@@ -48,8 +54,8 @@ the canonical, frozen contract**: it is what every runtime consumes, what
 Historically every `:expected` was hand-written. `certify.clj` removes that
 weakness: it evaluates every `:actual` (and `:expected`) on **JVM Clojure** in a
 fresh `user` namespace and checks jolt's `:expected` against what real Clojure
-produces. Of ~2740 vanilla-certifiable rows, **>2730 match reference Clojure
-exactly**. The rest are classified (see below) — none are silently wrong.
+produces. Of ~3400 vanilla-certifiable rows, **all but ~26 allowlisted rows
+match reference Clojure exactly**. The rest are classified (see below) — none are silently wrong.
 
 ```sh
 clojure -M test/conformance/certify.clj                                  # gate
@@ -237,8 +243,7 @@ documented model divergence — nothing in the baseline is an unexplained bug:
 - **vec of an array copies**: the reference ADOPTS an Object array (mutating
   the array mutates the vector); jolt copies — immutable semantics win over
   the implementation leak (`vec` namespace, one row).
-- **eval of JVM shapes** (`rand-nth`/`eval` residue): rows needing JVM-only
-  evaluation shapes (e.g. evaluating a Java array literal).
+
 
 A future change that makes any of these rows pass will fail the cts gate as
 STALE, forcing this section and the baseline to be updated together.

test/conformance/regen-corpus.clj

@@ -99,11 +99,12 @@
       [row :kept])))
 
 ;; --- corpus writer (preserves the one-row-per-line layout) -------------------
-(defn row-str [{:keys [suite label expected actual]}]
+(defn row-str [{:keys [suite label expected actual portability]}]
   (str "  {:suite " (pr-str suite)
        " :label " (pr-str label)
        " :expected " (if (= expected :throws) ":throws" (pr-str expected))
-       " :actual " (pr-str actual) "}"))
+       " :actual " (pr-str actual)
+       (when portability (str " :portability " portability)) "}"))
 
 (defn -main [& _]
   (let [corpus (edn/read-string (slurp corpus-path))