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Clojure stack traces via source registry + native frame walk

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A direct-link build emits (jolt-register-source! short-name ns name file line)
once per fn def — at definition time, so zero per-call cost. On an uncaught
error the reporter walks Chez's native continuation frames (jolt-throw captures
the live continuation via call/cc; host conditions carry their own
&continuation), maps each frame's procedure name through the registry, and
prints a Clojure backtrace 'ns/name (file:line)'. Wired into both the cli and a
built binary's launcher.

Frames are keyed by the short munged fn name Chez actually reports (emit-fn's
letrec self-binding), not jv$ns$name; a cross-namespace collision degrades to
the bare frame name rather than a wrong attribution. The analyzer carries the
original form's position through defn macroexpansion onto the def node.

Calling a non-fn now throws a catchable ClassCastException (via jolt-throw)
naming the operator, instead of a raw Chez error.

Caveats (documented in source-registry.ss): names map only in direct-link/AOT
closed-world builds — the open-world -e/repl/run path falls back to the
top-level location; and pervasive TCO erases tail-call frames, so a mapped
trace shows only the non-tail spine. JOLT_DEBUG_FRAMES dumps raw frame names.

Re-mint (analyzer + backend); prelude byte-identical (direct-link off during
mint). Corpus rows certified, build-smoke asserts the trace.
This commit is contained in:
Yogthos 2026-06-25 21:49:11 -04:00
parent 9bf3d1c80e
commit 57bab5d409
12 changed files with 288 additions and 105 deletions
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12
host/chez/rt.ss
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@ -35,7 +35,13 @@
;; throw raises the jolt value RAW (no envelope);
;; catch (emitted as `guard`) binds it directly. Chez `raise` accepts any
;; object, so a thrown number/map/ex-info all work; uncaught -> non-zero exit.
(define (jolt-throw v) (raise v))
;; Capture the live continuation at the throw site (identity-tagged with the
;; thrown value) so an uncaught error can walk the native frames back to a Clojure
;; 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))
(define (jolt-throw v)
(call/cc (lambda (k) (jolt-throw-cont (cons v k)) (raise v))))
;; ex-info builds the tagged map {:jolt/type :jolt/ex-info :message :data :cause}
;; — a real jolt-hash-map, so the ex-data/ex-message/ex-cause tier fns read it
;; via jolt-get for free. Arity 2 (msg data) or 3 (msg data cause).
@ -408,3 +414,7 @@
;; printing. Loads LAST so its set!-wraps of jolt-class/jolt=2/the printers sit
;; outermost over every earlier extension.
(load "host/chez/java/bigdec.ss")
;; Native stack traces: jv$ns$name -> source registry + continuation frame walk +
;; uncaught-throwable renderer. After the printers/equality it relies on.
(load "host/chez/source-registry.ss")