jolt/test/conformance

Conformance: certifying the corpus against reference Clojure

See SPEC.md for the full host-neutral language-spec contract: the corpus schema, conformance levels, the feature profile, and how to host jolt on a new runtime. This README covers the certification tooling specifically.

The corpus (test/chez/corpus.edn) is jolt's host-neutral behavioral suite — one row per case: {:suite :label :expected :actual}, where :actual is a Clojure source expression and :expected its result (or :throws). The runtime harness (host/chez/run-corpus.ss, invoked by make corpus) replays it on Chez and compares by value-equality.

Every :expected is sourced from reference JVM Clojure, so the corpus is both a regression suite and a specification certified against Clojure rather than against its authors' beliefs. This directory holds the certification tooling that closes that gap.

What's here

• certify.clj — runs every corpus row's :actual and :expected through reference JVM Clojure (each in a fresh user namespace, output/stdin sunk, a 5s per-case watchdog) and compares with Clojure's =. It buckets each row:

  • certified / certified-throws — jolt's :expected matches real Clojure
  • divergent — both evaluate but jolt's :expected disagrees with Clojure
  • throws-mismatch — jolt and Clojure disagree on whether it throws
  • jvm-error — :actual isn't runnable on vanilla Clojure (host-coupled / jolt-specific) — informational, not certifiable
  • read-error / timeout — won't read on the JVM reader, or ran too long

• known-divergences.edn — every current divergence, classified. Most are deliberate jolt-specific or host-model deltas (see :legend): the all-double numeric model, snapshot-heap concurrency, the no-JVM host model, jolt reader features, the jolt printer, intentional strictness. A few are genuine :bug entries with a tracked bead. These categories become the :features flags in conformance inc3.

make certify is the gate wrapper. It skips cleanly when clojure (JVM) is not installed; otherwise it runs certify.clj and fails the build on a NEW (unclassified) divergence or a stale allowlist entry. Flaky entries (JVM result is timing-dependent, e.g. future-cancel) are tolerated either way.

Running

make certify                                                 # the gate wrapper (skips if clojure absent)
clojure -M test/conformance/certify.clj                      # gate directly (exit≠0 on new/stale)
clojure -M test/conformance/certify.clj test/chez/corpus.edn --edn /tmp/report.edn  # full machine-readable report

Current state

Of ~2740 vanilla-certifiable rows, >2730 match reference Clojure exactly; the handful of divergences are all classified (deliberate deltas plus a few tracked bugs). The corpus is trustworthy as a spec, with the host-specific deltas made explicit rather than hidden.

Adding / changing cases

When you add corpus rows or change behavior, re-run the certifier. A NEW divergence means either a real bug (file it, tag the allowlist entry :bug + :bead) or a deliberate delta (classify it). A stale entry means a divergence was fixed — remove it from known-divergences.edn.