init in compile mode is ~2.4 s (tier loading, analyzer self-compile, macro
recompilation), paid by every process that builds a ctx from source — each
jpm-test file, embedders, workers. init-cached marshals the built ctx to a
disk image (same root-env dicts as snapshot/fork) and later processes
unmarshal it in ~5 ms, any process: nothing from the baking process is
needed at load.
The cache key fingerprints the embedded .clj stdlib (which covers jolt-core:
analyzer, IR, core tiers), the .janet seed sources next to the module, the
janet version, the init opts, and the env knobs that shape a ctx (JOLT_PATH/
MUTABLE/AOT_CORE/FEATURES) — any change rebuilds. Corrupt or non-ctx images
fall back to a rebuild (unmarshal of garbage can 'succeed' with a scalar, so
the shape is checked, not just the throw). Writes are atomic (tmp + rename)
so racing cold starts never publish a torn image. JOLT_NO_IMAGE_CACHE=1
opts out; JOLT_IMAGE_CACHE_DIR overrides the location (default TMPDIR).
Test consumers switch to init-cached (harness, suite-worker, conformance,
the behavioral unit/integration tests); tests that validate the bootstrap
itself (bootstrap-fixpoint, staged-bootstrap, aot round-trip, direct-linking)
and the deps tests (tmp-dir :paths would fragment the key) keep real init.
Full jpm test: 2:46 -> 1:58 (~29%). New ctx-image-test covers cold/warm,
cross-process load (subprocess runs defn/redef/macros/protocols/multimethods
off the baked image), per-opts keying, and corrupt-image fallback.
compile-and-eval wrapped the compile step in a blanket protect — any failure,
including a genuine compiler bug, silently fell back to the interpreter and
hid behind a correct-looking result. Now only the analyzer's deliberate punt
signal (jolt/uncompilable: …) falls back; any other compile-step error
propagates.
Tightening this surfaced one accidental dependency: pre-kernel overlay forms
(00-syntax's destructure defn) trigger a compile while ensure-analyzer is
still gated, and the missing analyzer crashed var-get with a cryptic indexing
error that the blanket catch happened to convert into the designed interpret
fallback. That path now punts explicitly ("jolt/uncompilable: analyzer not
built (pre-kernel bootstrap)").
New unit test stubs jolt.analyzer/analyze to prove a non-punt error
propagates while the punt channel still falls back.
Gate: conformance 269x3, fallback-zero, fixpoint stage1==2==3, self-host,
sci-bootstrap, staged-bootstrap, all specs+unit, suite 4046>=4034 (5 timeouts);
core-bench A/B neutral (4562 vs 4572 ms).
