[pyrex41]

Fixes #92

Stacked on #89 (capcov/fix-86-87-home-dir-cache @ 7ad7ae4). The fix doesn't depend on #89: the boot.lua and test changes cherry-pick onto main cleanly. The only conflict is a textual one in CHANGELOG.md, where this entry sits next to #89's. Only the f-modelcheck acceptance run needs #89, because that driver does (cd ...) and then loads relative paths. If #89's branch is merged and deleted, GitHub retargets this PR to main.

Root cause

splice_into_outer (boot.lua, install_fasl) copies a nested load's fasl records into the enclosing recording. The splice exists so that an outer stream has no hole for a nested load. It also ran when the nested load happened inside one of the outer file's chunks: a top-level (load ...) form, or a function that calls load. That load is already in the outer stream as the chunk that calls it. On a warm hit, replaying that chunk ran the nested load again, from its own fasl, and the spliced copy replayed it a second time. Every nested file's output doubled.

Fix

• Skip the splice when the outer span is in_chunk. deps propagation and splicing for loads made outside a chunk are unchanged.
• Bump FASL_FORMAT to SHENFASL7. The fasl key does not cover boot.lua, so caches written by older builds already contain the duplicate. Without the bump, an upgraded build still hit them and printed 36 MC lines. Now they miss once and are rewritten.
• Regression test in test/cli_spec.lua covers two cases: a top-level nested load, and a load from a function. Each is checked cold, warm (asserted to be a fasl hit), warm again, and with SHEN_FASL=off. All runs must print BEGIN LIB LIB END. At 7ad7ae4 the warm checks fail (4 fails); at head they pass.

Evidence (LuaJIT 2.1.1785763465, macOS arm64, private TMPDIR/XDG_CACHE_HOME/SHEN_KERNEL_CACHE/SHEN_FASL_DIR)

Issue repro (--hush-load, cold → warm → warm, then SHEN_FASL=off):

base 7ad7ae4  main.shen   BEGIN|LIB|LIB|END|  BEGIN|LIB|LIB|LIB|LIB|END|  BEGIN|LIB|LIB|LIB|LIB|END|  off: BEGIN|LIB|LIB|END|
head bf3fd90  main.shen   BEGIN|LIB|LIB|END|  BEGIN|LIB|LIB|END|          BEGIN|LIB|LIB|END|          off: BEGIN|LIB|LIB|END|
head bf3fd90  main2.shen  BEGIN|LIB|LIB|END|  BEGIN|LIB|LIB|END|          BEGIN|LIB|LIB|END|          off: BEGIN|LIB|LIB|END|
shen-go 1f587de (load echo filtered)  BEGIN|LIB|LIB|END|  (both files)

capcov f-modelcheck, one fasl dir, run 0 cold then runs 1–3 warm (22 fasl hits, 0 misses):

base 7ad7ae4:  25, 36, 36, 36 MC lines
head bf3fd90:  25, 25, 25, 25 MC lines; payload byte-identical to the shen-go 1f587de reference on every run
head over a fasl dir warmed by base (upgrade path): 25, 25, 25, 25

Suites:

make test  base 7ad7ae4: TOTAL: 1225 pass, 0 fail across 23 specs
make test  head bf3fd90: TOTAL: 1237 pass, 0 fail across 23 specs   (cli_spec 54 -> 66: the new #92 checks)
certify    base 7ad7ae4: passed ... 154  failed ... 0  pass rate ... 100%
certify    head bf3fd90: passed ... 154  failed ... 0  pass rate ... 100%

🤖 Generated with Claude Code