From 7c9709802dbe3d4112351785756b77c585567154 Mon Sep 17 00:00:00 2001
From: Bastien Chanot <git@bchanot.fr>
Date: Mon, 6 Jul 2026 19:33:48 +0200
Subject: [PATCH] job4: test memory-commit masked failure (red)
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New T8 in lib/tests/run-deterministic.sh: pre-commit hook that always
rejects (exit 1), then attempts a memory-commit. Demonstrates J4-04
(UNTESTABLE, consequence CRITICAL) against the CURRENT code, on
purpose — this commit is RED: rc=0 (expected 5), stdout leaks the
stale (unchanged) HEAD hash instead of staying empty. `set -uo
pipefail` (no -e) means a rejected `git commit` doesn't stop the
function — it falls through to `git rev-parse --short HEAD`, which
prints the PREVIOUS HEAD and succeeds, so the caller sees what looks
like a valid hash for a commit that never happened. HEAD itself is
correctly unmoved (git did block it) — only the reporting is masked.

This intentionally reds `make test` (memory-commit.sh not yet fixed).
Next commit fixes it.
---
 lib/tests/run-deterministic.sh | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/tests/run-deterministic.sh b/lib/tests/run-deterministic.sh
index 1a5a78a..1d1f9ff 100755
--- a/lib/tests/run-deterministic.sh
+++ b/lib/tests/run-deterministic.sh
@@ -141,6 +141,20 @@ if [ "$after1" -eq "$((base + 1))" ] && [ -n "$h1" ]; then ok "run1 created exac
 if [ "$after2" -eq "$after1" ] && [ -z "$h2" ]; then ok "run2 is a no-op (no 2nd commit, empty stdout)"; else ko "run2 was not a no-op"; fi
 rm -rf "$R"
 
+echo "T8 — pre-commit hook REJECTS commit → fail LOUD (exit 5), no stale hash, HEAD unmoved"
+R="$(new_repo)"
+printf '#!/bin/sh\nexit 1\n' >"$R/.git/hooks/pre-commit"; chmod +x "$R/.git/hooks/pre-commit"
+BEFORE="$(git -C "$R" rev-parse --short HEAD)"
+printf 'REJECTED CHANGE\n' >>"$R/.claude/memory/decisions.md"
+OUT="$( (cd "$R" && "$HELPER" commit "chore(memory): T8 rejected") 2>/dev/null )"
+RC=$?
+AFTER="$(git -C "$R" rev-parse --short HEAD)"
+printf '    rc=%s out=[%s] before=[%s] after=[%s]\n' "$RC" "$OUT" "$BEFORE" "$AFTER"
+if [ "$RC" -eq 5 ]; then ok "rejected commit → exit 5 (fail-loud)"; else ko "expected 5, got $RC (rc0+stale-hash = masked failure)"; fi
+if [ -z "$OUT" ]; then ok "stdout empty on rejection (no stale hash)"; else ko "stdout leaked a hash on rejection: [$OUT]"; fi
+if [ "$BEFORE" = "$AFTER" ]; then ok "HEAD unmoved"; else ko "HEAD moved despite rejection"; fi
+rm -rf "$R"
+
 echo
 printf 'RESULT: %d passed, %d failed\n' "$PASS" "$FAIL"
 [ "$FAIL" -eq 0 ]