ci(integration): fail on a fatal-signal report the exit code can't express

Catch2 arms signal handlers for the duration of each test case, and forked
children of the extension inherit them until they exec. A signal landing in
that window makes the child print a "due to a fatal error condition" block
plus a run summary -- the parent's counters, since it's an address-space copy
-- and die. The parent records nothing and exits 0. Run 29051359074's shm
lane was green with exactly that block in its log.

Scan the captured output and fail the lane when it appears. The underlying
fork window is fixed in Query-farm/vgi (SubProcess et al. now reset signal
dispositions in the child), but this class of failure can never reach the
exit code, so the guard is worth keeping regardless of source.

Use `set +e` around the pipeline rather than `|| true`: the latter runs
before PIPESTATUS is read and overwrites it with true's 0, which would have
silently swallowed every real test failure in the suite.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: rustyconover

ci/run-integration.sh

@@ -257,12 +257,43 @@ rm -f "$STAGE/test/_warm.test"
 # simple_writable); the http lane's writes self-skip.
 echo "Running suite ($SUITE_GLOB, transport=$TRANSPORT) ..."
 suite_rc=0
+
+# run_unittest — invoke haybarn-unittest, streaming its output, and additionally
+# fail on a fatal-signal report that the process's own exit code cannot express.
+#
+# Catch2 arms handlers for SIGTERM/SIGINT/SIGSEGV/... for the duration of a test
+# case. Those handlers are inherited by any process the extension fork()s, and
+# run in the child if a signal lands before it execs. The child then prints a
+# full "FAILED: ... due to a fatal error condition: SIGTERM" block plus a run
+# summary — the *parent's* accumulated counters, since it's an address-space
+# copy — and dies. The parent never sees it, records no failure, and exits 0.
+# The only trace is on stdout, so that is what we scan. Seen on the shm lane in
+# https://github.com/Query-farm/vgi-python/actions/runs/29051359074.
+run_unittest() {
+  local log rc=0
+  log="$(mktemp)"
+  # `set +e` rather than `|| true`: the latter runs before PIPESTATUS is read and
+  # overwrites it with true's 0, silently swallowing every real test failure.
+  set +e
+  "$HAYBARN_UNITTEST" "$@" 2>&1 | tee "$log"
+  rc="${PIPESTATUS[0]}"
+  set -e
+  if grep -q 'due to a fatal error condition' "$log"; then
+    echo "::error::a forked child ran the test harness's signal handler (see the" \
+         "'fatal error condition' block above). The parent exited $rc and would" \
+         "otherwise have passed. This is invisible to the exit code by construction."
+    rc=1
+  fi
+  rm -f "$log"
+  return "$rc"
+}
+
 if [ "$TRANSPORT" = "launch" ]; then
-  "$HAYBARN_UNITTEST" "$SUITE_GLOB" || suite_rc=$?
+  run_unittest "$SUITE_GLOB" || suite_rc=$?
 else
-  "$HAYBARN_UNITTEST" "$SUITE_GLOB" "~test/sql/integration/simple_writable/*" || suite_rc=$?
+  run_unittest "$SUITE_GLOB" "~test/sql/integration/simple_writable/*" || suite_rc=$?
   echo "Running simple_writable (isolated process) ..."
-  "$HAYBARN_UNITTEST" "test/sql/integration/simple_writable/*" || suite_rc=$?
+  run_unittest "test/sql/integration/simple_writable/*" || suite_rc=$?
 fi
 
 exit "$suite_rc"