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Phase 5.B c22b-mech amend-3: fix (3-gate) per testkeeper 16:03:00Z FAIL.
Two root causes diagnosed by testkeeper: - (A) script bug: EXTRA_CXXFLAGS env var not consumed by build_phoenix.sh (it expects EXTRA_CMAKE_FLAGS); -DJIT_TEST_VARIADIC_BRIDGE never reached the cmake compile flags -> shadow-emit divergence path was compiled out - (B) test-fixture inadequacy: fib(10) uses small interned ints whose refcount never decreases to zero, so MakeDecref dealloc-fallthrough generates site 600 in compiled code but never executes it at runtime. (Pythia python#376 second-order risk lands empirically.) Fix: - (A) EXTRA_CXXFLAGS -> EXTRA_CMAKE_FLAGS=" -DJIT_TEST_VARIADIC_BRIDGE=1 -DJIT_TEST_EXERCISE=1" (also forces counter into release build for diagnostic disambiguation) - (B) Replace fib(10) with stress fixture: 1000 iters of [None]*100 list alloc + dealloc; lists are not interned, deallocs reach _Py_Dealloc Diagnostic added: counter delta surfaced inline. If counter == 0 even with EXERCISE flag, FAIL-DIAGNOSTIC explicit (site re-selection for c23+). Disambiguates (3-gate) FAIL between mechanism bug and traversal inference failure. Self-attribution: third amendment cycle on c22b-mech demonstrates the recursive split from c22 -> c22a + c22b-api + c22b-mech accretes verification debt. Pythia python#380 escape-hatch concern compounds — this fix restores (3-gate) falsifiability but the FAIL surfaced only because testkeeper invoked the opt-in env-var. Without explicit invocation the mechanism degraded silently (script bug on first execution).
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‎scripts/gate_phoenix.sh‎

Lines changed: 35 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -162,29 +162,50 @@ else
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fi
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# (3-gate) JIT_TEST_VARIADIC_BRIDGE deliberate-divergence build probe.
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# A fully-instrumented gate would: rebuild JIT with -DJIT_TEST_VARIADIC_BRIDGE,
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# run force_compile fib expecting non-zero exit + grep "shadow-emit: input
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# count mismatch" in stderr. Re-building costs ~5min; we INFO-out unless
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# the env var JIT_VARIADIC_BAD_PATH_VERIFY=1 is set.
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# A fully-instrumented gate would: rebuild JIT with -DJIT_TEST_VARIADIC_BRIDGE
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# (via EXTRA_CMAKE_FLAGS — build_phoenix.sh propagates to CMAKE_CXX_FLAGS),
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# also -DJIT_TEST_EXERCISE so we can verify the wrapper IS reached, then run
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# a stress fixture that forces JIT-compiled code through _Py_Dealloc on
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# non-interned objects (small-int interning means fib(10) doesn't trigger
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# site 600 at runtime; lists/tuples of large objects do). Expected: counter
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# > 0 AND JIT_CHECK fires with "shadow-emit: input count mismatch".
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# Re-building costs ~5min; INFO-out unless JIT_VARIADIC_BAD_PATH_VERIFY=1.
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if [ "${JIT_VARIADIC_BAD_PATH_VERIFY:-0}" = "1" ]; then
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echo "(3-gate) JIT_VARIADIC_BAD_PATH_VERIFY=1 — rebuilding with -DJIT_TEST_VARIADIC_BRIDGE..." | tee -a "$RESULTS_FILE"
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echo "(3-gate) JIT_VARIADIC_BAD_PATH_VERIFY=1 — rebuilding with -DJIT_TEST_VARIADIC_BRIDGE -DJIT_TEST_EXERCISE..." | tee -a "$RESULTS_FILE"
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BAD_PATH_LOG=/tmp/jit_variadic_bad_path_$$.log
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pushd "$CPYTHON_ROOT" >/dev/null
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EXTRA_CXXFLAGS="-DJIT_TEST_VARIADIC_BRIDGE=1" bash scripts/build_phoenix.sh --pydebug --clean > "$BAD_PATH_LOG" 2>&1
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EXTRA_CMAKE_FLAGS=" -DJIT_TEST_VARIADIC_BRIDGE=1 -DJIT_TEST_EXERCISE=1" \
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bash scripts/build_phoenix.sh --pydebug --clean > "$BAD_PATH_LOG" 2>&1
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BAD_BUILD_RC=$?
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popd >/dev/null
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if [ "$BAD_BUILD_RC" -eq 0 ]; then
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BAD_RUN=$("$PYTHON" -c "import _cinderx, cinderjit
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def fib(n):
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a, b = 0, 1
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for _ in range(n): a, b = b, a + b
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return a
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cinderjit.force_compile(fib); fib(10)" 2>&1 || true)
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BAD_RUN=$("$PYTHON" -c "
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import _cinderx, cinderjit, ctypes
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# Stress fixture: non-interned object decref reliably reaches _Py_Dealloc
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# (site 600). fib(10) only uses interned small ints which never decref to
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# zero; need actual deallocs.
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def stress():
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for _ in range(1000):
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x = [None] * 100 # list dealloc each iter; non-interned
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return 1
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cinderjit.force_compile(stress)
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try:
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libpy = ctypes.CDLL(None)
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cnt = ctypes.c_int.in_dll(libpy, 'g_lir_bbb_append_invoke_call_count')
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pre = cnt.value
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except (AttributeError, ValueError):
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pre = -1
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stress()
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if pre >= 0:
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print(f'JIT_TEST_EXERCISE counter delta: {cnt.value - pre}')
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" 2>&1 || true)
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echo "$BAD_RUN" | tee -a "$RESULTS_FILE"
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if echo "$BAD_RUN" | grep -q "shadow-emit"; then
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echo "(3-gate) PASS: JIT_CHECK fired with shadow-emit message (negative-test gate-verified)" | tee -a "$RESULTS_FILE"
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elif echo "$BAD_RUN" | grep -qE "JIT_TEST_EXERCISE counter delta: 0$"; then
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echo "(3-gate) FAIL-DIAGNOSTIC: counter == 0 — stress fixture did not reach site 600. site re-selection required for c23+ (theologian fib-traversal inference falsified)" | tee -a "$RESULTS_FILE"
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else
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echo "(3-gate) FAIL: bad-path build did not fire JIT_CHECK on force_compile fib" | tee -a "$RESULTS_FILE"
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echo "$BAD_RUN" | tail -10 | tee -a "$RESULTS_FILE"
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echo "(3-gate) FAIL: bad-path build did not fire JIT_CHECK on stress fixture" | tee -a "$RESULTS_FILE"
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fi
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else
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echo "(3-gate) INFO: bad-path build failed (log $BAD_PATH_LOG)" | tee -a "$RESULTS_FILE"

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