John McCardle
90a2945a9f
Pivots away from atheris (which lacks Python 3.14 support) to a single libFuzzer-linked executable that embeds CPython, registers mcrfpy, and dispatches each iteration to a Python fuzz_one_input(data: bytes) function loaded from tests/fuzz/fuzz_<target>.py by MCRF_FUZZ_TARGET env var. libFuzzer instruments the C++ engine code where all #258-#278 bugs live; Python drives the fuzzing logic via an in-house ByteStream replacement for atheris.FuzzedDataProvider. Python-level exceptions are caught; only ASan/UBSan signal real bugs. CMake - MCRF_FUZZER=ON builds mcrfpy_fuzz from all src/*.cpp except main.cpp plus tests/fuzz/fuzz_common.cpp, linked with -fsanitize=fuzzer,address, undefined. Asset+lib post-build copy added so the embedded interpreter finds its stdlib and default_font/default_texture load. Makefile - fuzz-build builds only mcrfpy_fuzz (fast iterate) - fuzz loops over six targets setting MCRF_FUZZ_TARGET for each - fuzz-long TARGET=x SECONDS=n for deep manual runs - fuzz-repro TARGET=x CRASH=path for crash reproduction - Shared ASAN_OPTIONS / PYTHONHOME env via FUZZ_ENV define tests/fuzz - fuzz_common.cpp: LLVMFuzzerInitialize bootstraps Python, imports target, resolves fuzz_one_input. LLVMFuzzerTestOneInput wraps bytes as PyBytes, calls target, swallows Python errors. - fuzz_common.py: ByteStream byte consumer + safe_reset() + EXPECTED_EXCEPTIONS - Six target stubs (grid_entity, property_types, anim_timer_scene, maps_procgen, fov, pathfinding_behavior) to be fleshed out in follow-up - README with build/run/triage instructions Verified end-to-end: make fuzz-build produces build-fuzz/mcrfpy_fuzz, make fuzz FUZZ_SECONDS=3 ran all six targets (~2400-9800 exec/s each, 667-1883 coverage edges), make fuzz-repro loaded and replayed a corpus input cleanly. No crashes from the stubs. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
23 lines
808 B
Python
23 lines
808 B
Python
"""fuzz_grid_entity - stub. Wave 2 agent W4 will implement.
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Target bugs: #258-#263 (gridstate overflow on entity transfer between
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differently-sized grids), #273 (entity.die during iteration), #274
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(set_grid spatial hash). See /home/john/.claude/plans/abundant-gliding-hummingbird.md.
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Contract: define fuzz_one_input(data: bytes) -> None. The C++ harness
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(tests/fuzz/fuzz_common.cpp) calls this for every libFuzzer iteration.
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Use ByteStream to consume bytes. Wrap work in try/except EXPECTED_EXCEPTIONS.
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"""
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import mcrfpy
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from fuzz_common import ByteStream, EXPECTED_EXCEPTIONS
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def fuzz_one_input(data):
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stream = ByteStream(data)
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try:
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# Minimal smoke: create one grid so the harness verifies end to end.
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mcrfpy.Grid(grid_size=(4, 4))
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except EXPECTED_EXCEPTIONS:
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pass
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