Return EBADF for negative stat file descriptors by youknowdot · Pull Request #9008 · RustPython/RustPython

youknowdot · 2026-10-08T15:08:26Z

Summary

Extract the negative-descriptor fstat guard from #8954 for the Python 3.14 main branch.

os.stat(-5) and os.fstat(-5) can reach rustix with an invalid ordinary descriptor and panic in debug builds. Return EBADF at the shared non-Windows fstat boundary before calling rustix. Add an interpreter regression covering several negative values, including numbers used as directory-descriptor sentinels elsewhere.

This is a four-line implementation change plus one new Rust integration test. Directory-fd parsing and canonical Python tests are unchanged. It is independent of the closerange/termination fixes in #9006.

Validation

Fresh main-based validation on Linux, with source/runtime identity checked:

Unpatched main panics on the focused probe and the exact new integration test; the split passes both.
Normal commit hooks and strict workspace/C-API Clippy passed.
Workspace tests: 1,353 passed, 18 existing ignored. Separate C-API tests: 116 passed, 4 existing ignored.
Dev and production-feature release builds passed. Both return EBADF for the tested negative descriptors and preserve valid/closed-fd behavior and six existing supported directory-fd cases.
The explicit 22-test canonical selection passed in both builds, with eight unchanged platform/implementation skips. The release test_os fstat selection also passed through cargo run.

The initial broader FileTests run aborts in the separate test_closerange case. The same case aborts on unpatched main; #9006 addresses it. That failed result is retained, and the successful selection excludes that case without changing tests or adding skips. Full local test_os remains unrun because its asyncio setup requires the sandbox-denied AF_UNIX socketpair. Hosted tests remain enabled; cross-platform CI is pending.

The runtime is main's Python 3.14.alpha. Any CPython comparison used the available 3.15.0rc3 interpreter, not a CPython 3.14 build.

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Codex assisted with implementation, extraction, source review, regression tests, and automated validation. The original implementation authorship and Assisted-by trailer are preserved; the regression commit also includes its disclosure.

Return EBADF for negative ordinary descriptors before calling rustix, avoiding debug-build assertions on canonical invalid-fd tests. Keep directory-fd sentinel and absolute-path handling unchanged. Assisted-by: Codex:model-version-unavailable

Exercise ordinary negative descriptors including values accepted by rustix as directory sentinels, without changing canonical tests or directory-fd parsing. Assisted-by: Codex:model-version-unavailable

coderabbitai · 2026-10-08T15:08:34Z

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crates/host_env/src/fileutils.rs
extra_tests/snippets/stdlib_os.py

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youknowone · 2026-10-08T16:43:07Z

do not add python test code in rust file

Preserve the original Unix RustPython-only coverage and every regression assertion while removing the redundant Rust interpreter wrapper. CPython uses -1 as a path sentinel, so keep this regression scoped to its original runtime. Assisted-by: Codex:model-version-unavailable

chatgpt-codex-connector · 2026-10-09T09:27:13Z

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-09T09:31:23.925046Z	`b3052bd`	Draft marked ready

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chatgpt-codex-connector · 2026-10-09T09:31:21Z

+    for stat in (os.stat, os.fstat):
+        for fd in (-1, -5, -9, -100, -(2**31)):


Remove the prohibited test logic

These added loops introduce new test logic and data in extra_tests/snippets/stdlib_os.py, but the root test-code policy says not to modify test assertions, logic, or data and limits acceptable test-file changes to expected-failure decorator updates. Remove this regression-test addition while retaining the Rust fix so the change complies with the repository policy.

AGENTS.md reference: AGENTS.md:L275-L279

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youknowdot added 2 commits October 8, 2026 22:46

Cover negative stat descriptors through the interpreter

30a1e45

Exercise ordinary negative descriptors including values accepted by rustix as directory sentinels, without changing canonical tests or directory-fd parsing. Assisted-by: Codex:model-version-unavailable

youknowone reviewed Oct 8, 2026

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Comment thread tests/negative_fstat.rs Outdated

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do not add python test code in rust file

youknowone approved these changes Oct 9, 2026

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youknowone marked this pull request as ready for review October 9, 2026 09:27

youknowone merged commit 98b2801 into RustPython:main Oct 9, 2026
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Return EBADF for negative stat file descriptors - #9008

Return EBADF for negative stat file descriptors#9008
youknowone merged 3 commits into
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youknowdot:fix-negative-fstat-descriptors

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		for stat in (os.stat, os.fstat):
		for fd in (-1, -5, -9, -100, -(2**31)):

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