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Sean WhalenandClaude Opus 5
d185bd0526
parse_report_file's path branch opened the file with open(file_path, "rb") and then, on a later line, called file_object.read() followed by file_object.close() with no exception handling between them. An exception from read() (e.g. an OSError from the underlying storage) skipped close() and left the descriptor to be released only when Python's garbage collector eventually finalized the object, rather than closed deterministically (CPython's io.IOBase.__del__ closes an unclosed file on finalization: https://docs.python.org/3/library/io.html). This is the pattern CodeQL's py/file-not-closed query flags, found in a local code-quality scan. The path branch now opens the file with a `with` block, so the handle is closed on both the success and exception paths. The fix is scoped to only that branch: a BytesIO created internally from bytes/bytearray/memoryview input, and a file-like object supplied by the caller, are both closed only after a successful read and left open if read() raises, exactly as before this commit. Widening that to close a caller-supplied handle on the exception path too would be a behavior change outside this fix's scope. Also closes tests/test_init.py's TestGetDmarcReportsFromMailboxMaildir ._deliver, which did open(source, "rb").read() with no close() at all; it now uses a `with` block. Two regression tests cover the narrowed contract: - testParseReportFileClosesHandleOnReadError patches builtins.open (the SDK boundary) with a fake handle implementing the context-manager protocol, and asserts close() is called when read() raises. Verified against origin/master's version of parsedmarc/__init__.py: the test fails with "AssertionError: False is not true" (close was never called), confirming it catches the leak. - testParseReportFileLeavesCallerHandleOpenOnReadError passes a caller-supplied fake handle directly as input_ and asserts close() is NOT called when read() raises. Verified against a naive whole-block try/finally (wrapping close() around all three branches instead of only the path branch): the test fails with "AssertionError: True is not false" (close was called), confirming it catches the scope widening this PR must avoid. Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>