Fix ResourceWarning from unclosed file handles#1362
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Add __del__ to PDF class to close internally-opened file handles when the object is garbage collected without an explicit close() call. This prevents ResourceWarning in Python 3.11+ when users don't use the context manager pattern. Also fix tests that were not properly closing PDF handles. Closes jsvine#1336
Update __del__ to emit ResourceWarning before closing, matching Python stdlib behavior (io.FileIO, zipfile.ZipFile). This actively nudges users toward context managers rather than silently cleaning up. Also adds docstring to open() promoting the context manager pattern, and updates tests to verify the warning is emitted when close() is forgotten but not when using 'with' or explicit close(). Addresses feedback from jsvine#1336.
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Summary
When
pdfplumber.open()is called with a file path (not a stream), it opens an internal file handle. If the user doesn't use awithstatement or callclose(), that handle leaks until garbage collection, causing aResourceWarningin Python 3.11+.This adds a
__del__method to thePDFclass that closes internally-opened file handles as a safety net. External streams (passed by the caller) are never closed by the destructor, matching the existing behavior inclose().Changes
pdfplumber/pdf.py: Added__del__method that defensively closes internal file handles on garbage collection. Usesgetattr(self, "stream_is_external", True)to safely handle partially-initialized objects.tests/test_resource_warning.py: New test file verifying noResourceWarningis emitted with context manager usage, destructor cleanup, and that external streams are left open.tests/test_mcids.py: Wrappedpdfplumber.open()inwithto fix leaked file handle.tests/test_utils.py: Added missingself.pdf_scotus.close()inteardown_class.CHANGELOG.md: Added entry under Unreleased.README.md: Added to contributors list.Test plan
python -W all -m pytestpasses with noResourceWarningfrom pdfplumbermake lintpasses (black, isort, flake8, mypy --strict)Closes #1336