fix(export): move EXIF tag parsing out of the finally block - #907
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marcinz606 merged 1 commit intoAug 19, 2026
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`_read_source_meta_exif` silences the tifffile logger, opens the embedded TIFF block in a `try`, and then does all of its parsing inside the `finally`, ending with a `return`. Two consequences. A `return` in `finally` discards any in-flight exception, so Python 3.14 emits `SyntaxWarning: 'return' in a 'finally' block` on every import of this module. And the parsing reads `tif`, which is unbound when `TiffFile()` raises, so a malformed EXIF block surfaced as `UnboundLocalError` instead of the real tifffile error. The outer `except Exception` swallowed either way, so callers still got an empty `_SourceMeta`, but the real cause was unreachable. The `finally` now does only what it exists for, restoring the logger level. The parsing and the `return` sit after it, so a decode failure propagates normally. Behaviour is unchanged: a good EXIF block parses as before, a bad one still returns an empty `_SourceMeta`. Adds `TestSourceMetaExifFallback`, which had no coverage. The SyntaxWarning-free assertion fails against the current source and passes after.
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_read_source_meta_exifsilences the tifffile logger, opens the embedded TIFF block in atry, then does all of its parsing inside thefinallyand returns from there.Two consequences. A
returninfinallydiscards any in-flight exception, so Python 3.14 emitsSyntaxWarning: 'return' in a 'finally' blockon every import of this module. And the parsing readstif, which is unbound whenTiffFile()raises, so a malformed EXIF block came back asUnboundLocalErrorrather than the real tifffile error:The outer
except Exceptioncaught either way, so callers still got an empty_SourceMetaand no behaviour changes here. The real cause was just unreachable.The
finallynow only restores the logger level, and the parsing sits after it.TestSourceMetaExifFallbackis new; this function had no coverage. The SyntaxWarning assertion fails against the current source and passes after; the other three pass both ways.Windows 11, Python 3.14.7, your
[dev]group:4306 passed, 10 skippedontests/with-m "not slow and not metrics". The 2 failures aretest_backend_registry.pyplustek cases needing the optional extra, failing identically without this change.ruff checkandruff format --checkclean.Your CI is
ubuntu-lateston one Python, so the warning would not surface there yet.