Author rmccampbell7
Recipients rmccampbell7
Date 2018-12-12.19:06:57
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Marked as misclassified Yes
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The mimetypes.guess_all_extensions function is defined as:

def guess_all_extensions(self, type, strict=True):
    type = type.lower()
    extensions = self.types_map_inv[True].get(type, [])
    if not strict:
        for ext in self.types_map_inv[False].get(type, []):
            if ext not in extensions:
    return extensions

If any mime type exists in both the strict and non-strict types_map_inv and it is called with strict=False, then it will modify the strict list in-place which effects future calls even with strict=True. While this doesn't manifest as an error for me because the dictionaries are non-overlapping, it is a potential error; it is also vulnerable to people accidentally modifying the returned list. The list should be copied after the first lookup.
Date User Action Args
2018-12-12 19:06:57rmccampbell7setrecipients: + rmccampbell7
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2018-12-12 19:06:57rmccampbell7linkissue35474 messages
2018-12-12 19:06:57rmccampbell7create