guess.py:createParser() failure leaves FileInputStream open (Version 3.1.2)

[patricklcam]

Calling guess.py:createParser() with an invalid file type leaves open FileInputSteam object Code is:

     stream = FileInputStream(filename, real_filename, tags=tags)
     return guessParser(stream)

Probably should be something like:

    stream = FileInputStream(filename, real_filename, tags=tags)
    guess = guessParser(stream)
    if not guess:
        stream.close()
    return guess

[vstinner]

Do you want to propose a PR?

[patricklcam]

I don't really have any github experience. Let me investigate how to create a PR and link to this issue. I will get back to you in a day or so.

[patricklcam]

Poked around for a bit and created a PR from a forked branch.

[ticketsvl]

I had a file permission bug on Windows (linux is good) and found guess.py is responsible.

PermissionError: [WinError 32] The process cannot access the file because it is being used by another process:

I didn't find how to close file stream (if guess is valid), so I patched exact same part of code to return stream and close it in my main code. That fixed permission bug for me. return guess, stream

parser_data, parser_stream = createParser(mypath)
metadata = extractMetadata(parser_data)
sec = metadata.get('duration').seconds
width = metadata.get('width')
height = metadata.get('height')
parser_stream.close()

Not sure how to fix this and keep back cap, so @vstinner should to decide. If is there a better way to close stream without patching guess.py return, let me know. Regards.

[vstinner]

Did you see the commit https://github.com/vstinner/hachoir/commit/f536652459c3741da1acf6535517fd69ab9922aa ? It's part of Hachoir version 3.1.3.

[ticketsvl]

Yes, I saw it. And I had an error with this commit and all updates by pip. I could make a new bugreport, but it looks like, it's the same bug as in topic. Commit hadn't fixed it for all cases.

See my code above. Originally it had one return value

parser_data = createParser(mypath)
metadata = extractMetadata(parser_data)

File stream remains open and this code will cause PermissionError in Windows(!) py interpreter, if later code part will try to access same file.

[vstinner]

parser_data = createParser(mypath) metadata = extractMetadata(parser_data)

I don't see guessParser() being called explicitly. Please open a new issue with more details.