[Bug]: BIT7Z_AUTO_FORMAT is fail

[psvajaz]

[Bug]: BIT7Z_AUTO_FORMAT is fail

[rikyoz]

Hi!
Thanks for reporting the bug!

After reading the source code, it was found that the file suffix name should be determined first. If the determination is successful, detectFormatFromSig will not be run for file configuration determination, which may cause compressed files to not open properly

I replicated your usage scenario, and indeed bit7z fails to detect the format.
However, the problem is not that detectFormatFromSig is not called.

The BitInputArchive::openArchiveStream method takes into account precisely the case where a format was detected from the extension, but we could not open the archive:

HRESULT res = in_archive->Open( in_stream, nullptr, open_callback );

if ( res != S_OK && mArchiveHandler.format() == BitFormat::Auto && !detected_by_signature ) {
    /* ... */
    mDetectedFormat = &( detectFormatFromSig( in_stream ) );
    ...
}

The actual problem is that, in some cases, the call to Open might change the state of the underlying file stream so that when detectFormatFromSig tries to read the file signature, it fails, hence the format detection error.
I've pushed a commit to the develop branch that fixes this issue.

Thank you again! 🙏

[rikyoz]

Fixed in v4.0.0.