FLAC Source does not handle error callback, which may lead to uninitialized `flac_source` and UB

[wro-ableton]

Hey!

We encountered an issue we can reproduce with a specific .flac file. (I'm trying to figure out if I can share it here.)

Basically in flac_source.h, FLAC__stream_decoder_process_until_end_of_metadata triggers the error_callback with FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC and then continues to return true. ni-media interprets this as "OK" as the function (FLAC__stream_decoder_process_until_end_of_metadata) has done what it says it will do.

However, this means, the metadata setup function metadataCallbackImpl is never called and audio::ifstream_info m_info stays uninitialized. Interacting with the stream after this point to my understanding ends in undefined behavior.

To my understanding, implementing the error_callback to throw at the end of the constructor of flac_source should prevent at least this undefined behavior.

Hope this issue can be addressed.
Cheers!

[marcrambo]

Hi, and thanks for reporting. It would be great if you could attach the file.

[wro-ableton]

Sure thing. Zip since .flac is not accepted by GitHub. I forgot to report: We can reproduce this issue on Windows.
Christmas FL Studio Project.zip