Fix checking voice files in custom data dirs

[ichthyosaurus]

This fixes piper re-downloading already downloaded models with the --data-dir option. It now checks for every model if it exists in one of the data dirs. It only downloads models if they are actually missing, or if all existing files were invalid.

Without this fix, piper schedules a model file for download if it is missing in any data directory. As "." is always in the list of data dirs, models are re-downloaded if they don't exist in the current working dir. With this fix, it only downloads files that are missing in all data dirs.

[MullPointer]

I had observed the same behaviour and from a read through this pull request looks like it should fix it. Thanks for saving me from having to explain it, @ichthyosaurus.

However, I am not sure that it is a good idea to delete models with incorrect sizes or hashes without user confirmation in case they were custom models or the sizes or hashes listed are wrong. Suggest piper should just put up the warning and continue to check other data dirs.

[ichthyosaurus]

However, I am not sure that it is a good idea to delete models with incorrect sizes or hashes without user confirmation in case they were custom models or the sizes or hashes listed are wrong. Suggest piper should just put up the warning and continue to check other data dirs.

Thanks, that makes sense. I updated the PR.

[xandark]

I've run into this exact issue as a new user of piper, which I love regardless of the issue. Seeing as there are no conflicts, is there a reason why this cannot be merged?