[Bug]: Library Backup is only saved after certain write operations

[Computerdores]

Checklist

• I am using an up-to-date version.
• I have read the documentation.
• I have searched existing issues.

TagStudio Version

Alpha 9.5.6 / latest git

Operating System & Version

--

Description

The library backup created when opening a library of older than expected version¹ is only saved after some write operations have taken place.
One such write operation is the update of the library version², which would mean that restoring from the backup is going to likely fail, since TS will assume that migrations that haven't been applied have already been applied.

Expected Behavior

Any write operations should only happen after a backup has been created, unless the library is already of the current version.

Steps to Reproduce

--

Logs

--

Footnotes

1. see https://github.com/TagStudioDev/TagStudio/blob/main/src/tagstudio/core/library/alchemy/library.py#L535 ↩

2. see https://github.com/TagStudioDev/TagStudio/blob/c4c749650ffd67ce784406935663f893072b6d27/src/tagstudio/core/library/alchemy/library.py#L460 ↩

[Computerdores]

We should also check if older TS versions might modify the library file prior to erroring because it is too old.

And if this is the case we should backport those fixes to avoid possible library corruption for anyone that downloads an older version for whatever reason.