[Bug]: "Fix Unlinked Entries" not functioning, only returns None count

[CyanVoxel]

Checklist

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

TagStudio Version

main branch (v9.5.0)

Operating System & Version

macOS 15.1.1

Description

Using the "Fix Unlined Entries" tool only ever returns "None" as the count value, even if there are unlinked entries present in the library.

This seems to stem from this change made to fix_unlinked.py in #528. From what I can tell it seems that set_missing_count() is being passed as a callable function to from_iterable_function and is being called when the done signal inside its CustomRunnable r is emitted - however without any count argument passing to set_missing_count(), resulting in the method's default behavior of setting the count to None.

Expected Behavior

Refreshing the unlinked entries method should return the count of the unlinked entries, and a 0 if none are found. Note that the "None" text currently being shown is not a result of there being no unlinked entries, but rather is an errant None value being displayed as the count.

Steps to Reproduce

1. Open a TagStudio library

2. Move or delete a present in the library on disk to create an "unlinked entry"

3. Go to "Tools -> Fix Unlinked Entries" and click "Refresh All"

4. Note how the count now always says "Unlinked Entries: None"

5. Bonus: Repeat the previous steps while omitting step 2, noting the same result

Logs

No response

[SkeleyM]

id like to work on this