[Bug] Updates screen is flooded after migration

Device information

• Tachiyomi version: r3185

Steps to reproduce

1. Clear database in advanced settings to make sure you don’t have prefetched chapters from different source.
2. Open a manga in your library.
3. ⋮ -> Migrate -> Choose manga from different source -> Migrate.
4. Go to the Updates screen.

Expected behavior

See new chapters from different manga and sources.

Actual behavior

See too many chapters from the manga you just migrated.

Other details

PR that caused the issue to be more annoying #4645. Before this, chapters where also filtered by upload date, so chapters older than 3 months didn’t show up in the Updates. So even when manga is released weekly, it would show about 12 chapters, but now it will show all chapters from the manga. And if you migrate a manga with more than 500 chapters, the Updates screen becomes entirely useless since number of chapters there is limited to 500.

I also tried to fix it myself in the migration code (wanted to transfer fetch date along with read status), but I couldn’t, that’s why I’m creating this issue.

[arkon]

Yes, we could potentially coalesce it in the query, or set it when creating the chapter objects.

[stevenyomi]

Also if you add a title without fetching its chapters (either by long pressing it from the manga list or in the details screen but your connection is too slow) and visit it afterwards, all its chapters will show up in Updates screen. You have to manually remove and readd the title to clear them out.