[Description:]

As part of the verification for handlers migration from bug 1736924, we've cooked up some ESR 79 profiles with different handlers that we've then migrated to the latest Nightly.
The expectancy is that always ask (excluding irc defaults) are migrated to default save as and all custom settings are preserved.

Please note that the custom handlers.json have been manually constructed (really a headache to add additional file handlers in older versions - makes you apreciate even more Download Panel improvements)

[Steps:]

1. Create new profiles containing the data from:
   1a. windows windows-profile.zip
   1b. mac mac-profile
   1c. ubuntu ubuntu-profile
2. Open the profiles with latest Firefox (Nightly 97)

[Expected Result:]

a. always ask -migrates to save
b. custom actions set, excluding always ask + irc handlers remains as set after migration.
c. default open with firefox remains the same, if not user changed

[Actual Result:]

1a. Windows migration migrated windows-handler.json
mkv, jpe - gets migrated from always ask to use default app.

2a. Mac migration migrated mac-handler.json
mkv - even though is listed as always ask after migration, seems to be wanting to open with default app. although there's none for my mac - also the icon is the one for default app rather than always ask

3a Ubuntu migration migrated ubuntu-handler.json
all good here.

[Notes:]

1. The used handlers.json has been manually edited adding the additional handlers for ESR 78.0.15
2. The used handlers.json contain an intended(after the fact :) ) duplicate

(In reply to Adrian Florinescu [:aflorinescu] from comment #0)

1a. windows windows-profile.zip

in this file, both mkv and jpe are already (ie pre-migration) set to "use default app", because there is no stored ask boolean.

In practice, we would have asked first, because there is no available application (at least, not on my system, pre-96 - but read on for more!). So we would show "always ask" in the preferences, because we cannot display "use [some app]", because we can't figure out what "some app" is supposed to be, and because the downloads code would be in the same situation if you tried to actually download such a file, the preference seems correct and sensible.

However, this changed as a result of bug 1738111, so we now do a better job of finding a default handler and can show the preference as "always open". This changed with 96...

So long story short, this isn't related to the migration. I also don't think it's something we need to fix? The prefs now more correctly reflect the user's intent when configuring, and if they don't, from 96 the prefs will definitely reflect this, so they can adjust the prefs accordingly then. Molly, does that sound right to you? If so, I think we can resolve this invalid / "not a bug"...

I think I agree? I don't see anything here that I would call clearly broken or that we could really improve on.