Fix reproducible builds

[Stypox]

What is it?

• Bugfix (user facing)
• Feature (user facing)
• Codebase improvement (dev facing)
• Meta improvement to the project (dev facing)

Description of the changes in your PR

We want to have reproducible builds on F-Droid so that they can ship our own APK signed with our keys, which would prevent some uninstalling and reinstalling when users switch sources.
All credits for the fix go to @obfusk, also see https://issuetracker.google.com/issues/231837768. It has been confirmed that this works here.

Fixes the following issue(s)

• Closes doesn't build reproducibly (due to bug in coreLibraryDesugaring) #6486

APK testing

The APK can be found by going to the "Checks" tab below the title. On the left pane, click on "CI", scroll down to "artifacts" and click "app" to download the zip file which contains the debug APK of this PR.

Due diligence

• I read the contribution guidelines.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[TobiGr]

Great! I don't have time to check this, but I you guys found a fix, I am more than happy!

[obfusk]

I'm fairly confident the fix works correctly as it simply reuses the relevant AGP code (and I've tested it works).

I can't guarantee it won't break if something changes in AGP though.

And it's a bit ugly since it uses some kotlin functions/variables marked internal (which the JVM doesn't enforce, so I can).

I'm also not that familiar with groovy, so the code could probably be written more idiomatically.

[opusforlife2]

@obfusk Are the Reproducible Builds people aware of this? They might want to take it up with Google.

[Stypox]

He posted the fix in the Google issue tracker: https://issuetracker.google.com/issues/231837768

[obfusk]

@obfusk Are the Reproducible Builds people aware of this?

We are ;p

[opusforlife2]

Nice to see that there is some personnel overlap between the two projects!

[obfusk]

He posted the fix in the Google issue tracker: https://issuetracker.google.com/issues/231837768

I posted my workaround there and told them exactly what & where the problem in the AGP code is.
So it should be trivial to fix now. Hopefully they'll do that soon.

Also: who's "he"? If you meant me, I use "they"(/them) :)

[obfusk]

So it should be trivial to fix now. Hopefully they'll do that soon.

They fixed it.

Not sure when it'll be part of a new AGP release; that'll take a while longer I expect.

[Stypox]

Sorry about the "He", I sometimes forget to use "They" for people I don't know ;-)

[obfusk]

Not sure when it'll be part of a new AGP release; that'll take a while longer I expect.

The .profm fix will be in AGP 8.1.0-alpha03; so I guess we'll probably need the workaround for a while.