[CP] Fixes multiple fixes for insertions in multi-file library

[FMorschel]

Commit(s) to merge

https://dart-review.googlesource.com/c/sdk/+/401865

Target

Stable

Prepared changelist for beta/stable

https://dart-review.googlesource.com/c/sdk/+/403380

Issue Description

All platforms are affected.

The dart fix command applies insertions for all files in the library after #55520. This means that in a library with two files if we have errors on both and one of them has an insertion fix (say adding const ), that insertion is added twice.

The desired behaviour is to only do so for the current file since it runs for every file anyway. The initial issue was about detecting the fixes needed for part files but it didn't consider only fixing for a single file at a time, as it was doing previously.

What is the fix

The fix removes the loop for all units in the library and only runs for the unit with the current path.

Why cherry-pick

It creates errors in code fixes.

Risk

The risk of merging is low.

Issue link(s)

#59572

Extra Info

CC @pq

[dart-github-bot]

Summary: dart fix incorrectly applied insertions multiple times in multi-file libraries. The fix restricts insertions to the current file, resolving duplicate additions.

[FMorschel]

I'm unsure if I should create yet another CP for beta in this case (my first CP). Thanks for your time!

[athomas]

@bwilkerson WDYT?

[bwilkerson]

@FMorschel The prepared changelist for beta/stable (https://dart-review.googlesource.com/c/sdk/+/403380) does not appear to have the actual bug fix in it. (The path isn't being passed in and used.)

@athomas Once the CL is correct, I think the change has significant value to developers working in libraries that have parts (though I don't know how many developers fall into that category) and very low risk. Most of the changes are in test code; the meaningful changes amount to three lines of code.

[FMorschel]

Thanks @bwilkerson! Fixed that and rebased it.

[FMorschel]

I'll do it for beta later then if you want me to. Thanks!