Only filter ignored paths from module specifier generation if there exists a better option

[andrewbranch]

Fixes #42785
Fixes #43011

Sometimes the resolver can’t come up with a module specifier that doesn’t have an “ignored path” (like .pnpm or .prisma) in it. In those cases, we need to use the undesirable ignored path. In @dlannoye’s repro, the .pnpm path never actually manifests in a declaration file—the resolver separately finds an accessible re-export and uses that, but there was nevertheless an assertion that we could come up with something for the declaring module itself. The test case included is based off of @flybayer’s repro. This case does result in a type serialization that references node_modules/.prisma directly, which isn’t great, but that would have happened in 4.1 and earlier as well. (The real example from @flybayer has noEmit enabled, so in fact neither real-world case actually exhibits bad behavior with this PR. And I think for the Prisma case, it’s not strictly harmful if declaration files reference ".prisma" anyway, since that folder will have to get created during build/install for "@prisma/client" to work.)

[weswigham]

Is the assertion that triggered the crash still correct to have? Is this function no longer able to return undefined in the cases that feed into that assertion?

[DanielRosenwasser]

Does this fix #43011 too? Looks potentially similar, mentions .pnpm.

[andrewbranch]

Yes. Fixes #43011.

[andrewbranch]

Is the assertion that triggered the crash still correct to have? Is this function no longer able to return undefined in the cases that feed into that assertion?

Yeah, the assertion is correct, and the function I changed is now once again guaranteed to call its callback at least once. (If we skip the filtering, targets always contains at least importedFileName and will run on that, unless better symlinks are found.)

[andrewbranch]

@typescript-bot cherry-pick this to release-4.2

[typescript-bot]

Heya @andrewbranch, I've started to run the task to cherry-pick this into release-4.2 on this PR at a687bae. You can monitor the build here.

[andrewbranch]

@typescript-bot cherry-pick this to release-4.2

[typescript-bot]

Heya @andrewbranch, I've started to run the task to cherry-pick this into release-4.2 on this PR at 7597f52. You can monitor the build here.

[typescript-bot]

Hey @andrewbranch, I've opened #43032 for you.