Support unused import removal with Buildifier

[psimmons-vistar]

It would be nice if Buildifier could support detecting and removing unused load statement imports.

Would definitely be willing to work on this if I could be given some guidance on if this makes conceptual sense in Buildifier, and where in the code a modification like this would happen.

[laurentlb]

Agree. This is blocked on this Bazel change: bazelbuild/bazel#5636
After that, it will be safe to remove those.

[kastiglione]

According to https://github.com/bazelbuild/buildtools/blob/master/buildozer/README.md, buildozer has a fix unusedLoads command.

[psimmons-vistar]

Sweet, I was wondering if it would've made more sense in buildozer. Thanks

[mboes]

But AFAIK, buildozer only works on BUILD files, not Starlark files, right? How do I detect and remove unused imports in Starlark files?

[vladmos]

You can use buildifier:

$ buildifier --lint=fix --warnings=load your/file.bzl

[thundergolfer]

@vladmos That command didn't do anything for me (version 0.29.0). This works though:

buildozer 'fix unusedLoads' //...:* (at least on BUILD files)

[vladmos]

That's weird, could you please share a file that's not being fixed with buildifier?