Run Gazelle in dry-run or warn mode

Context

Is there a way to have gazelle run in dry-run mode?

I'd like to create a CI job that runs gazelle with dry-run and fails if gazelle finds any changes.

Something like this

$ bazel run //:gazelle --dry-run || exit 1

Different Approach

I think this can be accomplished by running the command and seeing if git finds any changes, but I would prefer a non-git approach.

The -mode diff flag should work perfectly here when running in update mode (the default):

https://github.com/bazelbuild/bazel-gazelle#fix-and-update

$ bazel run //:gazelle -- -mode diff || exit 1

I'm working on making a bazel test that would enforce this, will share if/when I get something working!