changefinder

changefinder will compare the current branch to the origin/master branch then determine which submodules, excluding internal submodules, had changes, and list them on stdout. The default is emit them in a simple newline delimited list.

The available flags are as follows:

• -dir=[absolute path]: The directory to diff, defaults to current working directory.
• -q: Enables quiet mode with no logging. In the event of an error while in quiet mode, all logs that were surpressed are dumped with the error. Defaults to false (i.e. “verbose”).
• -format=[plain|github|commit]: The stdout output format. Default is plain.
• -gh-var=[variable name]: The variabe name to set output for in github format mode. Defaults to submodules.
• -base=[ref name]: The base ref to compare HEAD to. Default is origin/main.
• -path-filter=[path filter]: The path filter to diff for.
• -content-pattern=[regex]: A regex to match on diff contents.
• -commit-message=[commit message]: Message to use in the nested commit block
• -commit-scope=[conventional commit scope]: Scope to use for the commit e.g. fix
• -touch: touches the CHANGES.md file to elicit a submodule change - only works when used with -format=commit

Example usages from this repo root:

# targeting a git repository other than current working directory
go run ./internal/actions/cmd/changefinder -dir /path/to/your/go/repo

# quiet mode, github format
go run ./internal/actions/cmd/changefinder -q -format=github

# quiet mode, github format, github var name "foo"
go run ./internal/actions/cmd/changefinder -q -format=github -gh-var=foo

How to bump all changed modules for release using -touch

The -touch flag is best used when attempting to generate nested commits for an already submitted change. For example, a GAPIC generator change touches every gapic module, but the PR doesn't have nested commits for each changed module. The PR is submitted as is, perhaps because it was included with a bunch of other changes or for timing purposes, and the nested commits were not added with changefinder while the PR was open. In this case, we can do the following using changefinder:

1. checkout the merged commit with the target changes: git checkout <some commit has>
2. “save” this to a branch: git checkout -b changed
3. checkout the commit just before the target commit: git checkout <the commit just before>
4. “save” this to a branch : git checkout -b base
5. checkout the changes: git checkout changed
6. generate the nested commits to stdout, and add a temporary blank line to each module. release-please should clean up the blank lines later.

go run ./internal/actions/cmd/changefinder -q \
  -format=commit \
  -base=base \
  -commit-scope=fix \
  -commit-message="describe the change" \
  -touch

7. checkout main, new branch, commit:

git checkout main && \
  git checkout -b bump-modules && \
  git commit -a -m 'chore: bump changed modules' && \
  git push

8. create a PR in GitHub from your branch.
9. copy/paste the nested commit messages from stdout to the description of your GitHub PR.