How do I get the git revision of my project assuming there are no committed changes?

Question

I want a way to be able to return "unknown" as my git revision if I have uncommitted changes locally. If not, it should return the correct git revision.

String getGitRevision() {
    String gitRevision = "unknown"
    try {
        def cmd = "git rev-parse HEAD"
        def proc = cmd.execute()
        gitRevision = proc.text.trim()
    }
    catch (IOException ioe) {
        println "Fetch revision failed."
    }
    return gitRevision;
}

I expect that when I have uncommitted changes locally, getGitRevision() returns unknown.

But even when I have uncommitted changes, it grabs the correct revision id. I'm not really sure how to add that logic in.

Answer 1

HEAD is parseable as a commit as long as there is a current commit, and there is almost always a current commit. "Uncommitted changes" is not relevant to whether there is a current commit.

To compare the index and work-tree to the current commit, use git status . To do this reliably, in your own software, consider using git --no-optional-locks status --porcelain=v2 , perhaps with -z as well, and reading its output, which is shown in the git status documentation . Your code can then choose what to consider "uncommitted changes" (including untracked files, and, if you add --ignored , ignored files).

For this particular case, you can just use git describe --always --dirty and check for the -dirty suffix. Or—since this is what git describe itself does—run git diff-index --quiet HEAD and check its exit status: 0 means "not dirty", 1 means "dirty", anything else means "unable to tell, something went wrong". The method using git status --porcelain... is the most flexible, as it lets you define what you mean by "dirty", but the other two are much simpler.