Git local repo doesn't show the name of the branch

Question

I have a Jenkins Maven build where the git client issues the following commands:

git rev-parse --is-inside-work-tree
git config remote.origin.url ssh://git@HOST:PORT/Project/main.git
git --version
git fetch --tags --progress ssh://git@HOST:PORT/Project/main.git +refs/heads/*:refs/remotes/origin/*
git rev-parse refs/remotes/origin/BRANCH_1^{commit}
git rev-parse refs/remotes/origin/origin/BRANCH_1^{commit}
git config core.sparsecheckout
git checkout -f f60bbb84ae0189b766a357a7d589b14c360f9c03
git rev-list 0caaf02f6a5789e54c6562f4d34632eb8e0a7e89

and checks out the requested BRANCH_1 branch. In its workspace, the Git configuration file contains only the following rows:

[core]
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = true
[remote "origin"]
    url = ssh://HOST:PORT/Project/main.git
    fetch = +refs/heads/*:refs/remotes/origin/*
    prune = true

In these circumstances, JGit lists only

HEAD for

repository.eaxctRef(Constants.HEAD).getLeaf().getName()

and origin for

git.remoteList().call().get(i).getName()

How could I retrieve, using JGit, the branch name, in this case, BRANCH_1 ?

The used JGit version is 4.9.0.201710071750-r.

Answer 1

The command git checkout -f puts your repository into a state called detached head . Hence the result of JGit's exactRef() is correct.

In order to find branches that point to the commit that you checked out, JGit provides an implementation of git name-rev --refs=refs/heads/* <commit id> .

For example:

git.nameRev().add( ObjectId.fromString( "abc123..." ).addPrefix( "refs/heads" ).call();

will return a map of commit ids to names. Note, however, that if multiple branches point to the given commit, JGit will return an arbitrary matching branch name.