git - JGit: Checkout a remote branch

Question

I'm using JGit to checkout a remote tracking branch.

Git binrepository = cloneCmd.call()

CheckoutCommand checkoutCmd = binrepository.checkout();
checkoutCmd.setName( "origin/" + branchName);
checkoutCmd.setUpstreamMode(CreateBranchCommand.SetupUpstreamMode.TRACK );
checkoutCmd.setStartPoint( "origin/" + branchName );

Ref ref = checkoutCmd.call();

The files are checked out, but the HEAD is not pointing to the branch. Following is the git status output,

$ git status
# Not currently on any branch.
nothing to commit (working directory clean)

The same operation can be performed in git command line, easily and it works,

git checkout -t origin/mybranch

How to do this JGit?

Answer 1

You have to use setCreateBranch to create a branch:

Ref ref = git.checkout().
        setCreateBranch(true).
        setName("branchName").
        setUpstreamMode(CreateBranchCommand.SetupUpstreamMode.TRACK).
        setStartPoint("origin/" + branchName).
        call();

Your first command was the equivalent of git checkout origin/mybranch.

(Edit: I submitted a patch to JGit to improve the documentation of CheckoutCommand: https://git.eclipse.org/r/8259)