branch: introduce --show-current display option

When called with --show-current, git branch will print the current
branch name and terminate. Only the actual name gets printed,
without refs/heads. In detached HEAD state, nothing is output.

Intended both for scripting and interactive/informative use.
Unlike git branch --list, no filtering is needed to just get the
branch name.

Signed-off-by: Daniels Umanovskis <daniels@umanovskis.se>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
index ee6787614c..be55148930 100755
--- a/t/t3203-branch-output.sh
+++ b/t/t3203-branch-output.sh
@@ -100,6 +100,50 @@ test_expect_success 'git branch -v pattern does not show branch summaries' '
 	test_must_fail git branch -v branch*
 '
 
+test_expect_success 'git branch `--show-current` shows current branch' '
+	cat >expect <<-\EOF &&
+	branch-two
+	EOF
+	git checkout branch-two &&
+	git branch --show-current >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git branch `--show-current` is silent when detached HEAD' '
+	git checkout HEAD^0 &&
+	git branch --show-current >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_success 'git branch `--show-current` works properly when tag exists' '
+	cat >expect <<-\EOF &&
+	branch-and-tag-name
+	EOF
+	test_when_finished "
+		git checkout branch-one
+		git branch -D branch-and-tag-name
+	" &&
+	git checkout -b branch-and-tag-name &&
+	test_when_finished "git tag -d branch-and-tag-name" &&
+	git tag branch-and-tag-name &&
+	git branch --show-current >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git branch `--show-current` works properly with worktrees' '
+	cat >expect <<-\EOF &&
+	branch-one
+	branch-two
+	EOF
+	git checkout branch-one &&
+	git worktree add worktree branch-two &&
+	{
+		git branch --show-current &&
+		git -C worktree branch --show-current
+	} >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'git branch shows detached HEAD properly' '
 	cat >expect <<EOF &&
 * (HEAD detached at $(git rev-parse --short HEAD^0))