branch: fix branch renaming not updating HEADs correctly

diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 9f353c0efce82e4492b0f3ce3acce1756827462e..c5c371888bdef6caa8336eb99e935126674b5e76 100755 (executable)
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -145,6 +145,19 @@ test_expect_success 'git branch -M baz bam should add entries to .git/logs/HEAD'
        grep "^0\{40\}.*$msg$" .git/logs/HEAD
 '
 
+test_expect_success 'git branch -M should leave orphaned HEAD alone' '
+       git init orphan &&
+       (
+               cd orphan &&
+               test_commit initial &&
+               git checkout --orphan lonely &&
+               grep lonely .git/HEAD &&
+               test_path_is_missing .git/refs/head/lonely &&
+               git branch -M master mistress &&
+               grep lonely .git/HEAD
+       )
+'
+
 test_expect_success 'git branch -M baz bam should succeed when baz is checked out as linked working tree' '
        git checkout master &&
        git worktree add -b baz bazdir &&