Merge branch 'rj/branch-copy-and-rename' into maint-2.39

Fix a pair of bugs in 'git branch'.

* rj/branch-copy-and-rename:
  branch: force-copy a branch to itself via @{-1} is a no-op

Author: gitster

builtin/branch.c

@@ -581,13 +581,13 @@ static void copy_or_rename_branch(const char *oldname, const char *newname, int
 	strbuf_release(&logmsg);
 
 	strbuf_addf(&oldsection, "branch.%s", interpreted_oldname);
-	strbuf_release(&oldref);
 	strbuf_addf(&newsection, "branch.%s", interpreted_newname);
-	strbuf_release(&newref);
 	if (!copy && git_config_rename_section(oldsection.buf, newsection.buf) < 0)
 		die(_("Branch is renamed, but update of config-file failed"));
-	if (copy && strcmp(oldname, newname) && git_config_copy_section(oldsection.buf, newsection.buf) < 0)
+	if (copy && strcmp(interpreted_oldname, interpreted_newname) && git_config_copy_section(oldsection.buf, newsection.buf) < 0)
 		die(_("Branch is copied, but update of config-file failed"));
+	strbuf_release(&oldref);
+	strbuf_release(&newref);
 	strbuf_release(&oldsection);
 	strbuf_release(&newsection);
 }

t/t3204-branch-name-interpretation.sh

@@ -57,6 +57,16 @@ test_expect_success 'create branch with pseudo-qualified name' '
 	expect_branch refs/heads/refs/heads/qualified two
 '
 
+test_expect_success 'force-copy a branch to itself via @{-1} is no-op' '
+	git branch -t copiable main &&
+	git checkout copiable &&
+	git checkout - &&
+	git branch -C @{-1} copiable &&
+	git config --get-all branch.copiable.merge >actual &&
+	echo refs/heads/main >expect &&
+	test_cmp expect actual
+'
+
 test_expect_success 'delete branch via @{-1}' '
 	git branch previous-del &&