Merge branch 'jc/branch-description-unset' into maint-2.38

"GIT_EDITOR=: git branch --edit-description" resulted in failure,
which has been corrected.

* jc/branch-description-unset:
  branch: do not fail a no-op --edit-desc

Author: gitster

builtin/branch.c

@@ -599,10 +599,11 @@ static GIT_PATH_FUNC(edit_description, "EDIT_DESCRIPTION")
 
 static int edit_branch_description(const char *branch_name)
 {
+	int exists;
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf name = STRBUF_INIT;
 
-	read_branch_desc(&buf, branch_name);
+	exists = !read_branch_desc(&buf, branch_name);
 	if (!buf.len || buf.buf[buf.len-1] != '\n')
 		strbuf_addch(&buf, '\n');
 	strbuf_commented_addf(&buf,
@@ -619,7 +620,8 @@ static int edit_branch_description(const char *branch_name)
 	strbuf_stripspace(&buf, 1);
 
 	strbuf_addf(&name, "branch.%s.description", branch_name);
-	git_config_set(name.buf, buf.len ? buf.buf : NULL);
+	if (buf.len || exists)
+		git_config_set(name.buf, buf.len ? buf.buf : NULL);
 	strbuf_release(&name);
 	strbuf_release(&buf);
 

t/t3200-branch.sh

@@ -1382,6 +1382,9 @@ test_expect_success 'branch --delete --force removes dangling branch' '
 '
 
 test_expect_success 'use --edit-description' '
+	EDITOR=: git branch --edit-description &&
+	test_must_fail git config branch.main.description &&
+
 	write_script editor <<-\EOF &&
 		echo "New contents" >"$1"
 	EOF