Merge branch 'ps/includeif-onbranch-cornercase-fix'

"git --git-dir=nowhere cmd" failed to properly notice that it
wasn't in any repository while processing includeIf.onbranch
configuration and instead crashed.

* ps/includeif-onbranch-cornercase-fix:
  config: fix evaluating "onbranch" with nonexistent git dir
  t1305: exercise edge cases of "onbranch" includes

Author: gitster

config.c

@@ -306,13 +306,16 @@ static int include_by_branch(struct config_include_data *data,
 	int flags;
 	int ret;
 	struct strbuf pattern = STRBUF_INIT;
-	const char *refname = (!data->repo || !data->repo->gitdir) ?
-		NULL : refs_resolve_ref_unsafe(get_main_ref_store(data->repo),
-					       "HEAD", 0, NULL, &flags);
-	const char *shortname;
+	const char *refname, *shortname;
 
-	if (!refname || !(flags & REF_ISSYMREF)	||
-			!skip_prefix(refname, "refs/heads/", &shortname))
+	if (!data->repo || data->repo->ref_storage_format == REF_STORAGE_FORMAT_UNKNOWN)
+		return 0;
+
+	refname = refs_resolve_ref_unsafe(get_main_ref_store(data->repo),
+					  "HEAD", 0, NULL, &flags);
+	if (!refname ||
+	    !(flags & REF_ISSYMREF) ||
+	    !skip_prefix(refname, "refs/heads/", &shortname))
 		return 0;
 
 	strbuf_add(&pattern, cond, cond_len);

t/t1305-config-include.sh

@@ -357,4 +357,44 @@ test_expect_success 'include cycles are detected' '
 	grep "exceeded maximum include depth" stderr
 '
 
+test_expect_success 'onbranch with unborn branch' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		git config set includeIf.onbranch:"*".path config.inc &&
+		git config set -f .git/config.inc foo.bar baz &&
+		git config get foo.bar
+	)
+'
+
+test_expect_success 'onbranch with detached HEAD' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		git config set "includeIf.onbranch:*.path" config.inc &&
+		git config set -f .git/config.inc foo.bar baz &&
+		test_commit initial &&
+		git switch --detach HEAD &&
+		test_must_fail git config get foo.bar
+	)
+'
+
+test_expect_success 'onbranch without repository' '
+	test_when_finished "rm -f .gitconfig config.inc" &&
+	git config set -f .gitconfig "includeIf.onbranch:**.path" config.inc &&
+	git config set -f config.inc foo.bar baz &&
+	git config get foo.bar &&
+	test_must_fail nongit git config get foo.bar
+'
+
+test_expect_success 'onbranch without repository but explicit nonexistent Git directory' '
+	test_when_finished "rm -f .gitconfig config.inc" &&
+	git config set -f .gitconfig "includeIf.onbranch:**.path" config.inc &&
+	git config set -f config.inc foo.bar baz &&
+	git config get foo.bar &&
+	test_must_fail nongit git --git-dir=nonexistent config get foo.bar
+'
+
 test_done