Answer dumb-clone HEAD from the ref store

A reftable repository keeps only a placeholder in its HEAD file, so a
dumb clone was told HEAD named refs/heads/.invalid and checked nothing
out. HEAD is now answered the way git's http-backend answers it.

2 files changed, 53 insertions, 5 deletions

diff --git a/source/ui-clone.c b/source/ui-clone.cindex fcab846..610aaa6 100644--- a/source/ui-clone.c+++ b/source/ui-clone.c@@ -186,11 +186,33 @@ err: 	cgit_print_error_page(400, "Bad Request", "Bad request"); } +/*+ * HEAD is answered from the ref store, the way git's own http-backend answers+ * it, rather than read off the disk, where a reftable repository keeps only a+ * placeholder. The target need not exist yet, so an empty repository still+ * names the branch a first push will create.+ */ void cgit_clone_head(void) {-	char *path;--	path = repo_git_path(the_repository, "HEAD");-	send_file(path);-	free(path);+	struct strbuf head = STRBUF_INIT;+	struct object_id oid;+	const char *target;+	int flags;++	target = refs_resolve_ref_unsafe(get_main_ref_store(the_repository), "HEAD", 0, &oid,+		&flags);+	if (!target) {+		cgit_print_error_page(404, "Not Found", "Not found");+		return;+	}+	if (flags & REF_ISSYMREF)+		strbuf_addf(&head, "ref: %s\n", target);+	else+		strbuf_addf(&head, "%s\n", oid_to_hex(&oid));+	ctx.page.mimetype = "text/plain";+	ctx.page.filename = "HEAD";+	ctx.page.size = head.len;+	cgit_print_http_headers();+	html_raw(head.buf, head.len);+	strbuf_release(&head); }
diff --git a/source/ui-clone.c b/source/ui-clone.c
index fcab846..610aaa6 100644
--- a/source/ui-clone.c
+++ b/source/ui-clone.c
@@ -186,11 +186,33 @@ err:
 	cgit_print_error_page(400, "Bad Request", "Bad request");
 }
 
+/*
+ * HEAD is answered from the ref store, the way git's own http-backend answers
+ * it, rather than read off the disk, where a reftable repository keeps only a
+ * placeholder. The target need not exist yet, so an empty repository still
+ * names the branch a first push will create.
+ */
 void cgit_clone_head(void)
 {
-	char *path;
-
-	path = repo_git_path(the_repository, "HEAD");
-	send_file(path);
-	free(path);
+	struct strbuf head = STRBUF_INIT;
+	struct object_id oid;
+	const char *target;
+	int flags;
+
+	target = refs_resolve_ref_unsafe(get_main_ref_store(the_repository), "HEAD", 0, &oid,
+		&flags);
+	if (!target) {
+		cgit_print_error_page(404, "Not Found", "Not found");
+		return;
+	}
+	if (flags & REF_ISSYMREF)
+		strbuf_addf(&head, "ref: %s\n", target);
+	else
+		strbuf_addf(&head, "%s\n", oid_to_hex(&oid));
+	ctx.page.mimetype = "text/plain";
+	ctx.page.filename = "HEAD";
+	ctx.page.size = head.len;
+	cgit_print_http_headers();
+	html_raw(head.buf, head.len);
+	strbuf_release(&head);
 }
diff --git a/tests/t0303-robustness.sh b/tests/t0303-robustness.shindex da5e209..14bdca7 100755--- a/tests/t0303-robustness.sh+++ b/tests/t0303-robustness.sh@@ -590,6 +590,32 @@ test_expect_success 'the dumb transport withholds the alternates file' ' 	grep "^Status: 200" tmp ' +# A reftable repository keeps only a placeholder in its HEAD file, so the+# branch a client is to check out has to come from the refs instead.+test_expect_success 'the dumb transport answers HEAD from the refs' '+	robq "url=rob/HEAD" >tmp &&+	grep "^Status: 200" tmp &&+	strip_headers <tmp >head &&+	echo "ref: refs/heads/master" >expect &&+	test_cmp expect head &&+	git init -q --bare --ref-format=reftable -b trunk rt.git &&+	git -C repos/rob push -q "$PWD/rt.git" master:trunk &&+	{+		echo "virtual-root=/" &&+		echo "cache-size=0" &&+		echo "repo.url=rt" &&+		echo "repo.path=$PWD/rt.git"+	} >rtrc &&+	CGIT_CONFIG="$PWD/rtrc" QUERY_STRING="url=rt/HEAD" cgit >tmp &&+	strip_headers <tmp >head &&+	echo "ref: refs/heads/trunk" >expect &&+	test_cmp expect head &&+	CGIT_CONFIG="$PWD/emptyrc" QUERY_STRING="url=empty/HEAD" cgit >tmp &&+	strip_headers <tmp >head &&+	echo "ref: refs/heads/master" >expect &&+	test_cmp expect head+'+ # A client that goes away mid-page leaves nobody to send an error page to, # so the request ends quietly instead of dying twice into the log. The page # has to outgrow the pipe for the write after the reader has gone to fail.
diff --git a/tests/t0303-robustness.sh b/tests/t0303-robustness.sh
index da5e209..14bdca7 100755
--- a/tests/t0303-robustness.sh
+++ b/tests/t0303-robustness.sh
@@ -590,6 +590,32 @@ test_expect_success 'the dumb transport withholds the alternates file' '
 	grep "^Status: 200" tmp
 '
 
+# A reftable repository keeps only a placeholder in its HEAD file, so the
+# branch a client is to check out has to come from the refs instead.
+test_expect_success 'the dumb transport answers HEAD from the refs' '
+	robq "url=rob/HEAD" >tmp &&
+	grep "^Status: 200" tmp &&
+	strip_headers <tmp >head &&
+	echo "ref: refs/heads/master" >expect &&
+	test_cmp expect head &&
+	git init -q --bare --ref-format=reftable -b trunk rt.git &&
+	git -C repos/rob push -q "$PWD/rt.git" master:trunk &&
+	{
+		echo "virtual-root=/" &&
+		echo "cache-size=0" &&
+		echo "repo.url=rt" &&
+		echo "repo.path=$PWD/rt.git"
+	} >rtrc &&
+	CGIT_CONFIG="$PWD/rtrc" QUERY_STRING="url=rt/HEAD" cgit >tmp &&
+	strip_headers <tmp >head &&
+	echo "ref: refs/heads/trunk" >expect &&
+	test_cmp expect head &&
+	CGIT_CONFIG="$PWD/emptyrc" QUERY_STRING="url=empty/HEAD" cgit >tmp &&
+	strip_headers <tmp >head &&
+	echo "ref: refs/heads/master" >expect &&
+	test_cmp expect head
+'
+
 # A client that goes away mid-page leaves nobody to send an error page to,
 # so the request ends quietly instead of dying twice into the log. The page
 # has to outgrow the pipe for the write after the reader has gone to fail.