remote-curl: ensure that URLs have a trailing slash

Previously, we blindly assumed that URLs passed to the remote-curl
helper did not end with a trailing slash.

Use the convenience function end_url_with_slash() from http.[ch] to
ensure that URLs have a trailing slash on invocation of the remote-curl
helper, and use the URL as one with a trailing slash throughout.

It is possible for users to pass a URL with a trailing slash to
remote-curl, by, say, setting it in remote.<name>.url in their git
config. The resulting requests have an empty path component (//) and may
break implementations of the http git protocol.

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote-curl.c

diff --git a/remote-curl.c b/remote-curl.c
index a904164..1fe59d6 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -9,7 +9,7 @@
 #include "sideband.h"
 
 static struct remote *remote;
-static const char *url;
+static const char *url; /* always ends with a trailing slash */
 static struct walker *walker;
 
 struct options {
@@ -108,7 +108,7 @@
 		return last;
 	free_discovery(last);
 
-	strbuf_addf(&buffer, "%s/info/refs", url);
+	strbuf_addf(&buffer, "%sinfo/refs", url);
 	if (!prefixcmp(url, "http://") || !prefixcmp(url, "https://")) {
 		is_http = 1;
 		if (!strchr(url, '?'))
@@ -128,7 +128,7 @@
 		strbuf_reset(&buffer);
 
 		proto_git_candidate = 0;
-		strbuf_addf(&buffer, "%s/info/refs", url);
+		strbuf_addf(&buffer, "%sinfo/refs", url);
 		refs_url = strbuf_detach(&buffer, NULL);
 
 		http_ret = http_get_strbuf(refs_url, &buffer, HTTP_NO_CACHE);
@@ -518,7 +518,7 @@
 	rpc->out = client.out;
 	strbuf_init(&rpc->result, 0);
 
-	strbuf_addf(&buf, "%s/%s", url, svc);
+	strbuf_addf(&buf, "%s%s", url, svc);
 	rpc->service_url = strbuf_detach(&buf, NULL);
 
 	strbuf_addf(&buf, "Content-Type: application/x-%s-request", svc);
@@ -805,11 +805,13 @@
 	remote = remote_get(argv[1]);
 
 	if (argc > 2) {
-		url = argv[2];
+		end_url_with_slash(&buf, argv[2]);
 	} else {
-		url = remote->url[0];
+		end_url_with_slash(&buf, remote->url[0]);
 	}
 
+	url = strbuf_detach(&buf, NULL);
+
 	do {
 		if (strbuf_getline(&buf, stdin, '\n') == EOF)
 			break;

t/t5541-http-push.sh

diff --git a/t/t5541-http-push.sh b/t/t5541-http-push.sh
index 7873d94..f0c50d3 100755
--- a/t/t5541-http-push.sh
+++ b/t/t5541-http-push.sh
@@ -38,7 +38,7 @@
 GET  /smart/test_repo.git/info/refs?service=git-upload-pack HTTP/1.1 200
 POST /smart/test_repo.git/git-upload-pack HTTP/1.1 200
 EOF
-test_expect_failure 'no empty path components' '
+test_expect_success 'no empty path components' '
 	# In the URL, add a trailing slash, and see if git appends yet another
 	# slash.
 	cd "$ROOT_PATH" &&