[RFC 5/7] http: send Git-Protocol-Version header

[Brandon Williams <bmwill@google.com>]

Tell a serve that protocol v2 can be used by sending an http header
indicating this.

Signed-off-by: Brandon Williams <bmwill@google.com>
---
 http.c                      | 7 +++++++
 t/t5551-http-fetch-smart.sh | 2 ++
 2 files changed, 9 insertions(+)

diff --git a/http.c b/http.c
index fa8666a21..504a14a5a 100644
--- a/http.c
+++ b/http.c
@@ -896,6 +896,11 @@ static void set_from_env(const char **var, const char *envname)
 		*var = val;
 }
 
+static const char *get_version(void)
+{
+	return "Git-Protocol-Version: 2";
+}
+
 void http_init(struct remote *remote, const char *url, int proactive_auth)
 {
 	char *low_speed_limit;
@@ -926,6 +931,8 @@ void http_init(struct remote *remote, const char *url, int proactive_auth)
 	if (remote)
 		var_override(&http_proxy_authmethod, remote->http_proxy_authmethod);
 
+	extra_http_headers = curl_slist_append(extra_http_headers, get_version());
+
 	pragma_header = curl_slist_append(http_copy_default_headers(),
 		"Pragma: no-cache");
 	no_pragma_header = curl_slist_append(http_copy_default_headers(),
diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh
index a51b7e20d..ce13f2425 100755
--- a/t/t5551-http-fetch-smart.sh
+++ b/t/t5551-http-fetch-smart.sh
@@ -27,6 +27,7 @@ cat >exp <<EOF
 > GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1
 > Accept: */*
 > Accept-Encoding: gzip
+> Git-Protocol-Version: 2
 > Pragma: no-cache
 < HTTP/1.1 200 OK
 < Pragma: no-cache
@@ -34,6 +35,7 @@ cat >exp <<EOF
 < Content-Type: application/x-git-upload-pack-advertisement
 > POST /smart/repo.git/git-upload-pack HTTP/1.1
 > Accept-Encoding: gzip
+> Git-Protocol-Version: 2
 > Content-Type: application/x-git-upload-pack-request
 > Accept: application/x-git-upload-pack-result
 > Content-Length: xxx
-- 
2.14.1.342.g6490525c54-goog