From 640657ffd06999ec1ec3b1d030b7f5aac6b7f57b Mon Sep 17 00:00:00 2001
From: Vaidas Pilkauskas <vaidas.pilkauskas@shopify.com>
Date: Tue, 17 Mar 2026 13:00:35 +0000
Subject: http: add support for HTTP 429 rate limit retries

Add retry logic for HTTP 429 (Too Many Requests) responses to handle
server-side rate limiting gracefully. When Git's HTTP client receives
a 429 response, it can now automatically retry the request after an
appropriate delay, respecting the server's rate limits.

The implementation supports the RFC-compliant Retry-After header in
both delay-seconds (integer) and HTTP-date (RFC 2822) formats. If a
past date is provided, Git retries immediately without waiting.

Retry behavior is controlled by three new configuration options
(http.maxRetries, http.retryAfter, and http.maxRetryTime) which are
documented in git-config(1).

The retry logic implements a fail-fast approach: if any delay
(whether from server header or configuration) exceeds maxRetryTime,
Git fails immediately with a clear error message rather than capping
the delay. This provides better visibility into rate limiting issues.

The implementation includes extensive test coverage for basic retry
behavior, Retry-After header formats (integer and HTTP-date),
configuration combinations, maxRetryTime limits, invalid header
handling, environment variable overrides, and edge cases.

Signed-off-by: Vaidas Pilkauskas <vaidas.pilkauskas@shopify.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/lib-httpd/apache.conf | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 't/lib-httpd/apache.conf')

diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
index e631ab0eb5..6bdef603cd 100644
--- a/t/lib-httpd/apache.conf
+++ b/t/lib-httpd/apache.conf
@@ -139,6 +139,10 @@ SetEnv PERL_PATH ${PERL_PATH}
 	SetEnv GIT_EXEC_PATH ${GIT_EXEC_PATH}
 	SetEnv GIT_HTTP_EXPORT_ALL
 </LocationMatch>
+<LocationMatch /http_429/>
+	SetEnv GIT_EXEC_PATH ${GIT_EXEC_PATH}
+	SetEnv GIT_HTTP_EXPORT_ALL
+</LocationMatch>
 <LocationMatch /smart_v0/>
 	SetEnv GIT_EXEC_PATH ${GIT_EXEC_PATH}
 	SetEnv GIT_HTTP_EXPORT_ALL
@@ -160,6 +164,7 @@ ScriptAlias /broken_smart/ broken-smart-http.sh/
 ScriptAlias /error_smart/ error-smart-http.sh/
 ScriptAlias /error/ error.sh/
 ScriptAliasMatch /one_time_script/(.*) apply-one-time-script.sh/$1
+ScriptAliasMatch /http_429/(.*) http-429.sh/$1
 ScriptAliasMatch /custom_auth/(.*) nph-custom-auth.sh/$1
 <Directory ${GIT_EXEC_PATH}>
 	Options FollowSymlinks
@@ -185,6 +190,9 @@ ScriptAliasMatch /custom_auth/(.*) nph-custom-auth.sh/$1
 <Files apply-one-time-script.sh>
 	Options ExecCGI
 </Files>
+<Files http-429.sh>
+	Options ExecCGI
+</Files>
 <Files ${GIT_EXEC_PATH}/git-http-backend>
 	Options ExecCGI
 </Files>
-- 
cgit v1.3-5-g9baa