[PATCH v2 1/4] curl: fix integer constant typechecks with curl_easy_setopt()

From: Jeff King via GitGitGadget <gitgitgadget@gmail.com>
Date: Jun 6, 2025, 09:29 UTC
Message-ID: <6f11c42e8edc5cf7d65156c9dd68e720f1b92229.1749202164.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.1931.v2.git.1749202164.gitgitgadget@gmail.com>

From: Jeff King <peff@peff.net>

The curl documentation specifies that curl_easy_setopt() takes either:

  ...a long, a function pointer, an object pointer or a curl_off_t,
  depending on what the specific option expects.

But when we pass an integer constant like "0", it will by default be a regular non-long int. This has always been wrong, but seemed to work in practice (I didn't dig into curl's implementation to see whether this might actually be triggering undefined behavior, but it seems likely and regardless we should do what the docs say).

This is especially important since curl has a type-checking macro that causes building against curl 8.14 to produce many warnings. The specific commit is due to their 79b4e56b3 (typecheck-gcc.h: fix the typechecks, 2025-04-22). Curiously, it does only seem to trigger when compiled with -O2 for me.

We can fix it by just marking the constants with a long "L".

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 http-push.c   |  2 +-
 http.c        | 14 +++++++-------
 remote-curl.c |  6 +++---
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/http-push.c b/http-push.c
index f9e67cabd4be..591e46ab260d 100644
--- a/http-push.c
+++ b/http-push.c
@@ -195,7 +195,7 @@ static char *xml_entities(const char *s)
 static void curl_setup_http_get(CURL *curl, const char *url,
 		const char *custom_req)
 {
-	curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
+	curl_easy_setopt(curl, CURLOPT_HTTPGET, 1L);
 	curl_easy_setopt(curl, CURLOPT_URL, url);
 	curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, custom_req);
 	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite_null);
diff --git a/http.c b/http.c
index 3c029cf8947d..cce2ea728736 100644
--- a/http.c
+++ b/http.c
@@ -1019,13 +1019,13 @@ static CURL *get_curl_handle(void)
 		die("curl_easy_init failed");
 
 	if (!curl_ssl_verify) {
-		curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 0);
-		curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 0);
+		curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 0L);
+		curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 0L);
 	} else {
 		/* Verify authenticity of the peer's certificate */
-		curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 1);
+		curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 1L);
 		/* The name in the cert must match whom we tried to connect */
-		curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2);
+		curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2L);
 	}
 
     if (curl_http_version) {
@@ -1117,7 +1117,7 @@ static CURL *get_curl_handle(void)
 				 curl_low_speed_time);
 	}
 
-	curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20);
+	curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20L);
 	curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
 
 #ifdef GIT_CURL_HAVE_CURLOPT_PROTOCOLS_STR
@@ -1151,7 +1151,7 @@ static CURL *get_curl_handle(void)
 		user_agent ? user_agent : git_user_agent());
 
 	if (curl_ftp_no_epsv)
-		curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0);
+		curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0L);
 
 	if (curl_ssl_try)
 		curl_easy_setopt(result, CURLOPT_USE_SSL, CURLUSESSL_TRY);
@@ -1254,7 +1254,7 @@ static CURL *get_curl_handle(void)
 	}
 	init_curl_proxy_auth(result);
 
-	curl_easy_setopt(result, CURLOPT_TCP_KEEPALIVE, 1);
+	curl_easy_setopt(result, CURLOPT_TCP_KEEPALIVE, 1L);
 
 	if (curl_tcp_keepidle > -1)
 		curl_easy_setopt(result, CURLOPT_TCP_KEEPIDLE,
diff --git a/remote-curl.c b/remote-curl.c
index 590b228f67fc..6183772191f2 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -877,12 +877,12 @@ static int probe_rpc(struct rpc_state *rpc, struct slot_results *results)
 	headers = curl_slist_append(headers, rpc->hdr_content_type);
 	headers = curl_slist_append(headers, rpc->hdr_accept);
 
-	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
-	curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
+	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0L);
+	curl_easy_setopt(slot->curl, CURLOPT_POST, 1L);
 	curl_easy_setopt(slot->curl, CURLOPT_URL, rpc->service_url);
 	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, NULL);
 	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, "0000");
-	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, 4);
+	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, 4L);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, &buf);

-- 
gitgitgadget