curl: fix integer constant typechecks with curl_easy_setopt()

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 <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

http-push.c

@@ -194,7 +194,7 @@ 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);

http.c

@@ -744,7 +744,7 @@ static int has_proxy_cert_password(void)
 #ifdef GITCURL_HAVE_CURLOPT_TCP_KEEPALIVE
 static void set_curl_keepalive(CURL *c)
 {
-	curl_easy_setopt(c, CURLOPT_TCP_KEEPALIVE, 1);
+	curl_easy_setopt(c, CURLOPT_TCP_KEEPALIVE, 1L);
 }
 
 #else
@@ -1071,13 +1071,13 @@ 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);
 	}
 
 #ifdef GIT_CURL_HAVE_CURL_HTTP_VERSION_2
@@ -1192,7 +1192,7 @@ 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
@@ -1226,7 +1226,7 @@ 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);

remote-curl.c

@@ -876,12 +876,12 @@ 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);