Add support for CURLINFO_CONN_ID in curl_getinfo()

UPGRADING

@@ -182,6 +182,11 @@ PHP 8.5 UPGRADE NOTES
     first redirect thus if there is any follow up redirect, it won't go
     any further. CURLFOLLOW_ALL is equivalent to setting CURLOPT_FOLLOWLOCATION
     to true.
+  . Added support for CURLINFO_CONN_ID (libcurl >= 8.2.0) to the curl_getinfo()
+    function. This constant allows retrieving the unique ID of the connection
+    used by a cURL transfer. It is primarily useful when connection reuse or
+    connection pooling logic is needed in PHP-level applications. When
+    curl_getinfo() returns an array, this value is available as the "conn_id" key.
 
 - DOM:
   . Added Dom\Element::$outerHTML.
@@ -483,6 +488,7 @@ PHP 8.5 UPGRADE NOTES
   . CURLINFO_USED_PROXY.
   . CURLINFO_HTTPAUTH_USED.
   . CURLINFO_PROXYAUTH_USED.
+  . CURLINFO_CONN_ID.
   . CURLOPT_INFILESIZE_LARGE.
   . CURLFOLLOW_ALL.
   . CURLFOLLOW_OBEYCODE.

ext/curl/curl.stub.php

@@ -3103,6 +3103,13 @@
  */
 const CURLINFO_POSTTRANSFER_TIME_T = UNKNOWN;
 #endif
+#if LIBCURL_VERSION_NUM >= 0x080200 /* Available since 8.2.0 */
+/**
+ * @var int
+ * @cvalue CURLINFO_CONN_ID
+ */
+const CURLINFO_CONN_ID = UNKNOWN;
+#endif
 /**
  * @var int
  * @cvalue CURLOPT_DISALLOW_USERNAME_IN_URL

ext/curl/interface.c

@@ -2691,6 +2691,11 @@ PHP_FUNCTION(curl_getinfo)
 		if (curl_easy_getinfo(ch->cp, CURLINFO_PROXYAUTH_USED, &l_code) == CURLE_OK) {
 			CAAL("proxyauth_used", l_code);
 		}
+#endif
+#if LIBCURL_VERSION_NUM >= 0x080200 /* Available since 8.2.0 */
+		if (curl_easy_getinfo(ch->cp, CURLINFO_CONN_ID , &co) == CURLE_OK) {
+			CAAL("conn_id", co);
+		}
 #endif
 	} else {
 		switch (option) {

ext/curl/tests/curl_getinfo_CURLINFO_CONN_ID.phpt

@@ -0,0 +1,56 @@
+--TEST--
+Curlinfo CURLINFO_CONN_ID
+--EXTENSIONS--
+curl
+--SKIPIF--
+<?php
+$curl_version = curl_version();
+if ($curl_version['version_number'] < 0x080200) die("skip: test works only with curl >= 8.2.0");
+?>
+--FILE--
+<?php
+include 'server.inc';
+
+$host = curl_cli_server_start();
+$port = (int) (explode(':', $host))[1];
+
+$ch = curl_init();
+curl_setopt($ch, CURLOPT_URL, "{$host}/get.inc?test=get");
+curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
+
+$info = curl_getinfo($ch);
+var_dump(isset($info['conn_id']));
+var_dump($info['conn_id'] === -1);
+
+$result = curl_exec($ch);
+
+$info = curl_getinfo($ch);
+var_dump(isset($info['conn_id']));
+var_dump(is_int($info['conn_id']));
+var_dump(curl_getinfo($ch, CURLINFO_CONN_ID) === $info['conn_id']);
+var_dump(curl_getinfo($ch, CURLINFO_CONN_ID) === 0);
+
+curl_setopt($ch, CURLOPT_URL, "{$host}/get.inc?test=get");
+curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
+$result = curl_exec($ch);
+
+$info = curl_getinfo($ch);
+var_dump(isset($info['conn_id']));
+var_dump(is_int($info['conn_id']));
+var_dump(curl_getinfo($ch, CURLINFO_CONN_ID) === $info['conn_id']);
+var_dump(curl_getinfo($ch, CURLINFO_CONN_ID) === 1);
+
+
+?>
+--EXPECT--
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+