ext/curl: fix CURLOPT_SEEKFUNCTION GC, reset and test issues

Register the seek callback with the cycle collector in curl_get_gc() so a
seek closure that captures its own handle can be collected, and free it in
_php_curl_reset_handlers() so curl_reset() clears it, matching the other
callbacks.

Drop the deprecated curl_close() call from curl_seekfunction.phpt, which
emitted an unexpected deprecation notice and failed the strict EXPECT, and
add a curl_copy_handle() test exercising the seek callback on a copied handle.

Author: GrahamCampbell

ext/curl/interface.c

@@ -456,6 +456,10 @@ static HashTable *curl_get_gc(zend_object *object, zval **table, int *n)
 		zend_get_gc_buffer_add_zval(gc_buffer, &curl->handlers.write_header->stream);
 	}
 
+	if (ZEND_FCC_INITIALIZED(curl->handlers.seek)) {
+		zend_get_gc_buffer_add_fcc(gc_buffer, &curl->handlers.seek);
+	}
+
 	if (ZEND_FCC_INITIALIZED(curl->handlers.progress)) {
 		zend_get_gc_buffer_add_fcc(gc_buffer, &curl->handlers.progress);
 	}
@@ -2920,6 +2924,10 @@ static void _php_curl_reset_handlers(php_curl *ch)
 		ZVAL_UNDEF(&ch->handlers.std_err);
 	}
 
+	if (ZEND_FCC_INITIALIZED(ch->handlers.seek)) {
+		zend_fcc_dtor(&ch->handlers.seek);
+	}
+
 	if (ZEND_FCC_INITIALIZED(ch->handlers.progress)) {
 		zend_fcc_dtor(&ch->handlers.progress);
 	}

ext/curl/tests/curl_copy_handle_seek.phpt

@@ -0,0 +1,44 @@
+--TEST--
+Test curl_copy_handle() preserves CURLOPT_SEEKFUNCTION
+--EXTENSIONS--
+curl
+--FILE--
+<?php
+include 'server.inc';
+$host = curl_cli_server_start();
+
+$body = 'Hello cURL seek!';
+$offset = 0;
+$seekCalls = 0;
+
+$ch = curl_init("{$host}/get.inc?test=redirect");
+curl_setopt($ch, CURLOPT_UPLOAD, true);
+curl_setopt($ch, CURLOPT_INFILESIZE, strlen($body));
+curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
+curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+curl_setopt($ch, CURLOPT_READFUNCTION, function ($ch, $fd, int $length) use ($body, &$offset) {
+    $chunk = substr($body, $offset, $length);
+    $offset += strlen($chunk);
+    return $chunk;
+});
+curl_setopt($ch, CURLOPT_SEEKFUNCTION, function ($ch, int $offset_, int $origin) use (&$offset, &$seekCalls) {
+    if ($origin !== SEEK_SET) {
+        return CURL_SEEKFUNC_CANTSEEK;
+    }
+    $seekCalls++;
+    $offset = $offset_;
+    return CURL_SEEKFUNC_OK;
+});
+
+// The copied handle must inherit the seek callback; exercise it on the copy
+// after freeing the original.
+$ch2 = curl_copy_handle($ch);
+unset($ch);
+
+$response = curl_exec($ch2);
+var_dump($seekCalls > 0);
+var_dump(str_contains($response, $body));
+?>
+--EXPECT--
+bool(true)
+bool(true)

ext/curl/tests/curl_seekfunction.phpt

@@ -35,7 +35,6 @@ $response = curl_exec($ch);
 // and the resent body must have reached the redirect target intact.
 var_dump($seekCalls > 0);
 var_dump(str_contains($response, $body));
-curl_close($ch);
 ?>
 --EXPECT--
 bool(true)