Fix segfault on uv_fs_readlink() where target is not a link

package.xml

@@ -10,11 +10,11 @@
   <email>bobwei9@hotmail.com</email>
   <active>yes</active>
  </lead>
- <date>2019-04-28</date>
+ <date>2019-05-01</date>
  <time>13:00:00</time>
  <version>
-  <release>0.2.3</release>
+  <release>0.2.4</release>
-  <api>0.2.3</api>
+  <api>0.2.4</api>
  </version>
  <stability>
   <release>beta</release>
@@ -23,7 +23,6 @@
  <license uri="http://www.php.net/license">PHP License</license>
  <notes>
  - Fix Windows build
- - Fix PHP 7.4 build
  </notes>
  <contents>
   <dir name="/">

php_uv.c

@@ -1873,7 +1873,11 @@ static void php_uv_fs_cb(uv_fs_t* req)
 		case UV_FS_READLINK:
 			argc = 2;
 			ZVAL_BOOL(&params[0], uv->uv.fs.result == 0);
-			ZVAL_STRING(&params[1], req->ptr);
+			if (uv->uv.fs.result == 0) {
+				ZVAL_STRING(&params[1], req->ptr);
+			} else {
+				ZVAL_NULL(&params[1]);
+			}
 			break;
 
 		case UV_FS_READ:

php_uv.h

@@ -3,7 +3,7 @@
 #define PHP_UV_H
 
 #define PHP_UV_EXTNAME "uv"
-#define PHP_UV_VERSION "0.2.3"
+#define PHP_UV_VERSION "0.2.4"
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"

tests/320-fs-readlink.phpt

@@ -0,0 +1,22 @@
+--TEST--
+uv_fs_readlink() segfaults if file not a link
+--FILE--
+<?php
+
+$uv = uv_loop_new();
+
+uv_fs_readlink($uv, __FILE__, function () {
+    var_dump(func_get_args());
+});
+
+uv_run($uv);
+
+?>
+--EXPECT--
+array(2) {
+  [0]=>
+  bool(false)
+  [1]=>
+  NULL
+}
+