Fix bug #65579 (Using traits with get_class_methods causes segfault).

Specifically, this checks if there are trait aliases defined in the class scope
before attempting to dereference the first trait alias. This handles the case
where a trait alias was used in a child trait but no aliases exist in the
concrete class.

Author: LawnGnome

NEWS

@@ -3,6 +3,8 @@ PHP                                                                        NEWS
 ?? ??? 2013, PHP 5.4.20
 
 - Core:
+  . Fixed bug #65579 (Using traits with get_class_methods causes segfault).
+    (Adam)
   . Fixed bug #65490 (Duplicate calls to get lineno & filename for 
     DTRACE_FUNCTION_*). (Chris Jones)
   . Fixed bug #65483 (quoted-printable encode stream filter incorrectly encoding

Zend/tests/bug65579.phpt

@@ -0,0 +1,29 @@
+--TEST--
+Bug #65579 (Using traits with get_class_methods causes segfault)
+--FILE--
+<?php
+trait ParentTrait {
+    public function testMethod() { }
+}
+
+trait ChildTrait {
+    use ParentTrait {
+        testMethod as testMethodFromParentTrait;
+    }
+    public function testMethod() { }
+}
+
+class TestClass {
+    use ChildTrait;
+}
+
+$obj = new TestClass();
+var_dump(get_class_methods($obj));
+?>
+--EXPECT--
+array(2) {
+  [0]=>
+  string(10) "testMethod"
+  [1]=>
+  string(25) "testmethodfromparenttrait"
+}

Zend/zend_API.c

@@ -3917,15 +3917,16 @@ ZEND_API const char* zend_find_alias_name(zend_class_entry *ce, const char *name
 {
 	zend_trait_alias *alias, **alias_ptr;
 
-	alias_ptr = ce->trait_aliases;
-	alias = *alias_ptr;
-	while (alias) {
-		if (alias->alias_len == len &&
-		    !strncasecmp(name, alias->alias, alias->alias_len)) {
-			return alias->alias;
-		}
-		alias_ptr++;
+	if (alias_ptr = ce->trait_aliases) {
 		alias = *alias_ptr;
+		while (alias) {
+			if (alias->alias_len == len &&
+				!strncasecmp(name, alias->alias, alias->alias_len)) {
+				return alias->alias;
+			}
+			alias_ptr++;
+			alias = *alias_ptr;
+		}
 	}
 
 	return name;