From 4a51ea4b81f2e3bc812ebd2b7ef9e6b4b295f1bf Mon Sep 17 00:00:00 2001
From: Stefan Marr <gron@php.net>
Date: Mon, 15 Aug 2011 22:16:58 +0000
Subject: [PATCH] Bug #55424	Fatal error when calling a method from a trait
 that is defined in parent class and required by using an abstract method in
 the trait. # The method got unconditionally deleted from the class, since it
 was assumed that we override it, but we did not in case of abstract methods
 coming from a trait. Thus, dont delete when we try to merge in an abstract
 method.

---
 Zend/tests/traits/bug55424.phpt | 35 +++++++++++++++++++++++++++++++++
 Zend/zend_compile.c             | 11 +++++++----
 2 files changed, 42 insertions(+), 4 deletions(-)
 create mode 100644 Zend/tests/traits/bug55424.phpt

diff --git a/Zend/tests/traits/bug55424.phpt b/Zend/tests/traits/bug55424.phpt
new file mode 100644
index 0000000000..b6c3b54515
--- /dev/null
+++ b/Zend/tests/traits/bug55424.phpt
@@ -0,0 +1,35 @@
+--TEST--
+Bug #55424 (Method got missing from class when a trait defined an abstract method to express a requirement)
+--FILE--
+<?php
+
+	trait ATrait
+	{
+		function setRequired()
+		{
+			$this->setAttribute();
+		}
+
+		abstract function setAttribute();
+	}	
+
+	class Base
+	{
+		function setAttribute() { }
+	}
+
+	class MyClass extends Base
+	{
+		use ATrait;
+	}
+
+	$i = new Base();
+	$i->setAttribute();
+
+	$t = new MyClass();
+	/* setAttribute used to disappear for no good reason. */
+	$t->setRequired();
+	echo 'DONE';
+?>
+--EXPECT--
+DONE
diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index 59e0193194..cd883cbe6f 100644
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -3635,10 +3635,13 @@ static int zend_traits_merge_functions_to_class(zend_function *fn TSRMLS_DC, int
 	} else if (existing_fn->common.scope != ce) {
 		add = 1; /* or inherited from other class or interface */
 		/* it is just a reference which was added to the subclass while doing the inheritance */
-		/* prototype = existing_fn; */
-		/* memory is scrambled anyway???? */
-		/* function_add_ref(prototype);  */
-		zend_hash_quick_del(&ce->function_table, hash_key->arKey, hash_key->nKeyLength, hash_key->h);
+		/* so we can deleted now, and will add the overriding method afterwards */
+
+		/* except, if we try to add an abstract function, then we should not delete the inherited one */
+		/* delete inherited fn if the function to be added is not abstract */
+		if ((fn->common.fn_flags & ZEND_ACC_ABSTRACT) == 0) {
+			zend_hash_quick_del(&ce->function_table, hash_key->arKey, hash_key->nKeyLength, hash_key->h);
+		}
 	}
 
 	if (add) {
-- 
2.40.0