From 2adaa11f2fcab72bf8dc4b5d875ce084e9080caa Mon Sep 17 00:00:00 2001
From: Zeev Suraski <zeev@php.net>
Date: Wed, 28 Jan 2004 10:25:45 +0000
Subject: [PATCH] Prevent classes from implementing interfaces that have the
 same function

---
 Zend/zend_compile.c | 28 +++++++++++++++++++++++++++-
 Zend/zend_compile.h |  1 +
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index 35ad5e7e5d2..aae2eb4a75e 100644
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -1733,6 +1733,14 @@ static zend_bool do_inherit_method_check(HashTable *child_function_table, zend_f
 		return 1; /* method doesn't exist in child, copy from parent */
 	}
 
+	if (parent->common.fn_flags & ZEND_ACC_ABSTRACT
+		&& child->common.fn_flags & (ZEND_ACC_ABSTRACT|ZEND_ACC_IMPLEMENTED_ABSTRACT)) {
+		zend_error(E_COMPILE_ERROR, "Can't inherit abstract function %s::%s() (previously declared abstract in %s)", 
+			parent->common.scope->name,
+			child->common.function_name,
+			child->common.prototype->common.scope->name);
+	}
+
 	if (parent_flags & ZEND_ACC_FINAL) {
 		zend_error(E_COMPILE_ERROR, "Cannot override final method %s::%s()", ZEND_FN_SCOPE_NAME(parent), child->common.function_name);
 	}
@@ -1766,8 +1774,9 @@ static zend_bool do_inherit_method_check(HashTable *child_function_table, zend_f
 		}
 	}
 
-	if (parent_flags & (ZEND_ACC_ABSTRACT|ZEND_ACC_ABSTRACT)) {
+	if (parent_flags & ZEND_ACC_ABSTRACT) {
 		child->common.prototype = parent;
+		child->common.fn_flags |= ZEND_ACC_IMPLEMENTED_ABSTRACT;
 	} else if (parent->common.prototype) {
 		child->common.prototype = parent->common.prototype;
 	}
@@ -2427,6 +2436,23 @@ void zend_do_end_class_declaration(znode *class_token, znode *parent_token TSRML
 }
 
 
+#if 0
+/* This is a part of an incomplete patch, coming soon */
+ZEND_API void zend_do_extends(znode *result, znode *class_token, zend_bool is_first_parent TSRMLS_DC)
+{
+	zend_bool is_class = CG(active_class_entry)->ce_flags & ZEND_ACC_INTERFACE;
+
+	if (is_class) {
+		if (!is_first_parent) {
+			zend_error(E_COMPILE_ERROR, "Classes may extend only one parent");
+		} else {
+			*result = *class_token;
+		}
+	} else { /* interface */
+	}
+}
+#endif
+
 void zend_do_implements_interface(znode *interface_znode TSRMLS_DC)
 {
 	zend_op *opline = get_next_op(CG(active_op_array) TSRMLS_CC);
diff --git a/Zend/zend_compile.h b/Zend/zend_compile.h
index 8c2026dfe84..e90654b0981 100644
--- a/Zend/zend_compile.h
+++ b/Zend/zend_compile.h
@@ -100,6 +100,7 @@ typedef struct _zend_brk_cont_element {
 #define ZEND_ACC_INTERFACE		0x08
 #define ZEND_ACC_ABSTRACT_CLASS	0x10
 #define ZEND_ACC_FINAL_CLASS	0x20
+#define ZEND_ACC_IMPLEMENTED_ABSTRACT	0x40
 
 #define ZEND_ACC_ALLOW_STATIC	0x80