Fix inheritance of class constants if mutable data used

Class constants from parents should always be directly reused,
rather than re-evaluated as a separate copy. Previously this used
to happen automatically, as we'd just inherit the class constant
entry from the parent class. With mutable data there may now be
a separate copy of the constant, so we need to use that copy
when updating constants. Otherwise we may evaluate the same
constant multiple times.

Closes GH-7658.

Author: nikic

Zend/tests/class_constant_inheritance_mutable_data.phpt

@@ -0,0 +1,35 @@
+--TEST--
+Class constant inheritance with mutable data
+--FILE--
+<?php
+
+// This would previously leak under opcache.
+class A {
+    const X = 'X' . self::Y;
+    const Y = 'Y';
+}
+interface I {
+    const X2 = 'X2' . self::Y2;
+    const Y2 = 'Y2';
+}
+eval('class B extends A implements I {}');
+var_dump(new B);
+var_dump(B::X, B::X2);
+
+// This should only produce one warning, not two.
+class X {
+    const C = 1 % 1.5;
+}
+class Y extends X {
+}
+var_dump(X::C, Y::C);
+?>
+--EXPECTF--
+object(B)#1 (0) {
+}
+string(2) "XY"
+string(4) "X2Y2"
+
+Deprecated: Implicit conversion from float 1.5 to int loses precision in %s on line %d
+int(0)
+int(0)

Zend/zend_API.c

@@ -1322,12 +1322,19 @@ ZEND_API HashTable *zend_separate_class_constants_table(zend_class_entry *class_
 	zend_hash_extend(constants_table, zend_hash_num_elements(&class_type->constants_table), 0);
 
 	ZEND_HASH_FOREACH_STR_KEY_PTR(&class_type->constants_table, key, c) {
-		if (Z_TYPE(c->value) == IS_CONSTANT_AST) {
-			new_c = zend_arena_alloc(&CG(arena), sizeof(zend_class_constant));
-			memcpy(new_c, c, sizeof(zend_class_constant));
-			c = new_c;
+		if (c->ce == class_type) {
+			if (Z_TYPE(c->value) == IS_CONSTANT_AST) {
+				new_c = zend_arena_alloc(&CG(arena), sizeof(zend_class_constant));
+				memcpy(new_c, c, sizeof(zend_class_constant));
+				c = new_c;
+			}
+			Z_TRY_ADDREF(c->value);
+		} else {
+			if (Z_TYPE(c->value) == IS_CONSTANT_AST) {
+				c = zend_hash_find_ptr(CE_CONSTANTS_TABLE(c->ce), key);
+				ZEND_ASSERT(c);
+			}
 		}
-		Z_TRY_ADDREF(c->value);
 		_zend_hash_append_ptr(constants_table, key, c);
 	} ZEND_HASH_FOREACH_END();
 
@@ -1409,8 +1416,18 @@ ZEND_API zend_result zend_update_class_constants(zend_class_entry *class_type) /
 		} else {
 			constants_table = &class_type->constants_table;
 		}
-		ZEND_HASH_FOREACH_PTR(constants_table, c) {
+
+		zend_string *name;
+		ZEND_HASH_FOREACH_STR_KEY_VAL(constants_table, name, val) {
+			c = Z_PTR_P(val);
 			if (Z_TYPE(c->value) == IS_CONSTANT_AST) {
+				if (c->ce != class_type) {
+					Z_PTR_P(val) = c = zend_hash_find_ptr(CE_CONSTANTS_TABLE(c->ce), name);
+					if (Z_TYPE(c->value) != IS_CONSTANT_AST) {
+						continue;
+					}
+				}
+
 				val = &c->value;
 				if (UNEXPECTED(zval_update_constant_ex(val, c->ce) != SUCCESS)) {
 					return FAILURE;

Zend/zend_opcode.c

@@ -250,7 +250,9 @@ ZEND_API void zend_cleanup_mutable_class_data(zend_class_entry *ce)
 			zend_class_constant *c;
 
 			ZEND_HASH_FOREACH_PTR(constants_table, c) {
-				zval_ptr_dtor_nogc(&c->value);
+				if (c->ce == ce) {
+					zval_ptr_dtor_nogc(&c->value);
+				}
 			} ZEND_HASH_FOREACH_END();
 			zend_hash_destroy(constants_table);
 			mutable_data->constants_table = NULL;