Add reproducer for possible issue with object return type inheritance

Zend/tests/internal_class_variance.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Internal class variance
+--EXTENSIONS--
+zend_test
+--FILE--
+<?php
+$test = new _ZendTestChildClass;
+
+try {
+    $test->returnsThrowable();
+} catch (\Error) {
+    echo "OK";
+}
+?>
+--EXPECT--
+OK

Zend/zend_inheritance.c

@@ -200,22 +200,45 @@ static bool class_visible(zend_class_entry *ce) {
 	}
 }
 
+static zend_always_inline void register_unresolved_class(zend_string *name) {
+	/* We'll autoload this class and process delayed variance obligations later. */
+	if (!CG(delayed_autoloads)) {
+		ALLOC_HASHTABLE(CG(delayed_autoloads));
+		zend_hash_init(CG(delayed_autoloads), 0, NULL, NULL, 0);
+	}
+	zend_hash_add_empty_element(CG(delayed_autoloads), name);
+}
+
 static zend_class_entry *lookup_class(
 		zend_class_entry *scope, zend_string *name, bool register_unresolved) {
-	uint32_t flags = ZEND_FETCH_CLASS_ALLOW_UNLINKED | ZEND_FETCH_CLASS_NO_AUTOLOAD;
-	zend_class_entry *ce = zend_lookup_class_ex(name, NULL, flags);
+	zend_class_entry *ce;
+
+	if (UNEXPECTED(!EG(active))) {
+		zend_string *lc_name = zend_string_tolower(name);
+
+		ce = zend_hash_find_ptr(CG(class_table), lc_name);
+
+		zend_string_release(lc_name);
+
+		if (register_unresolved && !ce) {
+			zend_error_noreturn(
+				E_COMPILE_ERROR, "%s must be registered before %s",
+				ZSTR_VAL(name), ZSTR_VAL(scope->name));
+	    }
+
+		return ce;
+	}
+
+	ce = zend_lookup_class_ex(
+	    name, NULL, ZEND_FETCH_CLASS_ALLOW_UNLINKED | ZEND_FETCH_CLASS_NO_AUTOLOAD);
+
 	if (!CG(in_compilation)) {
 		if (ce) {
 			return ce;
 		}
 
 		if (register_unresolved) {
-			/* We'll autoload this class and process delayed variance obligations later. */
-			if (!CG(delayed_autoloads)) {
-				ALLOC_HASHTABLE(CG(delayed_autoloads));
-				zend_hash_init(CG(delayed_autoloads), 0, NULL, NULL, 0);
-			}
-			zend_hash_add_empty_element(CG(delayed_autoloads), name);
+			register_unresolved_class(name);
 		}
 	} else {
 		if (ce && class_visible(ce)) {

ext/zend_test/test.c

@@ -257,22 +257,25 @@ static zend_object *zend_test_class_new(zend_class_entry *class_type) /* {{{ */
 /* }}} */
 
 static zend_function *zend_test_class_method_get(zend_object **object, zend_string *name, const zval *key) /* {{{ */ {
-	zend_internal_function *fptr;
-
-	if (EXPECTED(EG(trampoline).common.function_name == NULL)) {
-		fptr = (zend_internal_function *) &EG(trampoline);
-	} else {
-		fptr = emalloc(sizeof(zend_internal_function));
-	}
-	memset(fptr, 0, sizeof(zend_internal_function));
-	fptr->type = ZEND_INTERNAL_FUNCTION;
-	fptr->num_args = 1;
-	fptr->scope = (*object)->ce;
-	fptr->fn_flags = ZEND_ACC_CALL_VIA_HANDLER;
-	fptr->function_name = zend_string_copy(name);
-	fptr->handler = ZEND_FN(zend_test_func);
-
-	return (zend_function*)fptr;
+    if (zend_string_equals_literal_ci(name, "test")) {
+	    zend_internal_function *fptr;
+
+	    if (EXPECTED(EG(trampoline).common.function_name == NULL)) {
+		    fptr = (zend_internal_function *) &EG(trampoline);
+	    } else {
+		    fptr = emalloc(sizeof(zend_internal_function));
+	    }
+	    memset(fptr, 0, sizeof(zend_internal_function));
+	    fptr->type = ZEND_INTERNAL_FUNCTION;
+	    fptr->num_args = 1;
+	    fptr->scope = (*object)->ce;
+	    fptr->fn_flags = ZEND_ACC_CALL_VIA_HANDLER;
+	    fptr->function_name = zend_string_copy(name);
+	    fptr->handler = ZEND_FN(zend_test_func);
+
+	    return (zend_function*)fptr;
+    }
+	return zend_std_get_method(object, name, key);
 }
 /* }}} */
 
@@ -322,6 +325,16 @@ static ZEND_METHOD(_ZendTestClass, returnsStatic) {
 	object_init_ex(return_value, zend_get_called_scope(execute_data));
 }
 
+static ZEND_METHOD(_ZendTestClass, returnsThrowable) {
+	ZEND_PARSE_PARAMETERS_NONE();
+	zend_throw_error(NULL, "Dummy");
+}
+
+static ZEND_METHOD(_ZendTestChildClass, returnsThrowable) {
+	ZEND_PARSE_PARAMETERS_NONE();
+	zend_throw_error(NULL, "Dummy");
+}
+
 static ZEND_METHOD(_ZendTestTrait, testMethod) {
 	ZEND_PARSE_PARAMETERS_NONE();
 	RETURN_TRUE;

ext/zend_test/test.stub.php

@@ -24,10 +24,13 @@ public static function is_object(): int {}
     public function __toString(): string {}
 
     public function returnsStatic(): static {}
+
+    public function returnsThrowable(): Throwable {}
 }
 
 class _ZendTestChildClass extends _ZendTestClass
 {
+    public function returnsThrowable(): Exception {}
 }
 
 trait _ZendTestTrait {

ext/zend_test/test_arginfo.h

@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: cf8958513064fb7257203b3304c8dc67c8e008b9 */
+ * Stub hash: 70374ed7b55604eb98e85148d7ff19e79258ce92 */
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_zend_test_array_return, 0, 0, IS_ARRAY, 0)
 ZEND_END_ARG_INFO()
@@ -63,6 +63,12 @@ ZEND_END_ARG_INFO()
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_class__ZendTestClass_returnsStatic, 0, 0, IS_STATIC, 0)
 ZEND_END_ARG_INFO()
 
+ZEND_BEGIN_ARG_WITH_RETURN_OBJ_INFO_EX(arginfo_class__ZendTestClass_returnsThrowable, 0, 0, Throwable, 0)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_WITH_RETURN_OBJ_INFO_EX(arginfo_class__ZendTestChildClass_returnsThrowable, 0, 0, Exception, 0)
+ZEND_END_ARG_INFO()
+
 #define arginfo_class__ZendTestTrait_testMethod arginfo_ZendTestNS2_ZendSubNS_namespaced_func
 
 #define arginfo_class_ZendTestNS_Foo_method arginfo_zend_test_void_return
@@ -89,6 +95,8 @@ static ZEND_FUNCTION(namespaced_func);
 static ZEND_METHOD(_ZendTestClass, is_object);
 static ZEND_METHOD(_ZendTestClass, __toString);
 static ZEND_METHOD(_ZendTestClass, returnsStatic);
+static ZEND_METHOD(_ZendTestClass, returnsThrowable);
+static ZEND_METHOD(_ZendTestChildClass, returnsThrowable);
 static ZEND_METHOD(_ZendTestTrait, testMethod);
 static ZEND_METHOD(ZendTestNS_Foo, method);
 static ZEND_METHOD(ZendTestNS2_Foo, method);
@@ -123,11 +131,13 @@ static const zend_function_entry class__ZendTestClass_methods[] = {
 	ZEND_ME(_ZendTestClass, is_object, arginfo_class__ZendTestClass_is_object, ZEND_ACC_PUBLIC|ZEND_ACC_STATIC)
 	ZEND_ME(_ZendTestClass, __toString, arginfo_class__ZendTestClass___toString, ZEND_ACC_PUBLIC|ZEND_ACC_DEPRECATED)
 	ZEND_ME(_ZendTestClass, returnsStatic, arginfo_class__ZendTestClass_returnsStatic, ZEND_ACC_PUBLIC)
+	ZEND_ME(_ZendTestClass, returnsThrowable, arginfo_class__ZendTestClass_returnsThrowable, ZEND_ACC_PUBLIC)
 	ZEND_FE_END
 };
 
 
 static const zend_function_entry class__ZendTestChildClass_methods[] = {
+	ZEND_ME(_ZendTestChildClass, returnsThrowable, arginfo_class__ZendTestChildClass_returnsThrowable, ZEND_ACC_PUBLIC)
 	ZEND_FE_END
 };