fix: keep lazy init inside __get guard, move above deprecation checks

The previous commit hoisted the lazy init check above the __get guard
conditional, which caused proxy initialization even when __get should
handle the property access. Move the check back inside the guard but
before the deprecation/error handling so dynamic property deprecation
still only fires once (on the instance, not the proxy).

Add regression test for proxy-with-__get not initializing on dynamic
property access (from Ilija's review).

Author: iliaal

Zend/tests/lazy_objects/gh20875.phpt

@@ -31,6 +31,14 @@ Warning: Undefined variable $a in %s on line %d
 
 Warning: Undefined variable $v in %s on line %d
 
+Notice: Indirect modification of overloaded property A::$b has no effect in %s on line %d
+
+Warning: Undefined variable $x in %s on line %d
+
+Notice: Object of class stdClass could not be converted to int in %s on line %d
+
+Warning: Undefined variable $v in %s on line %d
+
 Notice: Indirect modification of overloaded property A::$f has no effect in %s on line %d
 
 Fatal error: Uncaught Error: Cannot assign by reference to overloaded object in %s:%d

Zend/tests/lazy_objects/gh20875_proxy_get_no_init.phpt

@@ -0,0 +1,23 @@
+--TEST--
+GH-20875 (Lazy proxy should not initialize when __get handles dynamic property access)
+--FILE--
+<?php
+
+class Foo {
+    public $_;
+
+    public function &__get($name) {
+        echo "__get\n";
+        return $name;
+    }
+}
+
+$proxy = (new ReflectionClass(Foo::class))->newLazyProxy(function () {
+    echo "init\n";
+    return new Foo();
+});
+$x = &$proxy->x;
+
+?>
+--EXPECT--
+__get

Zend/zend_object_handlers.c

@@ -1459,28 +1459,27 @@ ZEND_API zval *zend_std_get_property_ptr_ptr(zend_object *zobj, zend_string *nam
 				return retval;
 		    }
 		}
-		if (UNEXPECTED(zend_lazy_object_must_init(zobj))) {
-			bool guarded = zobj->ce->__get
-				&& (*zend_get_property_guard(zobj, name) & IN_GET);
-			zend_object *instance = zend_lazy_object_init(zobj);
-			if (!instance) {
-				return &EG(error_zval);
-			}
+		if (EXPECTED(!zobj->ce->__get) ||
+		    UNEXPECTED((*zend_get_property_guard(zobj, name)) & IN_GET)) {
+			if (UNEXPECTED(zend_lazy_object_must_init(zobj))) {
+				bool guarded = (zobj->ce->__get != NULL);
+				zend_object *instance = zend_lazy_object_init(zobj);
+				if (!instance) {
+					return &EG(error_zval);
+				}
 
-			if (guarded && (instance->ce->ce_flags & ZEND_ACC_USE_GUARDS)) {
-				uint32_t *guard = zend_get_property_guard(instance, name);
-				if (!(*guard & IN_GET)) {
-					(*guard) |= IN_GET;
-					retval = zend_std_get_property_ptr_ptr(instance, name, type, cache_slot);
-					(*guard) &= ~IN_GET;
-					return retval;
+				if (guarded && (instance->ce->ce_flags & ZEND_ACC_USE_GUARDS)) {
+					uint32_t *guard = zend_get_property_guard(instance, name);
+					if (!(*guard & IN_GET)) {
+						(*guard) |= IN_GET;
+						retval = zend_std_get_property_ptr_ptr(instance, name, type, cache_slot);
+						(*guard) &= ~IN_GET;
+						return retval;
+					}
 				}
-			}
 
-			return zend_std_get_property_ptr_ptr(instance, name, type, cache_slot);
-		}
-		if (EXPECTED(!zobj->ce->__get) ||
-		    UNEXPECTED((*zend_get_property_guard(zobj, name)) & IN_GET)) {
+				return zend_std_get_property_ptr_ptr(instance, name, type, cache_slot);
+			}
 			if (UNEXPECTED(zobj->ce->ce_flags & ZEND_ACC_NO_DYNAMIC_PROPERTIES)) {
 				zend_forbidden_dynamic_property(zobj->ce, name);
 				return &EG(error_zval);