refactor: addressed #18757 (comment)

Author: NickSdot

Zend/tests/property_hooks/readonly_property_backed_in_abstract.phpt

@@ -0,0 +1,41 @@
+--TEST--
+Backed readonly property with hooks in abstract class
+--FILE--
+<?php
+abstract class Test {
+
+    public readonly int $prop {
+        get => $this->prop;
+        set => $value;
+    }
+
+    public function __construct(int $v) {
+        $this->prop = $v;
+    }
+
+    public function set(int $v) {
+        $this->prop = $v;
+    }
+}
+
+class Child extends Test {}
+
+$ch = new Child(42);
+var_dump($ch->prop);
+try {
+    $ch->set(43);
+} catch (Error $e) {
+    echo $e::class, ': ', $e->getMessage(), PHP_EOL;
+}
+try {
+    $ch->prop = 43;
+} catch (Error $e) {
+    echo $e::class, ': ', $e->getMessage(), PHP_EOL;
+}
+var_dump($ch->prop);
+?>
+--EXPECT--
+int(42)
+Error: Cannot modify readonly property Test::$prop
+Error: Cannot modify protected(set) readonly property Test::$prop from global scope
+int(42)

Zend/tests/property_hooks/readonly_property_virtual_in_abstract.phpt

@@ -1,5 +1,5 @@
 --TEST--
-Hooked properties in abstract classes cannot be readonly
+Virtual readonly property in abstract class triggers non-abstract body error
 --FILE--
 <?php
 
@@ -8,4 +8,4 @@ abstract class Test {
 }
 ?>
 --EXPECTF--
-Fatal error: Hooked properties in abstract classes cannot be declared readonly in %s on line %d
+Fatal error: Non-abstract property hook must have a body in %s on line %d

Zend/tests/property_hooks/readonly_property_virtual_invalid_in_abstract.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Property hook cannot be both abstract and readonly
+--FILE--
+<?php
+abstract class Test {
+    abstract public readonly int $prop { get; }
+}
+?>
+--EXPECTF--
+Fatal error: Abstract hooked properties cannot be declared readonly in %s on line %d

Zend/zend_compile.c

@@ -8497,20 +8497,6 @@ static void zend_compile_property_hooks(
 {
 	zend_class_entry *ce = CG(active_class_entry);
 
-	/* Allow hooks on backed readonly properties only. */
-	if ((prop_info->flags & (ZEND_ACC_READONLY|ZEND_ACC_VIRTUAL)) == (ZEND_ACC_READONLY|ZEND_ACC_VIRTUAL)) {
-
-		if (ce->ce_flags & ZEND_ACC_INTERFACE) {
-			zend_error_noreturn(E_COMPILE_ERROR, "Interface properties cannot be declared readonly");
-		}
-
-		if (ce->ce_flags & (ZEND_ACC_IMPLICIT_ABSTRACT_CLASS|ZEND_ACC_EXPLICIT_ABSTRACT_CLASS)) {
-			zend_error_noreturn(E_COMPILE_ERROR, "Hooked properties in abstract classes cannot be declared readonly");
-		}
-
-		zend_error_noreturn(E_COMPILE_ERROR, "Hooked virtual properties cannot be declared readonly");
-	}
-
 	if (hooks->children == 0) {
 		zend_error_noreturn(E_COMPILE_ERROR, "Property hook list must not be empty");
 	}
@@ -8666,6 +8652,20 @@ static void zend_compile_property_hooks(
 		}
 	}
 
+	/* Allow hooks on backed readonly properties only. */
+	if ((prop_info->flags & (ZEND_ACC_READONLY|ZEND_ACC_VIRTUAL)) == (ZEND_ACC_READONLY|ZEND_ACC_VIRTUAL)) {
+
+		if (ce->ce_flags & ZEND_ACC_INTERFACE) {
+			zend_error_noreturn(E_COMPILE_ERROR, "Interface properties cannot be declared readonly");
+		}
+
+		if (ce->ce_flags & (ZEND_ACC_IMPLICIT_ABSTRACT_CLASS|ZEND_ACC_EXPLICIT_ABSTRACT_CLASS)) {
+			zend_error_noreturn(E_COMPILE_ERROR, "Abstract hooked properties cannot be declared readonly");
+		}
+
+		zend_error_noreturn(E_COMPILE_ERROR, "Hooked virtual properties cannot be declared readonly");
+	}
+
 	ce->num_hooked_props++;
 
 	/* See zend_link_hooked_object_iter(). */