Fix For Redacting Readonly Properties

src/RedactSensitiveProcessor.php

@@ -106,7 +106,13 @@ private function traverseArr(array $arr, array $keys): array
 
     private function traverseObj(object $obj, array $keys): object
     {
-        foreach (get_object_vars($obj) as $key => $value) {
+        $vars = get_object_vars($obj);
+        if ($this->containsReadOnlyProperties($obj)) {
+            // create a new object so that redacted copies of readonly variables
+            // can be stored on it
+            $obj = new \stdClass();
+        }
+        foreach ($vars as $key => $value) {
             if (is_scalar($value)) {
                 if (array_key_exists($key, $keys)) {
                     $obj->{$key} = $this->redact((string) $value, $keys[$key]);
@@ -123,4 +129,20 @@ private function traverseObj(object $obj, array $keys): object
 
         return $obj;
     }
+
+    /**
+     * Determines if an object has readonly properties.
+     * @param object $object
+     * @return bool
+     */
+    private function containsReadOnlyProperties(object $object): bool
+    {
+        $reflection = new \ReflectionObject($object);
+        foreach ($reflection->getProperties() as $property) {
+            if ($property->isReadOnly()) {
+                return true;
+            }
+        }
+        return false;
+    }
 }

tests/RedactSensitiveTest.php

@@ -165,3 +165,58 @@
     $record = $this->getRecord(context: [0 => ['good' => 'value'], 1 => ['test' => 'foobar']]);
     expect($processor($record)->context)->toBe([0 => ['good' => 'value'], 1 => ['test' => 'foo***']]);
 });
+
+it('creates copies of objects with readonly properties and redacts them', function (): void {
+    $sensitive_keys = ['test' => 0];
+    $processor = new RedactSensitiveProcessor($sensitive_keys);
+
+    $readonly_properties_object = new class {
+        public function __construct(
+            public readonly string $test = 'foobar',
+        ) {}
+    };
+
+    $record = $this->getRecord(context: ['foo' => $readonly_properties_object]);
+    expect($processor($record)->context['foo']->test)->toBe('******');
+});
+
+it('can redact readonly properties on custom object instances', function (): void {
+    $sensitive_keys = ['test' => 0];
+    $processor = new RedactSensitiveProcessor($sensitive_keys);
+
+    class Foo {
+        public function __construct(
+            public readonly string $test = 'foobar',
+        ) {}
+    }
+    $f = new Foo;
+    $record = $this->getRecord(context: ['foo' => $f]);
+    expect($processor($record)->context['foo']->test)
+        ->toBe('******')
+        ->and($f->test)
+        ->toBe('foobar');
+});
+
+it('can redact readonly properties on custom nested objects', function (): void {
+    $sensitive_keys = ['test' => 0];
+    $processor = new RedactSensitiveProcessor($sensitive_keys);
+
+    class Bar {
+        public function __construct(
+            public readonly object $baz = new Baz
+        ) {}
+    }
+
+    class Baz {
+        public function __construct(
+            public readonly string $test = 'foobar',
+        ) {}
+    }
+
+    $f = new Bar;
+    $record = $this->getRecord(context: ['foo' => $f]);
+    expect($processor($record)->context['foo']->baz->test)
+        ->toBe('******')
+        ->and($f->baz->test)
+        ->toBe('foobar');
+});