[BUGFIX] Preserve traversable entries in ForViewHelper

Materialize traversables as key-value pairs when reverse iteration or
iteration metadata requires looking ahead. This keeps duplicate yielded
keys intact and allows iteration totals to work for non-countable
traversables.

Add coverage for non-countable traversables, generators, duplicate keys,
and reverse rendering.

Author: Kanti

src/ViewHelpers/ForViewHelper.php

@@ -99,21 +99,39 @@ public function render(): string
         if (is_object($this->arguments['each']) && !$this->arguments['each'] instanceof \Traversable) {
             throw new InvalidArgumentValueException('ForViewHelper only supports arrays and objects implementing \Traversable interface', 1248728393);
         }
+        $items = null;
         if ($this->arguments['reverse'] === true) {
-            $this->arguments['each'] = array_reverse(iterator_to_array($this->arguments['each']), true);
+            if (is_array($this->arguments['each'])) {
+                $this->arguments['each'] = array_reverse($this->arguments['each'], true);
+            } else {
+                $items = [];
+                foreach ($this->arguments['each'] as $keyValue => $singleElement) {
+                    $items[] = [$keyValue, $singleElement];
+                }
+                $items = array_reverse($items);
+            }
         }
         if (isset($this->arguments['iteration'])) {
+            if ($items === null && !is_countable($this->arguments['each'])) {
+                $items = [];
+                foreach ($this->arguments['each'] as $keyValue => $singleElement) {
+                    $items[] = [$keyValue, $singleElement];
+                }
+            }
             $iterationData = [
                 'index' => 0,
                 'cycle' => 1,
-                'total' => count($this->arguments['each']),
+                'total' => count($items ?? $this->arguments['each']),
             ];
         }
         $globalVariableProvider = $this->renderingContext->getVariableProvider();
         $localVariableProvider = new StandardVariableProvider();
         $this->renderingContext->setVariableProvider(new ScopedVariableProvider($globalVariableProvider, $localVariableProvider));
         $output = '';
-        foreach ($this->arguments['each'] as $keyValue => $singleElement) {
+        foreach ($items ?? $this->arguments['each'] as $keyValue => $singleElement) {
+            if ($items !== null) {
+                [$keyValue, $singleElement] = $singleElement;
+            }
             $localVariableProvider->add($this->arguments['as'], $singleElement);
             if (isset($this->arguments['key'])) {
                 $localVariableProvider->add($this->arguments['key'], $keyValue);

tests/Functional/ViewHelpers/ForViewHelperTest.php

@@ -107,6 +107,57 @@ public static function renderDataProvider(): \Generator
             . '</ul>',
         ];
 
+        $value = new class () implements \IteratorAggregate {
+            public function getIterator(): \Traversable
+            {
+                return new \ArrayIterator([
+                    'first' => 'foo',
+                    'second' => 'bar',
+                ]);
+            }
+        };
+        yield 'iterator total works for non countable traversable' => [
+            '<f:for each="{value}" as="item" iteration="iterator">{item}: {iterator.total}, </f:for>',
+            ['value' => $value],
+            'foo: 2, bar: 2, ',
+        ];
+
+        yield 'iterator total works for generator' => [
+            '<f:for each="{value}" as="item" iteration="iterator">{item}: {iterator.total}, </f:for>',
+            static function () {
+                $value = (static function (): \Generator {
+                    yield 'first' => 'foo';
+                    yield 'second' => 'bar';
+                })();
+                return ['value' => $value];
+            },
+            'foo: 2, bar: 2, ',
+        ];
+
+        yield 'iterator preserves duplicate keys from generator' => [
+            '<f:for each="{value}" as="item" key="key" iteration="iterator">{key}: {item} / {iterator.total}, </f:for>',
+            static function () {
+                $value = (static function (): \Generator {
+                    yield 'duplicate' => 'foo';
+                    yield 'duplicate' => 'bar';
+                })();
+                return ['value' => $value];
+            },
+            'duplicate: foo / 2, duplicate: bar / 2, ',
+        ];
+
+        yield 'reverse preserves duplicate keys from generator' => [
+            '<f:for each="{value}" as="item" key="key" reverse="true">{key}: {item}, </f:for>',
+            static function () {
+                $value = (static function (): \Generator {
+                    yield 'duplicate' => 'foo';
+                    yield 'duplicate' => 'bar';
+                })();
+                return ['value' => $value];
+            },
+            'duplicate: bar, duplicate: foo, ',
+        ];
+
         $value = ['item'];
         yield 'iterator not available if not requested' => [
             '<f:for each="{value}" as="item">Total: {iterator.total}</f:for>',
@@ -200,16 +251,16 @@ public static function renderDataProvider(): \Generator
 
     #[DataProvider('renderDataProvider')]
     #[Test]
-    public function render(string $template, array $variables, string $expected): void
+    public function render(string $template, array|callable $variables, string $expected): void
     {
         $view = new TemplateView();
-        $view->assignMultiple($variables);
+        $view->assignMultiple(is_callable($variables) ? $variables() : $variables);
         $view->getRenderingContext()->setCache(self::$cache);
         $view->getRenderingContext()->getTemplatePaths()->setTemplateSource($template);
         self::assertSame($expected, $view->render());
 
         $view = new TemplateView();
-        $view->assignMultiple($variables);
+        $view->assignMultiple(is_callable($variables) ? $variables() : $variables);
         $view->getRenderingContext()->setCache(self::$cache);
         $view->getRenderingContext()->getTemplatePaths()->setTemplateSource($template);
         self::assertSame($expected, $view->render());