CMS Twig extension contentFunction() should return bool like partialFunction() (#746)

This allows people to use the `content` function as a conditional to add fallback content if a given content file does not exist.

modules/cms/classes/Controller.php

@@ -1098,10 +1098,11 @@ class Controller
      *
      * @param string $name The content view to load.
      * @param array $parameters Parameter variables to pass to the view.
-     * @throws SystemException If the content cannot be found
-     * @return string
+     * @param bool $throwException Throw an exception if the content file is not found.
+     * @throws SystemException If the content cannot be found, and `$throwException` is true.
+     * @return string|false Content file, or false if `$throwException` is false.
      */
-    public function renderContent($name, $parameters = [])
+    public function renderContent($name, $parameters = [], $throwException = true)
     {
         /**
          * @event cms.page.beforeRenderContent
@@ -1127,7 +1128,11 @@ class Controller
          * Load content from theme
          */
         elseif (($content = Content::loadCached($this->theme, $name)) === null) {
-            throw new SystemException(Lang::get('cms::lang.content.not_found_name', ['name'=>$name]));
+            if ($throwException) {
+                throw new SystemException(Lang::get('cms::lang.content.not_found_name', ['name' => $name]));
+            } else {
+                return false;
+            }
         }
 
         $fileContent = $content->parsedMarkup;

modules/cms/tests/classes/TwigExtensionTest.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Cms\Tests\Classes;
+
+use Cms\Twig\Extension;
+use Cms\Classes\Controller;
+
+use System\Tests\Bootstrap\TestCase;
+use Winter\Storm\Exception\SystemException;
+
+class TwigExtensionTest extends TestCase
+{
+    public function testPartialFunction()
+    {
+        $extension = new Extension;
+        $controller = Controller::getController() ?: new Controller;
+        $extension->setController($controller);
+
+        $this->assertFalse($extension->partialFunction('invalid-partial-file', [], false));
+
+        $this->expectException(SystemException::class);
+        $this->expectExceptionMessageMatches('/is\snot\sfound/');
+        $this->assertFalse($extension->partialFunction('invalid-partial-file', [], true));
+    }
+
+    public function testContentFunction()
+    {
+        $extension = new Extension;
+        $controller = Controller::getController() ?: new Controller;
+        $extension->setController($controller);
+
+        $this->assertFalse($extension->contentFunction('invalid-content-file', [], false));
+
+        $this->expectException(SystemException::class);
+        $this->expectExceptionMessageMatches('/is\snot\sfound/');
+        $this->assertFalse($extension->contentFunction('invalid-content-file', [], true));
+    }
+}

modules/cms/twig/ContentNode.php

@@ -39,6 +39,7 @@ class ContentNode extends TwigNode
             ->write("echo \$this->env->getExtension('Cms\Twig\Extension')->contentFunction(")
             ->subcompile($this->getNode('nodes')->getNode(0))
             ->write(", \$context['__cms_content_params']")
+            ->write(", true")
             ->write(");\n")
         ;
 

modules/cms/twig/Extension.php

@@ -101,7 +101,7 @@ class Extension extends TwigExtension
     /**
      * Renders the requested partial with the provided parameters. Optionally throw an exception if the partial cannot be found
      */
-    public function partialFunction(string $name, array $parameters = [], bool $throwException = false): string
+    public function partialFunction(string $name, array $parameters = [], bool $throwException = false): string|bool
     {
         return $this->controller->renderPartial($name, $parameters, $throwException);
     }
@@ -109,9 +109,9 @@ class Extension extends TwigExtension
     /**
      * Renders the requested content file.
      */
-    public function contentFunction(string $name, array $parameters = []): string
+    public function contentFunction(string $name, array $parameters = [], bool $throwException = false): string|bool
     {
-        return $this->controller->renderContent($name, $parameters);
+        return $this->controller->renderContent($name, $parameters, $throwException);
     }
 
     /**