Share variables shared via View::share() with Twig templates (#969)

Fixes #630

This allows global variables populated by the View::share('name', 'value') method to be used in Twig templates. The values will only be populated if they have not been specified as a global previously, to prevent overriding system globals such as this.page. It will also allow the pages themselves to still override the values if need be.

modules/cms/classes/Controller.php

@@ -319,6 +319,19 @@ public function runPage($page, $useAjax = true)
             'session'     => App::make('session'),
         ]);
 
+        /*
+         * Add global vars defined by View::share() into Twig, only if they have yet to be specified.
+         */
+        $globalVars = ViewHelper::getGlobalVars();
+        if (!empty($globalVars)) {
+            $existingGlobals = array_keys($this->getTwig()->getGlobals());
+            foreach ($globalVars as $key => $value) {
+                if (!in_array($key, $existingGlobals)) {
+                    $this->getTwig()->addGlobal($key, $value);
+                }
+            }
+        }
+
         /*
          * Check for the presence of validation errors in the session.
          */

modules/cms/tests/classes/CmsObjectQueryTest.php

@@ -84,6 +84,8 @@ public function testLists()
             "no-soft-component-class",
             "optional-full-php-tags",
             "optional-short-php-tags",
+            "shared-variable",
+            "shared-variable-override",
             "throw-php",
             "with-component",
             "with-components",

modules/cms/tests/classes/ControllerTest.php

@@ -3,10 +3,11 @@
 namespace Cms\Tests\Classes;
 
 use Cms;
+use Request;
 use System\Tests\Bootstrap\TestCase;
 use Cms\Classes\Theme;
 use Cms\Classes\Controller;
-use Request;
+use System\Helpers\View;
 use Winter\Storm\Halcyon\Model;
 use Winter\Storm\Support\Facades\Config;
 
@@ -25,6 +26,8 @@ public function setUp(): void
         Model::clearBootedModels();
         Model::flushEventListeners();
 
+        View::clearVarCache();
+
         include_once base_path() . '/modules/system/tests/fixtures/plugins/winter/tester/components/Archive.php';
         include_once base_path() . '/modules/system/tests/fixtures/plugins/winter/tester/components/Post.php';
         include_once base_path() . '/modules/system/tests/fixtures/plugins/winter/tester/components/MainMenu.php';
@@ -682,4 +685,68 @@ public function testMacro()
             $response
         );
     }
+
+    public function testSharedVariable()
+    {
+        $this->app['view']->share('winterStatus', 'Is Awesome');
+
+        $theme = Theme::load('test');
+        $controller = new Controller($theme);
+        $response = $controller->run('/shared-variable')->getContent();
+
+        $this->assertStringContainsString(
+            '<p>Winter Is Awesome</p>',
+            $response
+        );
+
+        $this->assertStringContainsString(
+            '<p>/shared-variable</p>',
+            $response
+        );
+    }
+
+    public function testSharedVariableCannotOverrideSystemGlobals()
+    {
+        $this->app['view']->share('winterStatus', 'Is Awesome');
+
+        // This override should not apply and change the page URL in the fixture template
+        $this->app['view']->share('this', [
+            'page' => [
+                'url' => '/overriden',
+            ],
+        ]);
+
+        $theme = Theme::load('test');
+        $controller = new Controller($theme);
+        $response = $controller->run('/shared-variable')->getContent();
+
+        $this->assertStringContainsString(
+            '<p>Winter Is Awesome</p>',
+            $response
+        );
+
+        $this->assertStringContainsString(
+            '<p>/shared-variable</p>',
+            $response
+        );
+    }
+
+    public function testSharedVariableCanBeOverriddenLocally()
+    {
+        $this->app['view']->share('winterStatus', 'Is Awesome');
+
+        $theme = Theme::load('test');
+        $controller = new Controller($theme);
+        $response = $controller->run('/shared-variable-override')->getContent();
+
+        $this->assertStringContainsString(
+            '<p>Winter Is Coming</p>',
+            $response
+        );
+
+        $this->assertStringContainsString(
+            '<p>/shared-variable-override</p>',
+            $response
+        );
+    }
 }

modules/cms/tests/fixtures/themes/test/pages/shared-variable-override.htm

@@ -0,0 +1,10 @@
+url = '/shared-variable-override'
+==
+<?php
+function onStart() {
+    $this['winterStatus'] = 'Is Coming';
+}
+==
+<p>Winter {{ winterStatus }}</p>
+
+<p>{{ this.page.url }}</p>

modules/cms/tests/fixtures/themes/test/pages/shared-variable.htm

@@ -0,0 +1,5 @@
+url = '/shared-variable'
+==
+<p>Winter {{ winterStatus }}</p>
+
+<p>{{ this.page.url }}</p>

modules/system/helpers/View.php

@@ -37,4 +37,14 @@ public static function getGlobalVars()
 
         return static::$globalVarCache = $vars;
     }
+
+    /**
+     * Clears the static cache for global variables.
+     *
+     * @return void
+     */
+    public static function clearVarCache()
+    {
+        static::$globalVarCache = null;
+    }
 }