project-config/sync command, plus apply yawl changes in app/migrate

resolves #3510

CHANGELOG-v3.md

@@ -1,5 +1,13 @@
 # Release Notes for Craft CMS 3.x
 
+## Unreleased
+
+### Added
+- Added a new `project-config/sync` console command. ([#3510](https://github.com/craftcms/cms/issues/3510))
+
+### Changed
+- The `app/migrate` web action now applies pending `project.yaml` changes, if the `useProjectConfigFile` config setting is enabled.
+
 ## 3.1.0-beta.4 - 2018-11-30
 
 ### Changed

src/console/controllers/ProjectConfigController.php

@@ -0,0 +1,46 @@
+<?php
+/**
+ * @link https://craftcms.com/
+ * @copyright Copyright (c) Pixel & Tonic, Inc.
+ * @license https://craftcms.github.io/license/
+ */
+
+namespace craft\console\controllers;
+
+use Craft;
+use craft\helpers\Console;
+use yii\console\Controller;
+use yii\console\ExitCode;
+
+/**
+ * Manages the project config.
+ *
+ * @author Pixel & Tonic, Inc. <[email protected]>
+ * @since 3.1
+ */
+class ProjectConfigController extends Controller
+{
+    /**
+     * Syncs the project config.
+     *
+     * @return int
+     */
+    public function actionSync(): int
+    {
+        if (!Craft::$app->getConfig()->getGeneral()->useProjectConfigFile) {
+            $this->stdout('Craft is not configured to use project.yaml. Please enable the \'useProjectConfigFile\' config setting in config/general.php.' . PHP_EOL, Console::FG_YELLOW);
+            return ExitCode::OK;
+        }
+
+        $this->stdout('Applying changes from project.yaml... ', Console::FG_YELLOW);
+        try {
+            Craft::$app->getProjectConfig()->applyYamlChanges();
+        } catch (\Throwable $e) {
+            $this->stderr('error: ' . $e->getMessage() . PHP_EOL, Console::FG_RED);
+            return ExitCode::UNSPECIFIED_ERROR;
+        }
+
+        $this->stdout('done' . PHP_EOL, Console::FG_GREEN);
+        return ExitCode::OK;
+    }
+}

src/controllers/AppController.php

@@ -114,7 +114,8 @@ public function actionCheckForUpdates(): Response
     }
 
     /**
-     * Creates a DB backup (if configured to do so) and runs any pending Craft, plugin, & content migrations in one go.
+     * Creates a DB backup (if configured to do so), runs any pending Craft,
+     * plugin, & content migrations, and syncs `project.yaml` changes in one go.
      *
      * This action can be used as a post-deploy webhook with site deployment
      * services (like [DeployBot](https://deploybot.com/)) to minimize site
@@ -163,6 +164,11 @@ public function actionMigrate()
             // Run the migrations
             $updatesService->runMigrations($handles);
 
+            // Sync project.yaml?
+            if ($generalConfig->useProjectConfigFile) {
+                Craft::$app->getProjectConfig()->applyYamlChanges();
+            }
+
             $transaction->commit();
         } catch (\Throwable $e) {
             $transaction->rollBack();