Basic Extension Dependency Support (#2188)

- Don't enable an extension if its dependencies are not enabled
- Don't disable an extension if its dependencies are not disabled

src/Extension/Exception/DependentExtensionsException.php

@@ -0,0 +1,47 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extension\Exception;
+
+use Exception;
+use Flarum\Extension\Extension;
+
+/**
+ * This exception is thrown when someone attempts to disable an extension
+ * that other enabled extensions depend on.
+ */
+class DependentExtensionsException extends Exception
+{
+    public $extension;
+    public $dependent_extensions;
+
+    /**
+     * @param $extension: The extension we are attempting to disable.
+     * @param $dependent_extensions: Enabled Flarum extensions that depend on this extension.
+     */
+    public function __construct(Extension $extension, array $dependent_extensions)
+    {
+        $this->extension = $extension;
+        $this->dependent_extensions = $dependent_extensions;
+
+        parent::__construct($extension->getId().' could not be disabled, because it is a dependency of: '.implode(', ', $this->getDependentExtensionIds()));
+    }
+
+    /**
+     * Get array of IDs for extensions that depend on this extension.
+     *
+     * @return array
+     */
+    public function getDependentExtensionIds()
+    {
+        return array_map(function (Extension $extension) {
+            return $extension->getId();
+        }, $this->dependent_extensions);
+    }
+}

src/Extension/Exception/DependentExtensionsExceptionHandler.php

@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extension\Exception;
+
+use Flarum\Foundation\ErrorHandling\HandledError;
+
+class DependentExtensionsExceptionHandler
+{
+    public function handle(DependentExtensionsException $e): HandledError
+    {
+        return (new HandledError(
+            $e,
+            'dependent_extensions',
+            409
+        ))->withDetails($this->errorDetails($e));
+    }
+
+    protected function errorDetails(DependentExtensionsException $e): array
+    {
+        return [
+            [
+                'extension' => $e->extension->getId(),
+                'extensions' => $e->getDependentExtensionIds(),
+            ]
+        ];
+    }
+}

src/Extension/Exception/MissingDependenciesException.php

@@ -0,0 +1,47 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extension\Exception;
+
+use Exception;
+use Flarum\Extension\Extension;
+
+/**
+ * This exception is thrown when someone attempts to enable an extension
+ * whose Flarum extension dependencies are not all enabled.
+ */
+class MissingDependenciesException extends Exception
+{
+    public $extension;
+    public $missing_dependencies;
+
+    /**
+     * @param $extension: The extension we are attempting to enable.
+     * @param $missing_dependencies: Extensions that this extension depends on, and are not enabled.
+     */
+    public function __construct(Extension $extension, array $missing_dependencies = null)
+    {
+        $this->extension = $extension;
+        $this->missing_dependencies = $missing_dependencies;
+
+        parent::__construct($extension->getId().' could not be enabled, because it depends on: '.implode(', ', $this->getMissingDependencyIds()));
+    }
+
+    /**
+     * Get array of IDs for missing (disabled) extensions that this extension depends on.
+     *
+     * @return array
+     */
+    public function getMissingDependencyIds()
+    {
+        return array_map(function (Extension $extension) {
+            return $extension->getId();
+        }, $this->missing_dependencies);
+    }
+}

src/Extension/Exception/MissingDependenciesExceptionHandler.php

@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extension\Exception;
+
+use Flarum\Foundation\ErrorHandling\HandledError;
+
+class MissingDependenciesExceptionHandler
+{
+    public function handle(MissingDependenciesException $e): HandledError
+    {
+        return (new HandledError(
+            $e,
+            'missing_dependencies',
+            409
+        ))->withDetails($this->errorDetails($e));
+    }
+
+    protected function errorDetails(MissingDependenciesException $e): array
+    {
+        return [
+            [
+                'extension' => $e->extension->getId(),
+                'extensions' => $e->getMissingDependencyIds(),
+            ]
+        ];
+    }
+}