fix(em): prevent use if missing php functions

extensions/package-manager/extend.php

@@ -46,6 +46,11 @@ return [
                 && is_writable($paths->base.'/composer.lock');
 
             $document->payload['flarum-extension-manager.using_sync_queue'] = resolve(Queue::class) instanceof SyncQueue;
+
+            $document->payload['flarum-extension-manager.missing_functions'] = array_values(array_filter(
+                ['proc_open', 'escapeshellarg'],
+                fn (string $function): bool => ! function_exists($function)
+            ));
         }),
 
     new Extend\Locales(__DIR__.'/locale'),

extensions/package-manager/js/src/admin/components/ControlSection.tsx

@@ -1,6 +1,4 @@
-import app from 'flarum/admin/app';
 import Component from 'flarum/common/Component';
-import Alert from 'flarum/common/components/Alert';
 import { ComponentAttrs } from 'flarum/common/Component';
 
 import Installer from './Installer';
@@ -17,18 +15,10 @@ export default class ControlSection extends Component<ComponentAttrs> {
     return (
       <div className="ExtensionPage-settings ExtensionManager-controlSection">
         <div className="container">
-          {app.data['flarum-extension-manager.writable_dirs'] ? (
           <Form>
             <Installer />
             <Updater />
           </Form>
-          ) : (
-            <div className="Form-group">
-              <Alert type="warning" dismissible={false}>
-                {app.translator.trans('flarum-extension-manager.admin.file_permissions')}
-              </Alert>
-            </div>
-          )}
         </div>
       </div>
     );

extensions/package-manager/js/src/admin/components/SettingsPage.tsx

@@ -8,6 +8,7 @@ import ControlSection from './ControlSection';
 import ConfigureComposer from './ConfigureComposer';
 import ConfigureAuth from './ConfigureAuth';
 import DiscoverSection from './DiscoverSection';
+import Alert from 'flarum/common/components/Alert';
 
 export default class SettingsPage extends ExtensionPage {
   content() {
@@ -43,9 +44,33 @@ export default class SettingsPage extends ExtensionPage {
   sections(vnode: Mithril.VnodeDOM<ExtensionPageAttrs, this>): ItemList<unknown> {
     const items = super.sections(vnode);
 
+    const writableDirs = app.data['flarum-extension-manager.writable_dirs'];
+    const missingFunctions = app.data['flarum-extension-manager.missing_functions'] as string[] | undefined;
+    const usable = writableDirs && (!missingFunctions || missingFunctions.length === 0);
+
+    if (usable) {
       items.add('discover', <DiscoverSection />, 15);
 
       items.add('control', <ControlSection />, 10);
+    } else {
+      items.add(
+        'warning',
+        <div className="ExtensionPage-settings">
+          <div className="container">
+            <div className="Form-group">
+              <Alert type="error" dismissible={false}>
+                {!app.data['flarum-extension-manager.writable_dirs']
+                  ? app.translator.trans('flarum-extension-manager.admin.file_permissions')
+                  : app.translator.trans('flarum-extension-manager.admin.required_php_functions', {
+                      functions: (app.data['flarum-extension-manager.missing_functions'] as string[]).join(', '),
+                    })}
+              </Alert>
+            </div>
+          </div>
+        </div>,
+        10
+      );
+    }
 
     items.setPriority('content', 8);
 

extensions/package-manager/locale/en.yml

@@ -99,6 +99,10 @@ flarum-extension-manager:
     minor_update_confirmation:
       content: This will also update any other extensions/packages with available updates.
 
+    required_php_functions: >
+      The extension manager requires the following PHP functions to be enabled: <code>{functions}</code>.
+      If you do not have access to the PHP configuration, please contact your hosting provider.
+
     sections:
       discover:
         description: Add new features and integrations to your Flarum forum with extensions.