Issue #2833462 by alexpott, tim.plunkett, Berdir: hook_requirements($phase =...

Issue #2833462 by alexpott, tim.plunkett, Berdir: hook_requirements($phase = 'install') does not work as expected for experimental modules

core/modules/system/src/Form/ModulesListForm.php

@@ -411,6 +411,7 @@ protected function buildModuleList(FormStateInterface $form_state) {
     foreach (array_keys($modules['install']) as $module) {
       if (!drupal_check_module($module)) {
         unset($modules['install'][$module]);
+        unset($modules['experimental'][$module]);
         foreach (array_keys($data[$module]->required_by) as $dependent) {
           unset($modules['install'][$dependent]);
           unset($modules['dependencies'][$dependent]);

core/modules/system/src/Tests/Module/ExperimentalModuleTest.php

@@ -120,6 +120,14 @@ public function testExperimentalConfirmForm() {
     $this->drupalPostForm(NULL, [], 'Continue');
     $this->assertText('2 modules have been enabled: Experimental Test, Experimental Dependency Test');
 
+    // Try to enable an experimental module that can not be due to
+    // hook_requirements().
+    \Drupal::state()->set('experimental_module_requirements_test_requirements', TRUE);
+    $edit = [];
+    $edit["modules[Core (Experimental)][experimental_module_requirements_test][enable]"] = TRUE;
+    $this->drupalPostForm('admin/modules', $edit, 'Install');
+    $this->assertUrl('admin/modules', [], 'If the module can not be installed we are not taken to the confirm form.');
+    $this->assertText('The Experimental Test Requirements module can not be installed.');
   }
 
 }

core/modules/system/tests/modules/experimental_module_requirements_test/experimental_module_requirements_test.info.yml

+name: 'Experimental Requirements Test'
+type: module
+description: 'Module in the experimental package to test hook_requirements() with an experimental module.'
+package: Core (Experimental)
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/experimental_module_requirements_test/experimental_module_requirements_test.install

+<?php
+
+/**
+ * @file
+ * Experimental Test Requirements module to test hook_requirements().
+ */
+
+/**
+ * Implements hook_requirements().
+ */
+function experimental_module_requirements_test_requirements() {
+  $requirements = [];
+  if (\Drupal::state()->get('experimental_module_requirements_test_requirements', FALSE)) {
+    $requirements['experimental_module_requirements_test_requirements'] = [
+      'severity' => REQUIREMENT_ERROR,
+      'description' => t('The Experimental Test Requirements module can not be installed.'),
+    ];
+  }
+  return $requirements;
+}

core/modules/system/tests/modules/experimental_module_requirements_test/experimental_module_requirements_test.module

+<?php
+
+/**
+ * @file
+ * Experimental Test Requirements module to test hook_requirements().
+ */
+
+/**
+ * Implements hook_help().
+ */
+function experimental_module_requirements_test_help($route_name) {
+  switch ($route_name) {
+    case 'help.page.experimental_module_requirements_test':
+      // Make the help text conform to core standards. See
+      // \Drupal\system\Tests\Module\InstallUninstallTest::assertHelp().
+      return t('The Experimental Requirements Test module is not done yet. It may eat your data, but you can read the <a href=":url">online documentation for the Experimental Requirements Test module</a>.', [':url' => 'http://www.example.com']);
+  }
+}