Issue #3044868 by Pancho: Don't save unvalidated backend configuration if another backend is chosen

src/Form/FillPdfSettingsForm.php

@@ -286,15 +286,29 @@ class FillPdfSettingsForm extends ConfigFormBase {
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
     // Save form values.
-    $this->config('fillpdf.settings')
-      ->set('backend', $form_state->getValue('backend'))
-      ->set('remote_endpoint', $form_state->getValue('remote_endpoint'))
-      ->set('fillpdf_service_api_key', $form_state->getValue('fillpdf_service_api_key'))
-      ->set('remote_protocol', $form_state->getValue('remote_protocol'))
-      ->set('pdftk_path', $form_state->getValue('pdftk_path'))
-      ->set('scheme', $form_state->getValue('scheme'))
-      ->set('local_service_endpoint', $form_state->getValue('local_service_endpoint'))
-      ->save();
+    $values = $form_state->getValues();
+    $config = $this->config('fillpdf.settings');
+
+    $config->set('scheme', $values['scheme'])
+      ->set('backend', $values['backend']);
+
+    switch ($values['backend']) {
+      case 'fillpdf_service':
+        $config->set('remote_endpoint', $values['remote_endpoint'])
+          ->set('fillpdf_service_api_key', $values['fillpdf_service_api_key'])
+          ->set('remote_protocol', $values['remote_protocol']);
+        break;
+
+      case 'local_service':
+        $config->set('local_service_endpoint', $values['local_service_endpoint']);
+        break;
+
+      case 'pdftk':
+        $config->set('pdftk_path', $form_state->getValue('pdftk_path'));
+        break;
+    }
+
+    $config->save();
 
     parent::submitForm($form, $form_state);
   }

tests/src/Functional/FillPdfSettingsFormTest.php

@@ -120,6 +120,30 @@ class FillPdfSettingsFormTest extends BrowserTestBase {
     $this->assertEqual($this->config('fillpdf.settings')->get('scheme'), 'private');
   }
 
+  /**
+   * Tests the backend settings with the 'fillpdf_service' backend.
+   */
+  public function testSettingsFormBackendFillPdfService() {
+    // FillPDF is not yet configured. The settings form is however initialized
+    // with the 'fillpdf_service' backend. Save that configuration.
+    $this->drupalPostForm(Url::fromRoute('fillpdf.settings'), NULL, 'Save configuration');
+
+    // There's currently no validation, so the 'backend' setting should be
+    // both submitted and stored.
+    $this->assertSession()->pageTextContains('The configuration options have been saved.');
+    $this->assertSession()->fieldValueEquals('backend', 'fillpdf_service');
+    $this->assertEqual($this->config('fillpdf.settings')->get('backend'), 'fillpdf_service');
+
+    // Now add an API key and save again.
+    $this->drupalPostForm(NULL, ['fillpdf_service_api_key' => 'Invalid, just playing around.'], 'Save configuration');
+
+    // There's currently no validation, so the obviously invalid
+    // 'fillpdf_service_api_key' should be both submitted and stored.
+    $this->assertSession()->pageTextContains('The configuration options have been saved.');
+    $this->assertSession()->fieldValueEquals('fillpdf_service_api_key', 'Invalid, just playing around.');
+    $this->assertEqual($this->config('fillpdf.settings')->get('fillpdf_service_api_key'), 'Invalid, just playing around.');
+  }
+
   /**
    * Tests the backend settings with the 'pdftk' backend.
    */
@@ -155,12 +179,14 @@ class FillPdfSettingsFormTest extends BrowserTestBase {
     $this->assertSession()->pageTextContainsOnce('plugin for testing');
     $this->assertSession()->pageTextContains('Form-altered pass-through plugin for testing');
 
-    // Try configuring FillPDF with the 'test' backend, yet an invalid value
-    // for the form-altered configuration setting.
+    // Try configuring FillPDF with the 'test' backend, yet with invalid values
+    // for the form-altered 'example_setting' and the unrelated
+    // 'fillpdf_service_api_key'.
     $edit = [
       'scheme' => 'private',
       'backend' => 'test',
       'example_setting' => 'x',
+      'fillpdf_service_api_key' => 'Invalid, just playing around.',
     ];
     $this->drupalPostForm(NULL, $edit, 'Save configuration');
 
@@ -182,10 +208,12 @@ class FillPdfSettingsFormTest extends BrowserTestBase {
     // This time, our custom validation handler passes.
     $this->assertSession()->pageTextNotContains('Not a valid value.');
     $this->assertSession()->pageTextContains('The configuration options have been saved.');
-    // So the new values should be submitted *and* saved this time.
-    foreach ($edit as $field => $value) {
-      $this->assertEqual($this->config('fillpdf.settings')->get($field), $value);
+    // So the new values should be submitted *and* saved this time, except for
+    // the unrelated 'fillpdf_service_api_key' which should be dismissed.
+    $expected = ['fillpdf_service_api_key' => NULL] + $edit;
+    foreach ($expected as $field => $value) {
       $this->assertSession()->fieldValueEquals($field, $value);
+      $this->assertEqual($this->config('fillpdf.settings')->get($field), $value);
     }
   }