BatchBuilder included files fails

Thanks @John Cook!

1. +++ b/core/lib/Drupal/Core/Batch/BatchBuilder.php
   @@ -205,12 +205,18 @@ public function setErrorMessage($message) {
   diff --git a/core/modules/system/tests/fixtures/batch/batch_test_callback_in_file.php b/core/modules/system/tests/fixtures/batch/batch_test_callback_in_file.php
   
   +++ b/core/tests/Drupal/Tests/Core/Batch/BatchBuilderTest.php
   @@ -113,11 +113,12 @@ public function testSetErrorMessage() {
   +    $filename = './modules/system/tests/fixtures/batch/batch_test_callback_in_file.php';
   

   An existed callbacks file could be reused, instead of adding a new one.

2. +++ b/core/tests/Drupal/Tests/Core/Batch/BatchBuilderTest.php
   @@ -113,11 +113,12 @@ public function testSetErrorMessage() {
      public function testSetFile() {
   ...
        $batch = (new BatchBuilder())
   ...
   +      ->setFile($filename)
          ->toArray();
    
   -    $this->assertEquals('filename.php', $batch['file']);
   +    $this->assertEquals( $filename, $batch['file']);
   

   This test does not cover that callbacks in the file are callables.

3. +++ b/core/tests/Drupal/Tests/Core/Batch/BatchBuilderTest.php
   @@ -233,6 +234,17 @@ public function testAddOperation() {
   +    $filename = './modules/system/tests/fixtures/batch/batch_test_callback_in_file.php';
   +    $batch_builder = new BatchBuilder();
   ...
   +    ], $batch['operations']);
   

   The test here is unnecessary to me. which could be a part of ::testSetFile()

4. Tagging "Bug Smash Initiative"

@jungle, I have reviewed the patch in comment #11 for file 3028621-11.patch.
Using the existing batch_test.callbacks.inc make sense. Verified the code in testSetFile() function it LGTM.

Marking it as RTBC.

Nit:

public function testSetFile() {
+    $filename = __DIR__ . '/../../../../../../core/modules/system/tests/modules/batch_test/batch_test.callbacks.inc';

You should use dirname(__DIR__, 6) here.

Thanks, @pratik_kamble and @kim.pepper for reviewing!

Addressing #16.

Self review:

+++ b/core/tests/Drupal/Tests/Core/Batch/BatchBuilderTest.php
@@ -113,7 +113,7 @@ public function testSetErrorMessage() {
+    $filename = dirname(__DIR__, 6) .  '/core/modules/system/tests/modules/batch_test/batch_test.callbacks.inc';
     $this->assertIsNotCallable('_batch_test_callback_1');

One redundant whitespace, fixing.

BTW, filed an issue for similar nitpick with #16

Looked into this for my curiosity.

This was only causing issues from the callable type-hint on the BatchBuilder::addOperation and ::setFinishCallback.

The added include_once is in order for those type-hints to resolve.

The actual loading of the file for the sake of processing the batch happens in _batch_process and _batch_finished

Committed ad50981 and pushed to 9.1.x. Thanks!

Cherry-picked to 9.0.x

Queued an 8.9.x test-run and flagging this for [backport]

#18 passes on 8.9.x.

As this is a bug and there is little disruption, cherry-picked to 8.9.x