Fix keeping data from group child steps

The `Step::keep()` methods now also work when applied to child steps
within a group step.

Author: otsch

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 ### Fixed
 * When providing an empty base selector to an `Html` step (`Html::each('')`, `Html::first('')`, `Html::last('')`), it won't fail with an error, but instead log a warning, that it most likely doesn't make sense.
+* The `Step::keep()` methods now also work when applied to child steps within a group step.
 
 ## [3.4.2] - 2025-03-08
 ### Fixed

src/Steps/Group.php

@@ -28,7 +28,7 @@ final class Group extends BaseStep
      */
     public function invokeStep(Input $input): Generator
     {
-        $combinedOutput = [];
+        $combinedOutput = $combinedKeptData = [];
 
         if ($this->uniqueInput && !$this->inputOrOutputIsUnique($input)) {
             return;
@@ -46,16 +46,23 @@ public function invokeStep(Input $input): Generator
                     }
 
                     if ($this->includeOutput($step)) {
-                        $combinedOutput = $this->addOutputToCombinedOutputs(
+                        $combinedOutput = $this->addToCombinedOutputData(
                             $output->get(),
                             $combinedOutput,
                             $nthOutput,
                         );
                     }
+
+                    // Also transfer data, kept in group child steps, to the kept data of the final group output.
+                    if ($output->keep !== $inputForStepInvocation->keep) {
+                        $keep = $this->getNewlyKeptData($output, $inputForStepInvocation);
+
+                        $combinedKeptData = $this->addToCombinedOutputData($keep, $combinedKeptData, $nthOutput);
+                    }
                 }
             }
 
-            yield from $this->prepareCombinedOutputs($combinedOutput, $input);
+            yield from $this->prepareCombinedOutputs($combinedOutput, $combinedKeptData, $input);
         }
     }
 
@@ -134,31 +141,39 @@ protected function includeOutput(StepInterface $step): bool
      * @param mixed[] $combined
      * @return mixed[]
      */
-    private function addOutputToCombinedOutputs(
-        mixed $output,
-        array $combined,
-        int $nthOutput,
-    ): array {
-        if (is_array($output)) {
-            foreach ($output as $key => $value) {
-                $combined[$nthOutput][$key][] = $value;
+    private function addToCombinedOutputData(mixed $add, array $combined, int $nthElement): array
+    {
+        if (is_array($add)) {
+            foreach ($add as $key => $value) {
+                $combined[$nthElement][$key][] = $value;
             }
         } else {
-            $combined[$nthOutput][][] = $output;
+            $combined[$nthElement][][] = $add;
         }
 
         return $combined;
     }
 
+    /**
+     * @return mixed[]
+     */
+    private function getNewlyKeptData(Output $output, Input $input): array
+    {
+        return array_filter($output->keep, function ($key) use ($input) {
+            return !array_key_exists($key, $input->keep);
+        }, ARRAY_FILTER_USE_KEY);
+    }
+
     /**
      * @param mixed[] $combinedOutputs
+     * @param mixed[] $combinedKeptData
      * @param Input $input
      * @return Generator<Output>
      * @throws Exception
      */
-    private function prepareCombinedOutputs(array $combinedOutputs, Input $input): Generator
+    private function prepareCombinedOutputs(array $combinedOutputs, array $combinedKeptData, Input $input): Generator
     {
-        foreach ($combinedOutputs as $combinedOutput) {
+        foreach ($combinedOutputs as $key => $combinedOutput) {
             if ($this->maxOutputsExceeded()) {
                 break;
             }
@@ -170,6 +185,10 @@ private function prepareCombinedOutputs(array $combinedOutputs, Input $input): G
             if ($this->passesAllFilters($outputData)) {
                 $output = $this->makeOutput($outputData, $input);
 
+                if (array_key_exists($key, $combinedKeptData)) {
+                    $output->keep($this->normalizeCombinedOutputs($combinedKeptData[$key]));
+                }
+
                 if ($this->uniqueOutput !== false && !$this->inputOrOutputIsUnique($output)) {
                     continue;
                 }

tests/Steps/GroupTest.php

@@ -529,6 +529,46 @@ function () {
         ]);
 });
 
+it('keeps data, when keep() is called on child steps', function () {
+    $step1 = helper_getValueReturningStep(['foo' => 'fooValue', 'bar' => 'barValue']);
+
+    $step2 = helper_getValueReturningStep(['baz' => 'bazValue', 'quz' => 'quzValue']);
+
+    $group = (new Group())
+        ->addStep($step1->keep('foo'))
+        ->addStep($step2->keep(['baz', 'quz']));
+
+    $output = helper_invokeStepWithInput($group);
+
+    expect($output)->toHaveCount(1)
+        ->and($output[0]->keep)->toBe([
+            'foo' => 'fooValue',
+            'baz' => 'bazValue',
+            'quz' => 'quzValue',
+        ]);
+});
+
+it('keeps data, when keepAs() is called on child steps', function () {
+    $step1 = helper_getValueReturningStep('fooValue');
+
+    $step2 = helper_getValueReturningStep(['bar' => 'barValue', 'baz' => 'bazValue']);
+
+    $group = (new Group())
+        ->addStep($step1->keepAs('foo'))
+        ->addStep($step2->keepAs('quz'));
+
+    $output = helper_invokeStepWithInput($group);
+
+    expect($output)->toHaveCount(1)
+        ->and($output[0]->keep)->toBe([
+            'foo' => 'fooValue',
+            'quz' => [
+                'bar' => 'barValue',
+                'baz' => 'bazValue',
+            ],
+        ]);
+});
+
 test(
     'when steps yield multiple outputs it combines the first output from first step with first output from second ' .
         'step and so on.',