Add recoverable review diff service

config/services.php

@@ -41,6 +41,7 @@
 use DR\Review\Service\Git\GitRepositoryService;
 use DR\Review\Service\Git\Review\ReviewDiffService\CacheableReviewDiffService;
 use DR\Review\Service\Git\Review\ReviewDiffService\LockableReviewDiffService;
+use DR\Review\Service\Git\Review\ReviewDiffService\RecoverableReviewDiffService;
 use DR\Review\Service\Git\Review\ReviewDiffService\ReviewDiffService;
 use DR\Review\Service\Git\Review\ReviewDiffService\ReviewDiffServiceInterface;
 use DR\Review\Service\Git\Review\Strategy\BasicCherryPickStrategy;
@@ -191,7 +192,8 @@
     $services->set(HesitantCherryPickStrategy::class)->tag('review_diff_strategy', ['priority' => 10]);
     $services->set('review.diff.service', ReviewDiffService::class)->arg('$reviewDiffStrategies', tagged_iterator('review_diff_strategy'));
 
-    $services->set('lock.review.diff.service', LockableReviewDiffService::class)->arg('$diffService', service('review.diff.service'));
+    $services->set('recoverable.review.diff.service', RecoverableReviewDiffService::class)->arg('$diffService', service('review.diff.service'));
+    $services->set('lock.review.diff.service', LockableReviewDiffService::class)->arg('$diffService', service('recoverable.review.diff.service'));
     $services->set(ReviewDiffServiceInterface::class, CacheableReviewDiffService::class)->arg('$diffService', service('lock.review.diff.service'));
     $services->set(ReviewRouter::class)->decorate('router')->args([service('.inner')]);
     $services->set(CodeReviewFileService::class)->arg('$revisionCache', service(CacheInterface::class . ' $revisionCache'));

src/Service/Git/Review/ReviewDiffService/RecoverableReviewDiffService.php

@@ -0,0 +1,48 @@
+<?php
+declare(strict_types=1);
+
+namespace DR\Review\Service\Git\Review\ReviewDiffService;
+
+use DR\Review\Entity\Repository\Repository;
+use DR\Review\Entity\Review\CodeReview;
+use DR\Review\Service\Git\Review\FileDiffOptions;
+use Psr\Log\LoggerAwareInterface;
+use Psr\Log\LoggerAwareTrait;
+use Symfony\Component\Process\Exception\ProcessFailedException;
+
+class RecoverableReviewDiffService implements ReviewDiffServiceInterface, LoggerAwareInterface
+{
+    use LoggerAwareTrait;
+
+    public function __construct(private readonly ReviewDiffServiceInterface $diffService)
+    {
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function getDiffForRevisions(Repository $repository, array $revisions, ?FileDiffOptions $options = null): array
+    {
+        return $this->diffService->getDiffForRevisions($repository, $revisions, $options);
+    }
+
+    /**
+     * The target branch of the review might be stale, try to reset it to the main branch if the diff fails.
+     * @inheritDoc
+     */
+    public function getDiffForBranch(CodeReview $review, array $revisions, string $branchName, ?FileDiffOptions $options = null): array
+    {
+        try {
+            return $this->diffService->getDiffForBranch($review, $revisions, $branchName, $options);
+        } catch (ProcessFailedException $exception) {
+            if ($review->getTargetBranch() === $review->getRepository()->getMainBranchName()) {
+                throw $exception;
+            }
+
+            $this->logger?->notice('Failed to get diff for branch, trying to reset target branch', ['exception' => $exception]);
+            $review->setTargetBranch($review->getRepository()->getMainBranchName());
+        }
+
+        return $this->diffService->getDiffForBranch($review, $revisions, $branchName, $options);
+    }
+}

tests/Unit/Service/Git/Review/ReviewDiffService/RecoverableReviewDiffServiceTest.php

@@ -0,0 +1,92 @@
+<?php
+declare(strict_types=1);
+
+namespace DR\Review\Tests\Unit\Service\Git\Review\ReviewDiffService;
+
+use DR\Review\Entity\Git\Diff\DiffComparePolicy;
+use DR\Review\Entity\Repository\Repository;
+use DR\Review\Entity\Review\CodeReview;
+use DR\Review\Entity\Revision\Revision;
+use DR\Review\Service\Git\Review\FileDiffOptions;
+use DR\Review\Service\Git\Review\ReviewDiffService\RecoverableReviewDiffService;
+use DR\Review\Service\Git\Review\ReviewDiffService\ReviewDiffServiceInterface;
+use DR\Review\Tests\AbstractTestCase;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\MockObject\MockObject;
+use stdClass;
+use Symfony\Component\Process\Exception\ProcessFailedException;
+use Throwable;
+
+#[CoversClass(RecoverableReviewDiffService::class)]
+class RecoverableReviewDiffServiceTest extends AbstractTestCase
+{
+    private ReviewDiffServiceInterface&MockObject $diffService;
+    private RecoverableReviewDiffService          $service;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->diffService = $this->createMock(ReviewDiffServiceInterface::class);
+        $this->service     = new RecoverableReviewDiffService($this->diffService);
+    }
+
+    /**
+     * @throws Throwable
+     */
+    public function testGetDiffForRevisions(): void
+    {
+        $repository = new Repository();
+        $revisions  = [new Revision()];
+        $options    = new FileDiffOptions(5, DiffComparePolicy::ALL);
+
+        $this->diffService->expects(self::once())->method('getDiffForRevisions')->with($repository, $revisions, $options);
+
+        $this->service->getDiffForRevisions($repository, $revisions, $options);
+    }
+
+    /**
+     * @throws Throwable
+     */
+    public function testGetDiffForBranchExpectTwoAttempts(): void
+    {
+        $callCount        = new stdClass();
+        $callCount->count = 0;
+        $repository       = (new Repository())->setMainBranchName('master');
+        $review           = (new CodeReview())->setTargetBranch('foobar')->setRepository($repository);
+        $revisions        = [new Revision()];
+        $options          = new FileDiffOptions(5, DiffComparePolicy::ALL);
+        $branchName       = 'branch';
+
+        $exception = $this->createMock(ProcessFailedException::class);
+
+        $this->diffService->expects(self::exactly(2))->method('getDiffForBranch')
+            ->with($review, $revisions, $branchName, $options)
+            ->willThrowException($exception);
+
+        $this->expectException(ProcessFailedException::class);
+        $this->service->getDiffForBranch($review, $revisions, $branchName, $options);
+    }
+
+    /**
+     * @throws Throwable
+     */
+    public function testGetDiffForBranchExpectOneAttemptOnMasterBranch(): void
+    {
+        $callCount        = new stdClass();
+        $callCount->count = 0;
+        $repository       = (new Repository())->setMainBranchName('master');
+        $review           = (new CodeReview())->setTargetBranch('master')->setRepository($repository);
+        $revisions        = [new Revision()];
+        $options          = new FileDiffOptions(5, DiffComparePolicy::ALL);
+        $branchName       = 'branch';
+
+        $exception = $this->createMock(ProcessFailedException::class);
+
+        $this->diffService->expects(self::once())->method('getDiffForBranch')
+            ->with($review, $revisions, $branchName, $options)
+            ->willThrowException($exception);
+
+        $this->expectException(ProcessFailedException::class);
+        $this->service->getDiffForBranch($review, $revisions, $branchName, $options);
+    }
+}