[6.x] Fix Comb search index delete() rewriting JSON when ref absent

src/Search/Comb/Index.php

@@ -94,7 +94,13 @@ public function delete($document)
             return;
         }
 
-        $data->forget($document->getSearchReference());
+        $ref = $document->getSearchReference();
+
+        if (! $data->has($ref)) {
+            return;
+        }
+
+        $data->forget($ref);
 
         $this->save($data);
     }

tests/Search/CombIndexTest.php

@@ -4,15 +4,21 @@
 
 use Illuminate\Contracts\Filesystem\Filesystem;
 use Mockery;
+use PHPUnit\Framework\Attributes\Test;
+use Statamic\Contracts\Search\Searchable;
 use Statamic\Search\Comb\Index;
 use Tests\TestCase;
 
 class CombIndexTest extends TestCase
 {
-    use IndexTests;
+    use IndexTests {
+        tearDown as protected indexTestsTearDown;
+    }
 
     private $fs;
 
+    private ?string $tmpDir = null;
+
     public function setUp(): void
     {
         parent::setUp();
@@ -22,6 +28,18 @@ public function setUp(): void
         $this->instance('filesystem', $this->fs);
     }
 
+    public function tearDown(): void
+    {
+        if ($this->tmpDir && is_dir($this->tmpDir)) {
+            foreach (glob($this->tmpDir.'/*') as $file) {
+                @unlink($file);
+            }
+            @rmdir($this->tmpDir);
+        }
+
+        $this->indexTestsTearDown();
+    }
+
     protected function beforeSearched()
     {
         $this->fs
@@ -39,4 +57,70 @@ public function getIndexClass()
     {
         return Index::class;
     }
+
+    #[Test]
+    public function delete_does_not_rewrite_the_index_when_the_reference_is_absent()
+    {
+        $path = $this->createIndexFile(['entry::a' => ['title' => 'Foo']]);
+
+        $oldMtime = time() - 3600;
+        touch($path, $oldMtime);
+        clearstatcache();
+
+        $index = $this->getIndex('test', ['path' => $this->tmpDir], null);
+
+        $document = Mockery::mock(Searchable::class);
+        $document->shouldReceive('getSearchReference')->andReturn('entry::missing');
+
+        $index->delete($document);
+
+        clearstatcache();
+        $this->assertSame(
+            $oldMtime,
+            filemtime($path),
+            'Comb\Index::delete() rewrote the index file even though the reference was not present.'
+        );
+    }
+
+    #[Test]
+    public function delete_rewrites_the_index_when_the_reference_is_present()
+    {
+        $path = $this->createIndexFile([
+            'entry::a' => ['title' => 'Foo'],
+            'entry::b' => ['title' => 'Bar'],
+        ]);
+
+        $oldMtime = time() - 3600;
+        touch($path, $oldMtime);
+        clearstatcache();
+
+        $index = $this->getIndex('test', ['path' => $this->tmpDir], null);
+
+        $document = Mockery::mock(Searchable::class);
+        $document->shouldReceive('getSearchReference')->andReturn('entry::a');
+
+        $index->delete($document);
+
+        clearstatcache();
+        $this->assertGreaterThan(
+            $oldMtime,
+            filemtime($path),
+            'Comb\Index::delete() did not rewrite the index file even though the reference was present.'
+        );
+
+        $this->assertSame(
+            ['entry::b' => ['title' => 'Bar']],
+            json_decode(file_get_contents($path), true)
+        );
+    }
+
+    private function createIndexFile(array $data): string
+    {
+        $this->tmpDir = sys_get_temp_dir().'/statamic_comb_test_'.uniqid();
+        mkdir($this->tmpDir, 0777, true);
+        $path = $this->tmpDir.'/test.json';
+        file_put_contents($path, json_encode($data));
+
+        return $path;
+    }
 }