Fixes showing files changed in JSON formatter

src/ChangesReporting/Output/JsonOutputFormatter.php

@@ -31,19 +31,22 @@ public function report(ProcessResult $processResult, Configuration $configuratio
             ],
         ];
 
-        $fileDiffs = $processResult->getFileDiffs();
+        // We need onlyWithChanges: false to include all file diffs
+        $fileDiffs = $processResult->getFileDiffs(onlyWithChanges: false);
         ksort($fileDiffs);
         foreach ($fileDiffs as $fileDiff) {
             $filePath = $configuration->isReportingWithRealPath()
                 ? ($fileDiff->getAbsoluteFilePath() ?? '')
                 : $fileDiff->getRelativeFilePath()
             ;
 
-            $errorsJson[Bridge::FILE_DIFFS][] = [
-                'file' => $filePath,
-                'diff' => $fileDiff->getDiff(),
-                'applied_rectors' => $fileDiff->getRectorClasses(),
-            ];
+            if ($configuration->shouldShowDiffs() && $fileDiff->getDiff() !== '') {
+                $errorsJson[Bridge::FILE_DIFFS][] = [
+                    'file' => $filePath,
+                    'diff' => $fileDiff->getDiff(),
+                    'applied_rectors' => $fileDiff->getRectorClasses(),
+                ];
+            }
 
             // for Rector CI
             $errorsJson['changed_files'][] = $filePath;

tests/ChangesReporting/Output/Fixtures/without_diffs.json

@@ -0,0 +1,17 @@
+{
+    "totals": {
+        "changed_files": 2,
+        "errors": 1
+    },
+    "changed_files": [
+        "some/file.php",
+        "some/file_foo.php"
+    ],
+    "errors": [
+        {
+            "message": "Some error message",
+            "file": "some/file.php",
+            "line": 1
+        }
+    ]
+}

tests/ChangesReporting/Output/JsonOutputFormatterTest.php

@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ChangesReporting\Output;
+
+use PHPUnit\Framework\TestCase;
+use Rector\ChangesReporting\Output\JsonOutputFormatter;
+use Rector\ChangesReporting\ValueObject\RectorWithLineChange;
+use Rector\Php80\Rector\Identical\StrStartsWithRector;
+use Rector\ValueObject\Configuration;
+use Rector\ValueObject\Error\SystemError;
+use Rector\ValueObject\ProcessResult;
+use Rector\ValueObject\Reporting\FileDiff;
+
+final class JsonOutputFormatterTest extends TestCase
+{
+    private readonly JsonOutputFormatter $jsonOutputFormatter;
+
+    protected function setUp(): void
+    {
+        $this->jsonOutputFormatter = new JsonOutputFormatter();
+
+        parent::setUp();
+    }
+
+    public function testGetName(): void
+    {
+        $this->assertSame('json', $this->jsonOutputFormatter->getName());
+    }
+
+    public function testReportShouldShowNumberOfChangesWithNoDiffs(): void
+    {
+        $expectedOutput = (string) file_get_contents(__DIR__ . '/Fixtures/without_diffs.json');
+        $this->expectOutputString(rtrim($expectedOutput) . PHP_EOL);
+
+        $this->jsonOutputFormatter->report(
+            new ProcessResult(
+                [new SystemError('Some error message', 'some/file.php', 1)],
+                [
+                    new FileDiff(
+                        'some/file.php',
+                        <<<'DIFF'
+                        --- Original
+                        +++ New
+                        @@ -38,5 +39,6 @@
+                        return true;
+                        }
+
+                        DIFF,
+                        'diff console formatted',
+                        [new RectorWithLineChange(StrStartsWithRector::class, 38)]
+                    ),
+                    new FileDiff(
+                        'some/file_foo.php',
+                        '',
+                        '',
+                        [new RectorWithLineChange(StrStartsWithRector::class, 38)]
+                    ),
+                ],
+                2
+            ),
+            new Configuration(showDiffs: false)
+        );
+    }
+}