[TASK] Write cleaner FileWriter JSON output

Since PHP 5.4 it's possible to disable escaping for unicode characters
and slashes, which results in a much cleaner, leaner and most
importantly readable TYPO3 log output.

Releases: master, 9.5
Resolves: #88120
Related: #77274
Change-Id: I5b331e29e0f036d3d95b0f1045c269a28fec6abb
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60431


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Tomas Norre Mikkelsen <tomasnorre@gmail.com>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Frank Naegler <frank.naegler@typo3.org>

typo3/sysext/core/Classes/Log/Writer/FileWriter.php

@@ -154,7 +154,7 @@ class FileWriter extends AbstractWriter
             if (isset($recordData['exception']) && $recordData['exception'] instanceof \Exception) {
                 $recordData['exception'] = (string)$recordData['exception'];
             }
-            $data = '- ' . json_encode($recordData);
+            $data = '- ' . json_encode($recordData, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
         }
 
         $message = sprintf(

typo3/sysext/core/Tests/Unit/Log/Writer/FileWriterTest.php

@@ -152,6 +152,28 @@ class FileWriterTest extends UnitTestCase
         $this->assertEquals($expectedResult, $logFileContents);
     }
 
+    /**
+     * @test
+     */
+    public function logsToFileWithUnescapedCharacters(): void
+    {
+        $this->setUpVfsStream();
+
+        $recordWithData = GeneralUtility::makeInstance(
+            LogRecord::class,
+            $this->getUniqueId('test.core.log.fileWriter.recordWithData.'),
+            \TYPO3\CMS\Core\Log\LogLevel::INFO,
+            'test record with unicode and slash in data to encode',
+            ['foo' => ['bar' => 'I paid 0.00€ for open source projects/code']]
+        );
+
+        $expectedResult = '{"foo":{"bar":"I paid 0.00€ for open source projects/code"}}';
+
+        $this->createWriter('encoded-data')->writeLog($recordWithData);
+        $logFileContents = trim(file_get_contents($this->getDefaultFileName('encoded-data')));
+        $this->assertContains($expectedResult, $logFileContents);
+    }
+
     /**
      * @test
      * @param LogRecord $record Record Test Data