Generate only 1, not 2 newlines at the end of baseline

src/Command/AnalyseCommand.php

@@ -11,6 +11,7 @@
 use PHPStan\Command\Symfony\SymfonyOutput;
 use PHPStan\Command\Symfony\SymfonyStyle;
 use PHPStan\File\CouldNotWriteFileException;
+use PHPStan\File\FileReader;
 use PHPStan\File\FileWriter;
 use PHPStan\File\ParentDirectoryRelativePathHelper;
 use PHPStan\File\PathNotFoundException;
@@ -32,6 +33,7 @@
 use function is_array;
 use function is_bool;
 use function is_dir;
+use function is_file;
 use function is_string;
 use function mkdir;
 use function pathinfo;
@@ -279,10 +281,12 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 			$baselineFileDirectory = dirname($generateBaselineFile);
 			$baselineErrorFormatter = new BaselineNeonErrorFormatter(new ParentDirectoryRelativePathHelper($baselineFileDirectory));
 
+			$existingBaselineContent = is_file($generateBaselineFile) ? FileReader::read($generateBaselineFile) : '';
+
 			$streamOutput = $this->createStreamOutput();
 			$errorConsoleStyle = new ErrorsConsoleStyle(new StringInput(''), $streamOutput);
 			$baselineOutput = new SymfonyOutput($streamOutput, new SymfonyStyle($errorConsoleStyle));
-			$baselineErrorFormatter->formatErrors($analysisResult, $baselineOutput);
+			$baselineErrorFormatter->formatErrors($analysisResult, $baselineOutput, $existingBaselineContent);
 
 			$stream = $streamOutput->getStream();
 			rewind($stream);

src/Command/ErrorFormatter/BaselineNeonErrorFormatter.php

@@ -4,11 +4,14 @@
 
 use Nette\DI\Helpers;
 use Nette\Neon\Neon;
+use Nette\Utils\Strings;
 use PHPStan\Command\AnalysisResult;
 use PHPStan\Command\Output;
 use PHPStan\File\RelativePathHelper;
+use PHPStan\ShouldNotHappenException;
 use function ksort;
 use function preg_quote;
+use function substr;
 use const SORT_STRING;
 
 class BaselineNeonErrorFormatter
@@ -21,14 +24,11 @@ public function __construct(private RelativePathHelper $relativePathHelper)
 	public function formatErrors(
 		AnalysisResult $analysisResult,
 		Output $output,
+		string $existingBaselineContent,
 	): int
 	{
 		if (!$analysisResult->hasErrors()) {
-			$output->writeRaw(Neon::encode([
-				'parameters' => [
-					'ignoreErrors' => [],
-				],
-			], Neon::BLOCK));
+			$output->writeRaw($this->getNeon([], $existingBaselineContent));
 			return 0;
 		}
 
@@ -63,13 +63,36 @@ public function formatErrors(
 			}
 		}
 
-		$output->writeRaw(Neon::encode([
+		$output->writeRaw($this->getNeon($errorsToOutput, $existingBaselineContent));
+
+		return 1;
+	}
+
+	/**
+	 * @param array<int, array{message: string, count: int, path: string}> $ignoreErrors
+	 */
+	private function getNeon(array $ignoreErrors, string $existingBaselineContent): string
+	{
+		$neon = Neon::encode([
 			'parameters' => [
-				'ignoreErrors' => $errorsToOutput,
+				'ignoreErrors' => $ignoreErrors,
 			],
-		], Neon::BLOCK));
+		], Neon::BLOCK);
 
-		return 1;
+		if (substr($neon, -2) !== "\n\n") {
+			throw new ShouldNotHappenException();
+		}
+
+		if ($existingBaselineContent === '') {
+			return substr($neon, 0, -1);
+		}
+
+		$existingBaselineContentEndOfFileNewlinesMatches = Strings::match($existingBaselineContent, "~(\n)+$~");
+		$existingBaselineContentEndOfFileNewlines = $existingBaselineContentEndOfFileNewlinesMatches !== null
+			? $existingBaselineContentEndOfFileNewlinesMatches[0]
+			: '';
+
+		return substr($neon, 0, -2) . $existingBaselineContentEndOfFileNewlines;
 	}
 
 }

tests/PHPStan/Command/ErrorFormatter/BaselineNeonErrorFormatterTest.php

@@ -6,11 +6,23 @@
 use Nette\Neon\Neon;
 use PHPStan\Analyser\Error;
 use PHPStan\Command\AnalysisResult;
+use PHPStan\Command\ErrorsConsoleStyle;
+use PHPStan\Command\Symfony\SymfonyOutput;
+use PHPStan\Command\Symfony\SymfonyStyle;
 use PHPStan\File\SimpleRelativePathHelper;
+use PHPStan\ShouldNotHappenException;
 use PHPStan\Testing\ErrorFormatterTestCase;
+use PHPUnit\Framework\Assert;
+use Symfony\Component\Console\Input\StringInput;
+use Symfony\Component\Console\Output\StreamOutput;
+use function fopen;
 use function mt_srand;
+use function rewind;
 use function shuffle;
 use function sprintf;
+use function str_repeat;
+use function stream_get_contents;
+use function substr;
 use function trim;
 
 class BaselineNeonErrorFormatterTest extends ErrorFormatterTestCase
@@ -117,6 +129,7 @@ public function testFormatErrors(
 		$this->assertSame($exitCode, $formatter->formatErrors(
 			$this->getAnalysisResult($numFileErrors, $numGenericErrors),
 			$this->getOutput(),
+			'',
 		), sprintf('%s: response code do not match', $message));
 
 		$this->assertSame(trim(Neon::encode(['parameters' => ['ignoreErrors' => $expected]], Neon::BLOCK)), trim($this->getOutputContent()), sprintf('%s: output do not match', $message));
@@ -139,6 +152,7 @@ public function testFormatErrorMessagesRegexEscape(): void
 		$formatter->formatErrors(
 			$result,
 			$this->getOutput(),
+			'',
 		);
 
 		self::assertSame(
@@ -175,6 +189,7 @@ public function testEscapeDiNeon(): void
 		$formatter->formatErrors(
 			$result,
 			$this->getOutput(),
+			'',
 		);
 		self::assertSame(
 			trim(
@@ -237,6 +252,7 @@ public function testOutputOrdering(array $errors): void
 		$formatter->formatErrors(
 			$result,
 			$this->getOutput(),
+			'',
 		);
 		self::assertSame(
 			trim(Neon::encode([
@@ -284,4 +300,137 @@ public function testOutputOrdering(array $errors): void
 		);
 	}
 
+	/**
+	 * @return Generator<string, array{errors: list<Error>}>
+	 */
+	public function endOfFileNewlinesProvider(): Generator
+	{
+		$existingBaselineContentWithoutEndNewlines = 'parameters:
+	ignoreErrors:
+		-
+			message: "#^Existing error$#"
+			count: 1
+			path: TestfileA';
+
+		yield 'one error' => [
+			'errors' => [
+				new Error('Error #1', 'TestfileA', 1),
+			],
+			'existingBaselineContent' => $existingBaselineContentWithoutEndNewlines . "\n",
+			'expectedNewlinesCount' => 1,
+		];
+
+		yield 'no errors' => [
+			'errors' => [],
+			'existingBaselineContent' => $existingBaselineContentWithoutEndNewlines . "\n",
+			'expectedNewlinesCount' => 1,
+		];
+
+		yield 'one error with 2 newlines' => [
+			'errors' => [
+				new Error('Error #1', 'TestfileA', 1),
+			],
+			'existingBaselineContent' => $existingBaselineContentWithoutEndNewlines . "\n\n",
+			'expectedNewlinesCount' => 2,
+		];
+
+		yield 'no errors with 2 newlines' => [
+			'errors' => [],
+			'existingBaselineContent' => $existingBaselineContentWithoutEndNewlines . "\n\n",
+			'expectedNewlinesCount' => 2,
+		];
+
+		yield 'one error with 0 newlines' => [
+			'errors' => [
+				new Error('Error #1', 'TestfileA', 1),
+			],
+			'existingBaselineContent' => $existingBaselineContentWithoutEndNewlines,
+			'expectedNewlinesCount' => 0,
+		];
+
+		yield 'one error with 3 newlines' => [
+			'errors' => [
+				new Error('Error #1', 'TestfileA', 1),
+			],
+			'existingBaselineContent' => $existingBaselineContentWithoutEndNewlines . "\n\n\n",
+			'expectedNewlinesCount' => 3,
+		];
+
+		yield 'empty existing baseline' => [
+			'errors' => [
+				new Error('Error #1', 'TestfileA', 1),
+			],
+			'existingBaselineContent' => '',
+			'expectedNewlinesCount' => 1,
+		];
+
+		yield 'empty existing baseline, no new errors' => [
+			'errors' => [],
+			'existingBaselineContent' => '',
+			'expectedNewlinesCount' => 1,
+		];
+
+		yield 'empty existing baseline with a newline, no new errors' => [
+			'errors' => [],
+			'existingBaselineContent' => "\n",
+			'expectedNewlinesCount' => 1,
+		];
+
+		yield 'empty existing baseline with 2 newlines, no new errors' => [
+			'errors' => [],
+			'existingBaselineContent' => "\n\n",
+			'expectedNewlinesCount' => 2,
+		];
+	}
+
+	/**
+	 * @dataProvider endOfFileNewlinesProvider
+	 *
+	 * @param list<Error> $errors
+	 */
+	public function testEndOfFileNewlines(
+		array $errors,
+		string $existingBaselineContent,
+		int $expectedNewlinesCount,
+	): void
+	{
+		$formatter = new BaselineNeonErrorFormatter(new SimpleRelativePathHelper(self::DIRECTORY_PATH));
+		$result = new AnalysisResult(
+			$errors,
+			[],
+			[],
+			[],
+			false,
+			null,
+			true,
+		);
+
+		$resource = fopen('php://memory', 'w', false);
+		if ($resource === false) {
+			throw new ShouldNotHappenException();
+		}
+		$outputStream = new StreamOutput($resource, StreamOutput::VERBOSITY_NORMAL, false);
+
+		$errorConsoleStyle = new ErrorsConsoleStyle(new StringInput(''), $outputStream);
+		$output = new SymfonyOutput($outputStream, new SymfonyStyle($errorConsoleStyle));
+
+		$formatter->formatErrors(
+			$result,
+			$output,
+			$existingBaselineContent,
+		);
+
+		rewind($outputStream->getStream());
+
+		$content = stream_get_contents($outputStream->getStream());
+		if ($content === false) {
+			throw new ShouldNotHappenException();
+		}
+
+		if ($expectedNewlinesCount > 0) {
+			Assert::assertSame(str_repeat("\n", $expectedNewlinesCount), substr($content, -$expectedNewlinesCount));
+		}
+		Assert::assertNotSame("\n", substr($content, -($expectedNewlinesCount + 1), 1));
+	}
+
 }