Result cache - use file hashes instead of modified times

Author: ondrejmirtes

.github/workflows/build.yml

@@ -308,7 +308,7 @@ jobs:
         uses: actions/cache@v1
         with:
           path: ./tmp
-          key: "result-cache-v1"
+          key: "result-cache-v2"
 
       - name: "PHPStan with result cache"
         run: |

src/Analyser/ResultCache/ResultCacheManager.php

@@ -7,12 +7,11 @@
 use PHPStan\File\FileReader;
 use function array_fill_keys;
 use function array_key_exists;
-use function filemtime;
 
 class ResultCacheManager
 {
 
-	private const CACHE_VERSION = 'v1';
+	private const CACHE_VERSION = 'v2-hashes';
 
 	/** @var string */
 	private $cacheFilePath;
@@ -32,6 +31,9 @@ class ResultCacheManager
 	/** @var string */
 	private $usedLevel;
 
+	/** @var array<string, string> */
+	private $fileHashes = [];
+
 	/**
 	 * @param string $cacheFilePath
 	 * @param string[] $allCustomConfigFiles
@@ -113,15 +115,12 @@ public function restore(array $allAnalysedFiles, bool $debug): ResultCache
 			unset($deletedFiles[$analysedFile]);
 
 			$analysedFileData = $invertedDependencies[$analysedFile];
-			$cachedModifiedTime = $analysedFileData['modifiedTime'];
+			$cachedFileHash = $analysedFileData['fileHash'];
 			$dependentFiles = $analysedFileData['dependentFiles'];
 			$invertedDependenciesToReturn[$analysedFile] = $dependentFiles;
-			$currentModifiedTime = filemtime($analysedFile);
-			if ($currentModifiedTime === false) {
-				$currentModifiedTime = time();
-			}
+			$currentFileHash = $this->getFileHash($analysedFile);
 
-			if ($cachedModifiedTime === $currentModifiedTime) {
+			if ($cachedFileHash === $currentFileHash) {
 				continue;
 			}
 
@@ -293,12 +292,8 @@ private function save(
 		foreach ($dependencies as $file => $fileDependencies) {
 			foreach ($fileDependencies as $fileDep) {
 				if (!array_key_exists($fileDep, $invertedDependencies)) {
-					$modifiedTime = filemtime($fileDep);
-					if ($modifiedTime === false) {
-						$modifiedTime = time();
-					}
 					$invertedDependencies[$fileDep] = [
-						'modifiedTime' => $modifiedTime,
+						'fileHash' => $this->getFileHash($fileDep),
 						'dependentFiles' => [],
 					];
 					unset($filesNoOneIsDependingOn[$fileDep]);
@@ -316,12 +311,8 @@ private function save(
 				continue;
 			}
 
-			$modifiedTime = filemtime($file);
-			if ($modifiedTime === false) {
-				$modifiedTime = time();
-			}
 			$invertedDependencies[$file] = [
-				'modifiedTime' => $modifiedTime,
+				'fileHash' => $this->getFileHash($file),
 				'dependentFiles' => [],
 			];
 		}
@@ -385,10 +376,17 @@ private function getConfigFiles(): array
 
 	private function getFileHash(string $path): string
 	{
+		if (array_key_exists($path, $this->fileHashes)) {
+			return $this->fileHashes[$path];
+		}
+
 		$contents = FileReader::read($path);
 		$contents = str_replace("\r\n", "\n", $contents);
 
-		return sha1($contents);
+		$hash = sha1($contents);
+		$this->fileHashes[$path] = $hash;
+
+		return $hash;
 	}
 
 	private function getPhpStanVersion(): string

tests/e2e/ResultCacheEndToEndTest.php

@@ -42,7 +42,11 @@ public function testResultCache(): void
 		$lexerCode = str_replace('@param string $code', '', $lexerCode);
 		$lexerCode = str_replace('public function startLexing($code', 'public function startLexing(\\PhpParser\\Node\\Expr\\MethodCall $code', $lexerCode);
 		file_put_contents($lexerPath, $lexerCode);
-		touch(__DIR__ . '/PHP-Parser/lib/PhpParser/ErrorHandler.php');
+
+		$errorHandlerPath = __DIR__ . '/PHP-Parser/lib/PhpParser/ErrorHandler.php';
+		$errorHandlerContents = FileReader::read($errorHandlerPath);
+		$errorHandlerContents .= "\n\n";
+		file_put_contents($errorHandlerPath, $errorHandlerContents);
 
 		$bootstrapPath = __DIR__ . '/PHP-Parser/lib/bootstrap.php';
 		$originalBootstrapContents = FileReader::read($bootstrapPath);