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Store the result cache with serialize() instead of a var_export'd PHP file #5982

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Store the result cache with serialize() instead of a var_export'd PHP file #5982

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138 changes: 44 additions & 94 deletions src/Analyser/ResultCache/ResultCacheManager.php
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Original file line number Diff line number Diff line change
Expand Up @@ -17,9 +17,10 @@
use PHPStan\DependencyInjection\GenerateFactory;
use PHPStan\DependencyInjection\ProjectConfigHelper;
use PHPStan\File\CouldNotReadFileException;
use PHPStan\File\CouldNotWriteFileException;
use PHPStan\File\FileFinder;
use PHPStan\File\FileHelper;
use PHPStan\File\FileReader;
use PHPStan\File\FileWriter;
use PHPStan\Internal\ArrayHelper;
use PHPStan\Internal\ComposerHelper;
use PHPStan\PhpDoc\StubFilesProvider;
Expand All @@ -36,11 +37,7 @@
use function array_unique;
use function array_values;
use function count;
use function error_get_last;
use function explode;
use function fclose;
use function fopen;
use function fwrite;
use function get_loaded_extensions;
use function getenv;
use function hash_file;
Expand All @@ -50,13 +47,15 @@
use function is_file;
use function ksort;
use function microtime;
use function serialize;
use function sort;
use function sprintf;
use function str_starts_with;
use function strlen;
use function substr;
use function time;
use function unlink;
use function var_export;
use function unserialize;
use const PHP_VERSION_ID;

/**
Expand All @@ -69,6 +68,15 @@ final class ResultCacheManager

private const CACHE_VERSION = 'v13-packageDependencies';

/**
* The cache file is serialize() output, but an older PHPStan reading it would
* include it as PHP and echo the whole multi-megabyte content to stdout as
* inline text before discarding it. This prefix makes such an include return
* null immediately (the text after ?> is never reached), so a downgrade
* degrades to a silent full analysis instead.
*/
private const SERIALIZED_FILE_PREFIX = '<?php return; ?>';

/** @var array<string, string> */
private array $fileHashes = [];

Expand Down Expand Up @@ -206,7 +214,16 @@ public function restore(array $allAnalysedFiles, bool $debug, bool $onlyFiles, ?
}

try {
$data = require $cacheFilePath;
// The cache used to be a var_export'd PHP file loaded via include. Including a
// multi-megabyte PHP source retains its compiled op_arrays and interned strings
// for the process lifetime; unserialize() produces only the values. A cache file
// in the old PHP format fails to unserialize and is discarded below like any
// other corrupted file, so no cache version bump is needed for the transition.
$contents = FileReader::read($cacheFilePath);
if (str_starts_with($contents, self::SERIALIZED_FILE_PREFIX)) {
$contents = substr($contents, strlen(self::SERIALIZED_FILE_PREFIX));
}
$data = @unserialize($contents);
} catch (Throwable $e) {
if ($output->isVeryVerbose()) {
$output->writeLineFormatted(sprintf('Result cache not used because an error occurred while loading the cache file: %s', $e->getMessage()));
Expand Down Expand Up @@ -402,12 +419,12 @@ public function restore(array $allAnalysedFiles, bool $debug, bool $onlyFiles, ?
$filesToAnalyse = [];
$invertedDependenciesToReturn = [];
$invertedUsedTraitDependenciesToReturn = [];
$errors = $data['errorsCallback']();
$locallyIgnoredErrors = $data['locallyIgnoredErrorsCallback']();
$errors = $data['errors'];
$locallyIgnoredErrors = $data['locallyIgnoredErrors'];
$linesToIgnore = $data['linesToIgnore'];
$unmatchedLineIgnores = $data['unmatchedLineIgnores'];
$collectedData = $data['collectedDataCallback']();
$exportedNodes = $data['exportedNodesCallback']();
$collectedData = $data['collectedData'];
$exportedNodes = $data['exportedNodes'];
$filteredErrors = [];
$filteredLocallyIgnoredErrors = [];
$filteredLinesToIgnore = [];
Expand Down Expand Up @@ -1158,89 +1175,22 @@ private function save(

$file = $this->cacheFilePath;

// streamed to the file section by section - building the whole
// var_export()ed contents in memory at once would take up roughly
// twice the size of the resulting file in the main process
$handle = @fopen($file, 'w');
if ($handle === false) {
$error = error_get_last();
throw new CouldNotWriteFileException($file, $error !== null ? $error['message'] : 'unknown cause');
}

try {
$this->writeToHandle($handle, $file, "<?php declare(strict_types = 1);

return [
'lastFullAnalysisTime' => " . var_export($lastFullAnalysisTime, true) . ",
'meta' => " . var_export($meta, true) . ",
'projectExtensionFiles' => " . var_export($projectExtensionFiles, true) . ",
'errorsCallback' => static function (): array { return ");
$this->streamArrayVarExportToHandle($handle, $file, $errors);
$this->writeToHandle($handle, $file, "; },
'locallyIgnoredErrorsCallback' => static function (): array { return ");
$this->streamArrayVarExportToHandle($handle, $file, $locallyIgnoredErrors);
$this->writeToHandle($handle, $file, "; },
'linesToIgnore' => ");
$this->streamArrayVarExportToHandle($handle, $file, $linesToIgnore);
$this->writeToHandle($handle, $file, ",
'unmatchedLineIgnores' => ");
$this->streamArrayVarExportToHandle($handle, $file, $unmatchedLineIgnores);
$this->writeToHandle($handle, $file, ",
'collectedDataCallback' => static function (): array { return ");
$this->streamArrayVarExportToHandle($handle, $file, $collectedData);
$this->writeToHandle($handle, $file, "; },
'dependencies' => ");
$this->streamArrayVarExportToHandle($handle, $file, $invertedDependencies);
$this->writeToHandle($handle, $file, ",
'packageDependencies' => ");
$this->streamArrayVarExportToHandle($handle, $file, $packageDependencies);
$this->writeToHandle($handle, $file, ",
'exportedNodesCallback' => static function (): array { return ");
$this->streamArrayVarExportToHandle($handle, $file, $exportedNodes);
$this->writeToHandle($handle, $file, '; },
];
');
} finally {
fclose($handle);
}
}

/**
* @param resource $handle
*/
private function writeToHandle($handle, string $file, string $contents): void
{
if (@fwrite($handle, $contents) === false) {
$error = error_get_last();
throw new CouldNotWriteFileException($file, $error !== null ? $error['message'] : 'unknown cause');
}
}

/**
* Streams the var_export() representation of an array to the file entry
* by entry, producing output byte-identical to var_export($values, true).
*
* var_export() builds the whole export in memory even when told to print it,
* so exporting a big section in one call would take up as much memory
* as the resulting file section itself.
*
* Each entry is exported wrapped in a single-entry array whose "array (\n"
* prefix and "\n)" suffix are stripped, yielding the same bytes (including
* indentation) the entry would get inside the full export. Indenting the lines
* of a standalone value export would corrupt multi-line string contents instead.
*
* @param resource $handle
* @param array<mixed> $values
*/
private function streamArrayVarExportToHandle($handle, string $file, array $values): void
{
$this->writeToHandle($handle, $file, 'array (');
foreach ($values as $key => $value) {
$entry = var_export([$key => $value], true);
$this->writeToHandle($handle, $file, "\n" . substr($entry, 8, -2));
}

$this->writeToHandle($handle, $file, "\n)");
FileWriter::write(
$file,
self::SERIALIZED_FILE_PREFIX . serialize([
'lastFullAnalysisTime' => $lastFullAnalysisTime,
'meta' => $meta,
'projectExtensionFiles' => $projectExtensionFiles,
'errors' => $errors,
'locallyIgnoredErrors' => $locallyIgnoredErrors,
'linesToIgnore' => $linesToIgnore,
'unmatchedLineIgnores' => $unmatchedLineIgnores,
'collectedData' => $collectedData,
'dependencies' => $invertedDependencies,
'packageDependencies' => $packageDependencies,
'exportedNodes' => $exportedNodes,
]),
);
}

/**
Expand Down
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