Use Version::id() instead of "MD5 over source code" for encoding static analysis cache format in cache keys for static analysis cache

This means that cached static analysis results will be treated as
outdated when a new/different version of php-code-coverage is used even
if the static analysis code has not changed. Optimizing this edge case
for performance is not worth risking errors in the code for calculating
the "MD5 over source code" that we previously used for this.

Author: sebastianbergmann

ChangeLog-10.1.md

@@ -2,6 +2,12 @@
 
 All notable changes are documented in this file using the [Keep a CHANGELOG](http://keepachangelog.com/) principles.
 
+## [10.1.17] - 2025-MM-DD
+
+### Changed
+
+* Changed version identifier for static analysis cache from "MD5 over source code" to `Version::id()`
+
 ## [10.1.16] - 2024-08-22
 
 ### Changed
@@ -113,6 +119,7 @@ All notable changes are documented in this file using the [Keep a CHANGELOG](htt
 
 * The `SebastianBergmann\CodeCoverage\Filter::includeDirectory()`, `SebastianBergmann\CodeCoverage\Filter::excludeDirectory()`, and `SebastianBergmann\CodeCoverage\Filter::excludeFile()` methods are now deprecated
 
+[10.1.17]: https://github.com/sebastianbergmann/php-code-coverage/compare/10.1.16...10.1
 [10.1.16]: https://github.com/sebastianbergmann/php-code-coverage/compare/10.1.15...10.1.16
 [10.1.15]: https://github.com/sebastianbergmann/php-code-coverage/compare/10.1.14...10.1.15
 [10.1.14]: https://github.com/sebastianbergmann/php-code-coverage/compare/10.1.13...10.1.14

src/StaticAnalysis/CachingFileAnalyser.php

@@ -17,7 +17,7 @@
 use function serialize;
 use function unserialize;
 use SebastianBergmann\CodeCoverage\Util\Filesystem;
-use SebastianBergmann\FileIterator\Facade as FileIteratorFacade;
+use SebastianBergmann\CodeCoverage\Version;
 
 /**
  * @internal This class is not covered by the backward compatibility promise for phpunit/php-code-coverage
@@ -26,7 +26,6 @@
  */
 final class CachingFileAnalyser implements FileAnalyser
 {
-    private static ?string $cacheVersion = null;
     private readonly string $directory;
     private readonly FileAnalyser $analyser;
     private readonly bool $useAnnotationsForIgnoringCode;
@@ -152,7 +151,7 @@ private function cacheFile(string $filename): string
                 [
                     $filename,
                     file_get_contents($filename),
-                    self::cacheVersion(),
+                    Version::id(),
                     $this->useAnnotationsForIgnoringCode,
                     $this->ignoreDeprecatedCode,
                 ],
@@ -161,22 +160,4 @@ private function cacheFile(string $filename): string
 
         return $this->directory . DIRECTORY_SEPARATOR . $cacheKey;
     }
-
-    private static function cacheVersion(): string
-    {
-        if (self::$cacheVersion !== null) {
-            return self::$cacheVersion;
-        }
-
-        $buffer = [];
-
-        foreach ((new FileIteratorFacade)->getFilesAsArray(__DIR__, '.php') as $file) {
-            $buffer[] = $file;
-            $buffer[] = file_get_contents($file);
-        }
-
-        self::$cacheVersion = md5(implode("\0", $buffer));
-
-        return self::$cacheVersion;
-    }
 }