Handle race condition when creating cache directory

CHANGELOG.md

@@ -5,6 +5,7 @@
 - Enh #88: Don't create cache directory on `FileCache` initialization (@vjik)
 - Bug #88: Set correct permissions for nested directories (@vjik)
 - Bug #85: Clear stat cache in `FileCache::set()` (@samdark)
+- Bug #86: Handle race condition when creating cache directory (@vjik)
 
 ## 3.1.0 October 09, 2023
 

src/FileCache.php

@@ -20,12 +20,16 @@
 use function is_dir;
 use function is_file;
 use function iterator_to_array;
+use function mkdir;
 use function opendir;
 use function posix_geteuid;
 use function random_int;
 use function readdir;
+use function restore_error_handler;
 use function rmdir;
 use function serialize;
+use function set_error_handler;
+use function sprintf;
 use function strpbrk;
 use function substr;
 use function unlink;
@@ -191,7 +195,7 @@
             $this->set((string) $key, $value, $ttl);
         }
 
         return true;
     }
 
     public function deleteMultiple(iterable $keys): bool
@@ -325,13 +329,24 @@
         }
 
         if (is_file($path)) {
             throw new CacheException("Failed to create cache directory, file with the same name exists: \"$path\".");
         }
 
-        mkdir($path, recursive: true);
-
-        if (!is_dir($path)) {
-            throw new CacheException("Failed to create cache directory \"$path\".");
+        set_error_handler(
+            static function (int $errorNumber, string $errorString) use ($path): bool {
+                if (is_dir($path)) {
+                    return true;
+                }
+                throw new CacheException(
+                    sprintf('Failed to create directory "%s". %s', $path, $errorString),
+                    $errorNumber,
+                );
+            }
+        );
+        try {
+            mkdir($path, recursive: true);
+        } finally {
+            restore_error_handler();
         }
 
         chmod($path, $this->directoryMode);

tests/FileCacheTest.php

@@ -656,4 +656,13 @@ public function testSetClearsStatCache(): void
         $this->assertTrue($this->cache->set(__FUNCTION__, 'cache2', 2));
         $this->assertSame('cache2', $this->cache->get(__FUNCTION__));
     }
+
+    public function testMkdirConvertingErrorToException(): void
+    {
+        $cache = new FileCache('');
+
+        $this->expectException(CacheException::class);
+        $this->expectExceptionMessage('Failed to create directory "". mkdir(): Invalid path');
+        $cache->set('test', 0);
+    }
 }