chore: raise phpstan to level 8 and fix null safety

- Updated phpstan.neon.dist to level 8
- Added null checks for ReflectionClass::getConstructor() calls in test files
- Enhanced PluginSession to handle nullable instanceId parameter
- Used PHP 8+ null coalescing throw operator for clean error handling
- Improved null safety across test and source files

Key improvements:
- All ReflectionMethod calls now safely handle null returns
- deleteInstance method properly validates required instanceId parameter
- Modern PHP syntax for null safety with descriptive error messages
- No breaking changes to existing functionality

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: Ninerian

phpstan.neon.dist

@@ -1,5 +1,5 @@
 parameters:
-    level: 7
+    level: 8
     paths:
         - ./src
         - ./test

src/PluginSession.php

@@ -86,7 +86,8 @@ public function __construct(
         // delete the instance if the special sub is in the token data
         // exits the request
         if ($sso && $remoteCallHandler && $sso->isDeleteInstanceCall()) {
-            $this->deleteInstance($sso->getInstanceId(), $remoteCallHandler);
+            $instanceId = $sso->getInstanceId() ?: throw new SSOException('Instance id is required for deleteInstance');
+            $this->deleteInstance($instanceId, $remoteCallHandler);
         }
 
         // starts the session

test/PluginSessionTest.php

@@ -115,7 +115,7 @@ public function testConstructorWorksAsExpected(): void
             ->with($this->pluginId);
 
         $reflectedClass = new ReflectionClass($this->classname);
-        $constructor = $reflectedClass->getConstructor();
+        $constructor = $reflectedClass->getConstructor() ?: throw new \Exception('Constructor not found');
         $constructor->invoke($mock, $this->pluginId, $this->publicKey);
 
         $this->setupEnvironment($this->pluginInstanceId, null, false);
@@ -143,7 +143,7 @@ public function testConstructorRejectsSpoofedPID(): void
         $this->expectException(SSOException::class);
 
         $reflectedClass = new ReflectionClass($this->classname);
-        $constructor = $reflectedClass->getConstructor();
+        $constructor = $reflectedClass->getConstructor() ?: throw new \Exception('Constructor not found');
         $constructor->invoke($mock, $this->pluginId, $this->publicKey);
     }
 
@@ -168,7 +168,7 @@ public function testConstructorRefuseEmptyPluginId(): void
         $this->expectExceptionMessage('Empty plugin ID.');
 
         $reflectedClass = new ReflectionClass($this->classname);
-        $constructor = $reflectedClass->getConstructor();
+        $constructor = $reflectedClass->getConstructor() ?: throw new \Exception('Constructor not found');
         $constructor->invoke($mock, '', $this->publicKey);
     }
 
@@ -193,7 +193,7 @@ public function testConstructorRefuseEmptySecret(): void
         $this->expectExceptionMessage('Parameter appSecret for SSOToken is empty.');
 
         $reflectedClass = new ReflectionClass($this->classname);
-        $constructor = $reflectedClass->getConstructor();
+        $constructor = $reflectedClass->getConstructor() ?: throw new \Exception('Constructor not found');
         $constructor->invoke($mock, $this->pluginId, '');
     }
 
@@ -218,7 +218,7 @@ public function testConstructorRefuseEmptyEnv(): void
         $this->expectExceptionMessage('Missing PID or JWT query parameter in Request.');
 
         $reflectedClass = new ReflectionClass($this->classname);
-        $constructor = $reflectedClass->getConstructor();
+        $constructor = $reflectedClass->getConstructor() ?: throw new \Exception('Constructor not found');
         $constructor->invoke($mock, $this->pluginId, $this->publicKey);
     }
 
@@ -243,7 +243,7 @@ public function testConstructorRefuseHavingBothJwtAndPid(): void
         $this->expectExceptionMessage('Tried to initialize the session with both PID and JWT provided.');
 
         $reflectedClass = new ReflectionClass($this->classname);
-        $constructor = $reflectedClass->getConstructor();
+        $constructor = $reflectedClass->getConstructor() ?: throw new \Exception('Constructor not found');
         $constructor->invoke($mock, $this->pluginId, $this->publicKey);
     }
 

test/SSOTokenTest.php

@@ -68,7 +68,7 @@ public function testConstructorRefuseEmptySecret(): void
         $this->expectExceptionMessage('Parameter appSecret for SSOToken is empty.');
 
         $reflectedClass = new ReflectionClass(SSOToken::class);
-        $constructor = $reflectedClass->getConstructor();
+        $constructor = $reflectedClass->getConstructor() ?: throw new \Exception('Constructor not found');
         $constructor->invoke($mock, ' ', 'fake token');
     }
 
@@ -91,7 +91,7 @@ public function testConstructorRefuseEmptyToken(): void
         $this->expectExceptionMessage('Parameter tokenData for SSOToken is empty.');
 
         $reflectedClass = new ReflectionClass(SSOToken::class);
-        $constructor = $reflectedClass->getConstructor();
+        $constructor = $reflectedClass->getConstructor() ?: throw new \Exception('Constructor not found');
         $constructor->invoke($mock, 'fake secret', ' ');
     }