fix: Add proper type annotations for Optional parameters

- Use Optional[str] for nullable string parameters
- Use Optional[Path] for nullable path parameters
- Add return type annotations (Optional[object], object) for compile/run methods
- Import typing.Optional in all adapter modules
- Fixes all Pylance type checking warnings

Author: william-yangbo

bootcs/check/adapters/base.py

@@ -24,7 +24,7 @@ class LanguageAdapter(ABC):
         language (str): The programming language (e.g., "c", "python", "java")
     """
 
-    def __init__(self, problem: str, language: str = None):
+    def __init__(self, problem: str, language: Optional[str] = None):
         """
         Initialize the language adapter.
         
@@ -59,7 +59,7 @@ def get_source_file(self) -> Path:
         pass
 
     @abstractmethod
-    def compile(self, *args, **kwargs):
+    def compile(self, *args, **kwargs) -> Optional[object]:
         """
         Compile the source code (if needed for this language).
         
@@ -72,11 +72,14 @@ def compile(self, *args, **kwargs):
         
         Raises:
             CompileError: If compilation fails
+        
+        Returns:
+            Optional process object for validation languages
         """
         pass
 
     @abstractmethod
-    def run(self, *args, stdin=None, **kwargs):
+    def run(self, *args, stdin=None, **kwargs) -> object:
         """
         Run the compiled/interpreted program.
         

bootcs/check/adapters/compiled.py

@@ -29,7 +29,7 @@ class CompiledLanguageAdapter(LanguageAdapter):
         - Java: uses bootcs.check.java module
     """
 
-    def __init__(self, problem: str, language: str = None):
+    def __init__(self, problem: str, language: Optional[str] = None):
         """
         Initialize compiled language adapter.
         
@@ -74,7 +74,7 @@ def get_source_file(self) -> Path:
         """
         return find_source_file(self.problem, self.language)
 
-    def compile(self, *args, **kwargs):
+    def compile(self, *args, **kwargs) -> Optional[object]:
         """
         Compile the source code using language-specific compiler.
         
@@ -101,7 +101,7 @@ def compile(self, *args, **kwargs):
                 f"Compilation not yet implemented for language: {self.language}"
             )
 
-    def run(self, *args, stdin=None, **kwargs):
+    def run(self, *args, stdin=None, **kwargs) -> object:
         """
         Run the compiled program.
         
@@ -140,7 +140,7 @@ class InterpretedLanguageAdapter(LanguageAdapter):
     These languages don't need compilation but still use naming conventions.
     """
 
-    def __init__(self, problem: str, language: str = None):
+    def __init__(self, problem: str, language: Optional[str] = None):
         """
         Initialize interpreted language adapter.
         
@@ -179,7 +179,7 @@ def compile(self, *args, **kwargs):
             # Optionally: py_compile.compile(source_file, doraise=True)
             pass
 
-    def run(self, *args, stdin=None, **kwargs):
+    def run(self, *args, stdin=None, **kwargs) -> object:
         """
         Run the interpreted program.
         

bootcs/check/adapters/conventions.py

@@ -8,6 +8,7 @@
 """
 
 from pathlib import Path
+from typing import Optional
 from typing import Dict, Callable
 
 
@@ -157,7 +158,7 @@ def get_source_filename(problem: str, language: str) -> str:
     return convention(problem)
 
 
-def find_source_file(problem: str, language: str, search_dir: Path = None) -> Path:
+def find_source_file(problem: str, language: str, search_dir: Optional[Path] = None) -> Path:
     """
     Find the source file for a problem in a given language.
     

bootcs/check/adapters/factory.py

@@ -21,8 +21,8 @@
 
 
 def create_adapter(
-    problem: str = None,
-    language: str = None,
+    problem: Optional[str] = None,
+    language: Optional[str] = None,
     adapter_type: str = 'auto'
 ) -> LanguageAdapter:
     """