fix: resolve CI linting errors - remove unused imports and update type annotations

src/gdiffer/models.py

@@ -1,7 +1,6 @@
 """Data models for git diff parsing and analysis."""
 
 from dataclasses import dataclass, field
-from typing import Optional
 
 
 @dataclass
@@ -16,6 +15,7 @@ class DiffHunk:
     header: str = ""
 
     def get_added_lines(self) -> list[tuple[int, str]]:
+        """Return tuples of (line_number, content) for added lines."""
         result = []
         for i, line in enumerate(self.new_lines_content):
             if line.startswith('+') and not line.startswith('+++'):
@@ -23,6 +23,7 @@ class DiffHunk:
         return result
 
     def get_removed_lines(self) -> list[tuple[int, str]]:
+        """Return tuples of (line_number, content) for removed lines."""
         result = []
         for i, line in enumerate(self.old_lines_content):
             if line.startswith('-') and not line.startswith('---'):
@@ -30,6 +31,7 @@ class DiffHunk:
         return result
 
     def get_modified_lines(self) -> list[tuple[int, str, str]]:
+        """Return tuples of (old_line, old_content, new_content) for modified lines."""
         result = []
         added = self.get_added_lines()
         removed = self.get_removed_lines()
@@ -44,36 +46,41 @@ class DiffHunk:
 @dataclass
 class DiffFile:
     """Represents a file in the diff with its changes."""
-    old_path: Optional[str]
-    new_path: Optional[str]
-    new_file_mode: Optional[str] = None
-    deleted_file_mode: Optional[str] = None
-    similarity_index: Optional[str] = None
-    rename_from: Optional[str] = None
-    rename_to: Optional[str] = None
+    old_path: str | None
+    new_path: str | None
+    new_file_mode: str | None = None
+    deleted_file_mode: str | None = None
+    similarity_index: str | None = None
+    rename_from: str | None = None
+    rename_to: str | None = None
     hunks: list[DiffHunk] = field(default_factory=list)
     change_type: str = "modify"
 
     @property
     def filename(self) -> str:
+        """Get the current filename."""
         if self.new_path:
             return self.new_path
         return self.old_path or ""
 
     @property
     def is_new(self) -> bool:
+        """Check if this is a new file."""
         return self.new_file_mode is not None or self.old_path in [None, "/dev/null"]
 
     @property
     def is_deleted(self) -> bool:
+        """Check if this file was deleted."""
         return self.deleted_file_mode is not None
 
     @property
     def is_rename(self) -> bool:
+        """Check if this file was renamed."""
         return self.rename_from is not None
 
     @property
     def extension(self) -> str:
+        """Get the file extension."""
         filename = self.filename
         if '.' in filename:
             return filename.rsplit('.', 1)[-1].lower()
@@ -84,7 +91,7 @@ class DiffFile:
 class CodeChange:
     """Represents a code change with context."""
     file: DiffFile
-    hunk: Optional[DiffHunk]
+    hunk: DiffHunk | None
     old_code: str
     new_code: str
     language: str = "unknown"