fix bugs from rebase conflicts

mentat/code_file_manager.py

@@ -188,7 +188,7 @@ def get_code_message(self):
 
     def _add_file(self, abs_path):
         logging.info(f"Adding new file {abs_path} to context")
-        self.file_paths.append(abs_path)
+        self.file_paths.append(str(abs_path))
         # create any missing directories in the path
         abs_path.parent.mkdir(parents=True, exist_ok=True)
 
@@ -228,7 +228,6 @@ def _get_new_code_lines(self, rel_path, changes) -> Iterable[str]:
         if not changes:
             return []
 
-        rel_path = str(changes[0].file)
         new_code_lines = self.file_lines[rel_path].copy()
         if new_code_lines != self._read_file(rel_path):
             logging.info(f"File '{rel_path}' changed while generating changes")
@@ -260,7 +259,7 @@ def write_changes_to_files(self, code_changes: list[CodeChange]) -> None:
         for code_change in code_changes:
             # here keys are str not path object
             rel_path = str(code_change.file)
-            abs_path = os.path.join(self.git_root, rel_path)
+            abs_path = self.git_root / rel_path
             match code_change.action:
                 case CodeChangeAction.CreateFile:
                     cprint(f"Creating new file {rel_path}", color="light_green")
@@ -270,23 +269,25 @@ def write_changes_to_files(self, code_changes: list[CodeChange]) -> None:
                 case CodeChangeAction.DeleteFile:
                     self._handle_delete(code_change)
                 case CodeChangeAction.RenameFile:
-                    abs_new_path = os.path.join(self.git_root, code_change.name)
+                    abs_new_path = self.git_root / code_change.name
                     self._add_file(abs_new_path)
-                    code_lines = self.file_lines[abs_path]
+                    code_lines = self.file_lines[rel_path]
                     with open(abs_new_path, "w") as f:
                         f.write("\n".join(code_lines))
                     self._delete_file(abs_path)
                     file_changes[str(code_change.name)] += file_changes[rel_path]
                     file_changes[rel_path] = []
-                    self.file_lines[abs_new_path] = self._read_file(abs_new_path)
+                    self.file_lines[str(code_change.name)] = self._read_file(
+                        abs_new_path
+                    )
                 case _:
                     file_changes[rel_path].append(code_change)
 
         for rel_path, changes in file_changes.items():
-            abs_path = os.path.join(self.git_root, rel_path)
+            abs_path = self.git_root / rel_path
             new_code_lines = self._get_new_code_lines(rel_path, changes)
             if new_code_lines:
-                if abs_path not in self.file_paths:
+                if str(abs_path) not in self.file_paths:
                     raise MentatError(
                         f"Attempted to edit file {abs_path} not in context"
                     )