refactor: move UnableToCountRepoFiles to repo.py and raise from get_tracked_files

aider/main.py

@@ -12,7 +12,7 @@ from prompt_toolkit.enums import EditingMode
 from aider import __version__, models, utils
 from aider.args import get_parser
 from aider.coders import Coder
-from aider.coders.base_coder import UnableToCountRepoFiles
+from aider.repo import UnableToCountRepoFiles
 from aider.commands import Commands, SwitchCoder
 from aider.format_settings import format_settings, scrub_sensitive_info
 from aider.history import ChatSummary

aider/repo.py

@@ -11,6 +11,10 @@ from aider.sendchat import simple_send_with_retries
 from .dump import dump  # noqa: F401
 
 
+class UnableToCountRepoFiles(Exception):
+    pass
+
+
 class GitRepo:
     repo = None
     aider_ignore_file = None
@@ -255,16 +259,22 @@ class GitRepo:
             if commit in self.tree_files:
                 files = self.tree_files[commit]
             else:
+                try:
                     for blob in commit.tree.traverse():
                         if blob.type == "blob":  # blob is a file
                             files.add(blob.path)
                     files = set(self.normalize_path(path) for path in files)
                     self.tree_files[commit] = set(files)
+                except Exception as e:
+                    raise UnableToCountRepoFiles(f"Error traversing commit tree: {str(e)}")
 
         # Add staged files
+        try:
             index = self.repo.index
             staged_files = [path for path, _ in index.entries.keys()]
             files.update(self.normalize_path(path) for path in staged_files)
+        except Exception as e:
+            raise UnableToCountRepoFiles(f"Error getting staged files: {str(e)}")
 
         res = [fname for fname in files if not self.ignored_file(fname)]