diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index e304bcdf2..c0a16499a 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -971,8 +971,15 @@ class Coder:
         if not self.repo:
             return []
 
-        files = self.repo.git.execute(["git", "-c", "core.quotepath=off", "ls-files"])
-        files = set(files.splitlines())
+        try:
+            commit = self.repo.head.commit
+        except ValueError:
+            return set()
+
+        files = []
+        for blob in commit.tree.traverse():
+            if blob.type == "blob":  # blob is a file
+                files.append(blob.path)
 
         # convert to appropriate os.sep, since git always normalizes to /
         res = set(str(Path(PurePosixPath(path))) for path in files)
diff --git a/tests/test_coder.py b/tests/test_coder.py
index 756840740..403bf0805 100644
--- a/tests/test_coder.py
+++ b/tests/test_coder.py
@@ -30,9 +30,9 @@ class TestCoder(unittest.TestCase):
         coder = Coder.create(models.GPT4, None, mock_io, openai_api_key="fake_key")
 
         # Mock the git repo
-        mock_repo = MagicMock()
-        mock_repo.git.execute.return_value = "file1.txt\nfile2.py"
-        coder.repo = mock_repo
+        mock = MagicMock()
+        mock.return_value = set(["file1.txt", "file2.py"])
+        coder.get_tracked_files = mock
 
         # Call the check_for_file_mentions method
         coder.check_for_file_mentions("Please check file1.txt and file2.py")
@@ -76,10 +76,9 @@ class TestCoder(unittest.TestCase):
         # Initialize the Coder object with the mocked IO and mocked repo
         coder = Coder.create(models.GPT4, None, mock_io, openai_api_key="fake_key")
 
-        # Mock the git repo
-        mock_repo = MagicMock()
-        mock_repo.git.execute.return_value = "file1.txt\nfile2.py"
-        coder.repo = mock_repo
+        mock = MagicMock()
+        mock.return_value = set(["file1.txt", "file2.py"])
+        coder.get_tracked_files = mock
 
         # Call the check_for_file_mentions method
         coder.check_for_file_mentions("Please check file1.txt and file2.py")
@@ -103,10 +102,9 @@ class TestCoder(unittest.TestCase):
         # Initialize the Coder object with the mocked IO and mocked repo
         coder = Coder.create(models.GPT4, None, mock_io, openai_api_key="fake_key")
 
-        # Mock the git repo
-        mock_repo = MagicMock()
-        mock_repo.git.execute.return_value = "file1.txt\nother/file1.txt"
-        coder.repo = mock_repo
+        mock = MagicMock()
+        mock.return_value = set(["file1.txt", "other/file1.txt"])
+        coder.get_tracked_files = mock
 
         # Call the check_for_file_mentions method
         coder.check_for_file_mentions("Please check file1.txt!")
@@ -376,6 +374,8 @@ class TestCoder(unittest.TestCase):
             file_path.touch()
             repo.git.add(str(file_path))
 
+        repo.git.commit("-m", "added")
+
         # Create a Coder object on the temporary directory
         coder = Coder.create(
             models.GPT4,