Handle diff of file not yet part of repo

HISTORY.md

@@ -2,7 +2,7 @@
 
 ### main branch
 
-- [Only git commit dirty files that GPT tries to edit](https://aider.chat/docs/faq.html#how-does-aider-use-git)
+- [Only git commit dirty files that GPT tries to edit](https://github.com/paul-gauthier/aider/issues/200#issuecomment-1682750798)
 - Send chat history as prompt/context for Whisper voice transcription
 - Added `--voice-language` switch to constrain `/voice` to transcribe to a specific language
 

aider/coders/base_coder.py

@@ -721,7 +721,6 @@ class Coder:
 
         self.io.tool_output(f"Committing {path} before applying edits.")
         self.need_commit_before_edits.add(path)
-        return
 
     def allowed_to_edit(self, path):
         full_path = self.abs_root_path(path)
@@ -763,6 +762,7 @@ class Coder:
 
         self.abs_fnames.add(full_path)
         self.check_for_dirty_commit(path)
+
         return True
 
     apply_update_errors = 0
@@ -891,6 +891,7 @@ class Coder:
             return
         if not self.repo:
             return
+
         self.repo.commit(fnames=self.need_commit_before_edits)
 
         # files changed, move cur messages back behind the files messages

aider/repo.py

@@ -135,14 +135,20 @@ class GitRepo:
         if not fnames:
             fnames = []
 
+        diffs = ""
+        for fname in fnames:
+            if not self.path_in_repo(fname):
+                diffs += f"Added {fname}\n"
+
         if current_branch_has_commits:
             args = ["HEAD", "--"] + list(fnames)
-            return self.repo.git.diff(*args)
+            diffs += self.repo.git.diff(*args)
+            return diffs
 
         wd_args = ["--"] + list(fnames)
         index_args = ["--cached"] + wd_args
 
-        diffs = self.repo.git.diff(*index_args)
+        diffs += self.repo.git.diff(*index_args)
         diffs += self.repo.git.diff(*wd_args)
 
         return diffs

tests/test_coder.py

@@ -548,6 +548,53 @@ three
 
             self.assertEqual(len(saved_diffs), 2)
 
+    def test_gpt_edit_to_existing_file_not_in_repo(self):
+        with GitTemporaryDirectory():
+            repo = git.Repo()
+
+            fname = Path("file.txt")
+            fname.write_text("one\n")
+
+            fname2 = Path("other.txt")
+            fname2.write_text("other\n")
+            repo.git.add(str(fname2))
+
+            repo.git.commit("-m", "initial")
+
+            io = InputOutput(yes=True)
+            coder = Coder.create(models.GPT4, "diff", io=io, fnames=[str(fname)])
+
+            def mock_send(*args, **kwargs):
+                coder.partial_response_content = f"""
+Do this:
+
+{str(fname)}
+<<<<<<< HEAD
+one
+=======
+two
+>>>>>>> updated
+
+"""
+                coder.partial_response_function_call = dict()
+
+            saved_diffs = []
+
+            def mock_get_commit_message(diffs, context):
+                saved_diffs.append(diffs)
+                return "commit message"
+
+            coder.repo.get_commit_message = MagicMock(side_effect=mock_get_commit_message)
+            coder.send = MagicMock(side_effect=mock_send)
+
+            coder.run(with_message="hi")
+
+            content = fname.read_text()
+            self.assertEqual(content, "two\n")
+
+            diff = saved_diffs[0]
+            self.assertIn("file.txt", diff)
+
 
 if __name__ == "__main__":
     unittest.main()