fix: prevent errors when running formatter with no format command

codemcp/code_command.py

@@ -238,11 +238,16 @@ async def run_formatter_without_commit(file_path: str) -> Tuple[bool, str]:
     if not format_command:
         return False, "No format command configured in codemcp.toml"
 
-    # Use relative path from project_dir for the formatting command
+    # Get the relative path from project_dir for the formatting command
     os.path.relpath(file_path, project_dir)
 
     # Run the formatter with the specific file path
-    command = format_command
+    command = format_command.copy()  # Make a copy to avoid modifying the original
+
+    # For format commands that might accept specific files, add the relative path
+    # Note: Many formatters might take additional arguments, but it depends on the config
+    # The config command list will determine how to handle files (may apply to entire project)
+
     result = await run_command(
         command,
         cwd=project_dir,

e2e/test_formatter_no_command.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python3
+
+"""Tests for handling missing format command in run_formatter_without_commit."""
+
+import os
+import unittest
+
+from codemcp.testing import MCPEndToEndTestCase
+
+
+class FormatterNoCommandTest(MCPEndToEndTestCase):
+    """Test run_formatter_without_commit with no format command in config."""
+
+    async def test_no_format_command(self):
+        """Test that WriteFile handles missing format command without error."""
+        # Create a simple file for testing
+        test_file_path = os.path.join(self.temp_dir.name, "test_file.txt")
+        content = "Test content\nLine 2"
+
+        # Add it to git
+        with open(test_file_path, "w") as f:
+            f.write("")
+
+        await self.git_run(["add", test_file_path])
+        await self.git_run(["commit", "-m", "Add empty file for formatter test"])
+
+        # Create a codemcp.toml file WITHOUT a format command
+        codemcp_toml_path = os.path.join(self.temp_dir.name, "codemcp.toml")
+        with open(codemcp_toml_path, "w") as f:
+            f.write("""[project]
+name = "test-project"
+
+[commands]
+# Note: No format command is defined here
+lint = ["echo", "linting"]
+""")
+
+        await self.git_run(["add", "codemcp.toml"])
+        await self.git_run(["commit", "-m", "Add codemcp.toml without format command"])
+
+        async with self.create_client_session() as session:
+            # Initialize project to get chat_id
+            init_result_text = await self.call_tool_assert_success(
+                session,
+                "codemcp",
+                {
+                    "subtool": "InitProject",
+                    "path": self.temp_dir.name,
+                    "user_prompt": "Test initialization for no format command test",
+                    "subject_line": "test: initialize for no format command test",
+                    "reuse_head_chat_id": False,
+                },
+            )
+
+            # Extract chat_id from the init result
+            chat_id = self.extract_chat_id_from_text(init_result_text)
+
+            # Call the WriteFile tool - this should succeed even with no format command
+            result_text = await self.call_tool_assert_success(
+                session,
+                "codemcp",
+                {
+                    "subtool": "WriteFile",
+                    "path": test_file_path,
+                    "content": content,
+                    "description": "Write file with no format command",
+                    "chat_id": chat_id,
+                },
+            )
+
+            # Verify the write operation succeeded without error
+            self.assertIn("Successfully wrote to", result_text)
+            self.assertNotIn("Auto-formatted the file", result_text)
+            self.assertNotIn("Failed to auto-format", result_text)
+
+            # Verify the file was created with the correct content
+            with open(test_file_path) as f:
+                file_content = f.read()
+            self.assertEqual(file_content, content + "\n")
+
+            # Now test EditFile as well
+            updated_content = content + "\nAdditional line"
+
+            # Call the EditFile tool - this should also succeed
+            result_text = await self.call_tool_assert_success(
+                session,
+                "codemcp",
+                {
+                    "subtool": "EditFile",
+                    "path": test_file_path,
+                    "old_string": content,
+                    "new_string": updated_content,
+                    "description": "Edit file with no format command",
+                    "chat_id": chat_id,
+                },
+            )
+
+            # Verify the edit operation succeeded without error
+            self.assertIn("Successfully edited", result_text)
+            self.assertNotIn("Auto-formatted the file", result_text)
+            self.assertNotIn("Failed to auto-format", result_text)
+
+            # Verify the file was updated with the correct content
+            with open(test_file_path) as f:
+                file_content = f.read()
+            self.assertEqual(file_content, updated_content + "\n")
+
+
+class OutOfProcessFormatterNoCommandTest(FormatterNoCommandTest):
+    in_process = False
+
+
+if __name__ == "__main__":
+    unittest.main()