feat: integrate autoformatting in WriteFile and EditFile commands

We're going to integrate autoformatting into the WriteFile and EditFile commands. After doing the file write with these commands, run the "format" command (as defined by RunCommand) if it exists. You should NOT run the pre/post commit associated with RunCommand (because the formatting should be directly integrated with the edit/write), so make sure you hook into the run command infrastructure at the correct spot.

```git-revs
3f698ba  (Base revision)
c56fb59  Add run_formatter_without_commit to __all__
3a9183d  Add run_formatter_without_commit function to format a specific file without commit operations
13c9c8d  Add run_formatter_without_commit import to write_file.py
d5459f2  Add autoformatting to write_file_content function
4d419ac  Add run_formatter_without_commit import to edit_file.py
2ac534f  Add autoformatting to edit_file_content function
77cf162  Improve run_formatter_without_commit to handle different formatter types
HEAD     Auto-commit format changes
```

codemcp-id: 280-feat-integrate-autoformatting-in-writefile-and-edi
ghstack-source-id: 5815be4
Pull-Request-resolved: #273

Author: ezyang

codemcp/code_command.py

@@ -3,7 +3,7 @@
 import logging
 import os
 import subprocess
-from typing import Any, Dict, List, Optional, cast
+from typing import Any, Dict, List, Optional, Tuple, cast
 
 import tomli
 
@@ -15,6 +15,7 @@
     "get_command_from_config",
     "check_for_changes",
     "run_code_command",
+    "run_formatter_without_commit",
 ]
 
 
@@ -215,3 +216,120 @@ async def run_code_command(
         error_msg = f"Error during {command_name}: {e}"
         logging.error(error_msg)
         return f"Error: {error_msg}"
+
+
+async def run_formatter_without_commit(file_path: str) -> Tuple[bool, str]:
+    """Run the formatter on a specific file without performing pre/post commit operations.
+
+    This function attempts to be flexible in working with different formatter configurations:
+    1. If the formatter is configured to run on specific files (like black path/to/file.py)
+    2. If the formatter is configured to run on all files in a directory
+
+    Args:
+        file_path: Absolute path to the file to format
+
+    Returns:
+        A tuple containing (success_status, message)
+    """
+    try:
+        # Get the project directory (repository root)
+        project_dir = os.path.dirname(file_path)
+        try:
+            project_dir = await get_repository_root(project_dir)
+        except (subprocess.SubprocessError, OSError, ValueError) as e:
+            logging.debug(f"Not in a git repository: {e}")
+            # Fall back to the directory containing the file
+            pass
+
+        # Get the format command from config
+        format_command = get_command_from_config(project_dir, "format")
+        if not format_command:
+            return False, "No format command configured in codemcp.toml"
+
+        # Use relative path from project_dir for the formatting command
+        rel_path = os.path.relpath(file_path, project_dir)
+
+        # First try running the formatter with the specific file path
+        # This works with tools like black, prettier, etc. that accept file paths
+        try:
+            specific_command = format_command.copy() + [rel_path]
+
+            result = await run_command(
+                specific_command,
+                cwd=project_dir,
+                check=True,
+                capture_output=True,
+                text=True,
+            )
+
+            # If we get here, the formatter successfully ran on the specific file
+            truncated_stdout = truncate_output_content(result.stdout, prefer_end=True)
+            return True, f"File formatted successfully:\n{truncated_stdout}"
+        except subprocess.CalledProcessError as e:
+            # If the specific file approach failed, try running the formatter without arguments
+            # This might work for formatters that automatically detect files to format
+            logging.debug(
+                f"Formatter failed with specific file, trying without file path"
+            )
+            try:
+                # Run the formatter without specific file arguments
+                # Some formatters automatically find and format files
+                result = await run_command(
+                    format_command,
+                    cwd=project_dir,
+                    check=True,
+                    capture_output=True,
+                    text=True,
+                )
+
+                # If we get here, the formatter ran successfully
+                truncated_stdout = truncate_output_content(
+                    result.stdout, prefer_end=True
+                )
+                return True, f"File formatted successfully:\n{truncated_stdout}"
+            except subprocess.CalledProcessError:
+                # Both approaches failed, return error from the first attempt
+                # as it's more likely to be relevant to the specific file
+                truncated_stdout = truncate_output_content(
+                    e.output if e.output else "", prefer_end=True
+                )
+                truncated_stderr = truncate_output_content(
+                    e.stderr if e.stderr else "", prefer_end=True
+                )
+
+                # Include both stdout and stderr in the error message
+                stdout_info = (
+                    f"STDOUT:\n{truncated_stdout}"
+                    if truncated_stdout
+                    else "STDOUT: <empty>"
+                )
+                stderr_info = (
+                    f"STDERR:\n{truncated_stderr}"
+                    if truncated_stderr
+                    else "STDERR: <empty>"
+                )
+                return False, f"Formatter failed: {stdout_info}\n{stderr_info}"
+    except subprocess.CalledProcessError as e:
+        # Truncate stdout and stderr if needed
+        truncated_stdout = truncate_output_content(
+            e.output if e.output else "", prefer_end=True
+        )
+        truncated_stderr = truncate_output_content(
+            e.stderr if e.stderr else "", prefer_end=True
+        )
+
+        # Include both stdout and stderr in the error message
+        stdout_info = (
+            f"STDOUT:\n{truncated_stdout}" if truncated_stdout else "STDOUT: <empty>"
+        )
+        stderr_info = (
+            f"STDERR:\n{truncated_stderr}" if truncated_stderr else "STDERR: <empty>"
+        )
+        error_msg = f"Format command failed with exit code {e.returncode}:\n{stdout_info}\n{stderr_info}"
+
+        logging.error(f"Format command failed with exit code {e.returncode}")
+        return False, f"Error: {error_msg}"
+    except Exception as e:
+        error_msg = f"Error during formatting: {e}"
+        logging.error(error_msg)
+        return False, f"Error: {error_msg}"

codemcp/tools/edit_file.py

@@ -9,6 +9,7 @@
 from difflib import SequenceMatcher
 from typing import Any, Dict, List, Tuple
 
+from ..code_command import run_formatter_without_commit
 from ..common import get_edit_snippet
 from ..file_utils import (
     async_open_text,
@@ -773,6 +774,22 @@ async def edit_file_content(
     if read_file_timestamps is not None:
         read_file_timestamps[full_file_path] = os.stat(full_file_path).st_mtime
 
+    # Try to run the formatter on the file
+    format_message = ""
+    formatter_success, formatter_output = await run_formatter_without_commit(
+        full_file_path
+    )
+    if formatter_success:
+        logger.info(f"Auto-formatted {full_file_path}")
+        if formatter_output.strip():
+            format_message = "\nAuto-formatted the file"
+    else:
+        # Only log warning if there was actually a format command configured but it failed
+        if not "No format command configured" in formatter_output:
+            logger.warning(
+                f"Failed to auto-format {full_file_path}: {formatter_output}"
+            )
+
     # Generate a snippet of the edited file to show in the response
     snippet = get_edit_snippet(content, old_string, new_string)
 
@@ -787,4 +804,4 @@ async def edit_file_content(
     else:
         git_message = f"\n\nFailed to commit changes to git: {message}"
 
-    return f"Successfully edited {full_file_path}\n\nHere's a snippet of the edited file:\n{snippet}{git_message}"
+    return f"Successfully edited {full_file_path}\n\nHere's a snippet of the edited file:\n{snippet}{format_message}{git_message}"

codemcp/tools/write_file.py

@@ -1,7 +1,9 @@
 #!/usr/bin/env python3
 
+import logging
 import os
 
+from ..code_command import run_formatter_without_commit
 from ..file_utils import (
     check_file_path_and_permissions,
     check_git_tracking_for_existing_file,
@@ -61,6 +63,18 @@ async def write_file_content(
     # Write the content with UTF-8 encoding and proper line endings
     await write_text_content(file_path, content, "utf-8", line_endings)
 
+    # Try to run the formatter on the file
+    format_message = ""
+    formatter_success, formatter_output = await run_formatter_without_commit(file_path)
+    if formatter_success:
+        logging.info(f"Auto-formatted {file_path}")
+        if formatter_output.strip():
+            format_message = f"\nAuto-formatted the file"
+    else:
+        # Only log warning if there was actually a format command configured but it failed
+        if not "No format command configured" in formatter_output:
+            logging.warning(f"Failed to auto-format {file_path}: {formatter_output}")
+
     # Commit the changes
     git_message = ""
     success, message = await commit_changes(file_path, description, chat_id)
@@ -69,4 +83,4 @@ async def write_file_content(
     else:
         git_message = f"\nFailed to commit changes to git: {message}"
 
-    return f"Successfully wrote to {file_path}{git_message}"
+    return f"Successfully wrote to {file_path}{format_message}{git_message}"

e2e/test_run_command.py

@@ -60,7 +60,16 @@ def test_run_command_with_args(project_dir):
         f.write("test content")
 
     result = subprocess.run(
-        [sys.executable, "-m", "codemcp", "run", "list", test_file, "--path", project_dir],
+        [
+            sys.executable,
+            "-m",
+            "codemcp",
+            "run",
+            "list",
+            test_file,
+            "--path",
+            project_dir,
+        ],
         capture_output=True,
         text=True,
         check=True,
@@ -72,7 +81,15 @@ def test_run_command_error_exit_code(project_dir):
     """Test that error exit codes from the command are propagated."""
     # This should return a non-zero exit code
     process = subprocess.run(
-        [sys.executable, "-m", "codemcp", "run", "exit_with_error", "--path", project_dir],
+        [
+            sys.executable,
+            "-m",
+            "codemcp",
+            "run",
+            "exit_with_error",
+            "--path",
+            project_dir,
+        ],
         capture_output=True,
         text=True,
         check=False,