/editor for VSCode on Windows does not work

[EvitanRelta]

Issue

The problem

On Windows when editor is set to use VSCode, the /editor command fails as below.

$ aider --editor "code --wait"
──────────────────────────────────────────────────────────────────────────────────
Aider v0.72.1
Model: deepseek/deepseek-chat with diff edit format, prompt cache, infinite output
Git repo: .git with 26 files
Repo-map: using 4096 tokens, auto refresh
──────────────────────────────────────────────────────────────────────────────────
> /editor

Unable to complete editor: [WinError 2] The system cannot find the file specified
──────────────────────────────────────────────────────────────────────────────────
>

Cause

The /editor command runs the editor command via subprocess.call(command_parts) at https://github.com/Aider-AI/aider/blob/v0.72.1/aider/editor.py#L133, which on windows, the code command isn't recognised. A simple demo of this is running this script on a Windows machine with VSCode installed:

import subprocess
subprocess.call(["code"])

# $ python test.py
# Traceback (most recent call last):
#   File "C:\path\test.py", line 17, in <module>
#     subprocess.call(["code"])
#   File "C:\path\anaconda3\envs\aider\Lib\subprocess.py", line 389, in call
#     with Popen(*popenargs, **kwargs) as p:
#          ^^^^^^^^^^^^^^^^^^^^^^^^^^^
#   File "C:\path\anaconda3\envs\aider\Lib\subprocess.py", line 1026, in __init__
#     self._execute_child(args, executable, preexec_fn, close_fds,
#   File "C:\path\anaconda3\envs\aider\Lib\subprocess.py", line 1538, in _execute_child
#     hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
#                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
# FileNotFoundError: [WinError 2] The system cannot find the file specified

Possible explaination

When you install VS Code on windows, it adds code.cmd (a batch file) to your PATH, not a true .exe:

import subprocess
subprocess.call(["where", "code"])

# C:\path\Programs\Microsoft VS Code\bin\code      # No extension
# C:\path\Programs\Microsoft VS Code\bin\code.cmd  # .cmd

Batch files can't be executed directly by Python's subprocess with shell=False (the default). They require cmd.exe to interpret them.

With shell=False (default), subprocess uses the Windows API CreateProcess, which:

• Only recognizes .exe, .com, or .bat files directly (but .cmd files require explicit handling).
• Doesn't understand shell-specific features like aliases or batch file execution.

Even if code is in your PATH, CreateProcess fails because it's looking for code.exe (which doesn't exist), not code.cmd.

Solutions

For now, a simple workaround users can do is to use cmd /c code --wait instead of code --wait:

aider --editor "cmd /c code --wait"

And a simple fix would be to run subprocess.call with shell=True. But I'm not sure what consequence shell=True would entail.

subprocess.call(command_parts)
# replace with
subprocess.call(command_parts, shell=True)

I do think /editor should use the current terminal type though. Like if I started aider in Git bash, I'd assume the /editor command would run in Git bash rather than CMD. Perhaps we could use run_cmd_subprocess() in aider/run_cmd.py?

Version and model info

Aider v0.72.1
Model: deepseek/deepseek-chat with diff edit format, prompt cache, infinite output
Git repo: .git with 26 files
Repo-map: using 4096 tokens, auto refresh