Terminal-based editor not working with kart helper

[olsen232]

Describe the bug
Launching a terminal-based editor isn't working from within Kart 0.12.x on macos or linux where the helper mode is enabled. GUI-based editors are unaffected. This is the editor launched in the function run_editor_cmd, that runs $EDITOR

To Reproduce
Steps to reproduce the behaviour:

1. Make sure you are using Kart 0.12 or later
2. Make an uncommitted edit to a kart repo - eg, connect to the working copy and change a dataset's title / add a new feature
3. Run kart commit to commit the edit
4. Editor fails to open, with error message a something like the following:
   Error: There was a problem with the editor 'nano': Command 'nano /Users/olsen232/mykart/repo123/.kart/COMMIT_EDITMSG' returned non-zero exit status 1.

Expected behaviour
An editor should open, in order that you can write the commit message.

Workaround
Disable the helper by running kart like so:
KART_USE_HELPER=0 kart commit
Or, avoid the need to use the editor by specifying a message up front like so:
kart commit -m "commit message"

Version Info

• OS: macOS or linux
• Kart version - 0.12.x

[pfw]

This is due to the helper itself being disconnected from the terminal by the double fork done - there are a couple of cases where this can happen, I believe if GIT_ASKPASS is set and required you will get a similar error. I had considered making a list of commands in the calling process which would automatically skip using the helper as appropriate.

[olsen232]

Fixed as of Kart 0.12.2