magit/magit — comment on commit d4a3dff143efbecd62f86b2bf2b307a74a6473cd
File:  line 0
By pjweisberg:

Normally `server-edit` doesn't care if the buffer is read only. My guess is that you have something in your `before-save-hook` that's trying to edit the buffer. Maybe `before-save-hook`s should be disabled in rebase-mode?