Set commit message for staged files externally?

[davidfraser]

I have external tools producing a set of changes and staging them, and writing a commit message, but I'd like to review the changes in SourceGit before actually committing. Is it possible to write a git message to a file somewhere so that sourcegit will read it (like .git/GITGUI_MSG for git gui?) if switching to the LOCAL CHANGES view and no message is in the GUI already?

[love-linger]

Suppose that users can write and submit information to the $GIT_DIR/SOURCEGIT_COMMITMSG file.

• Is it necessary to watch this file in Models.Watcher (a realtime filesystem watcher to detect if some file has been added/changed/renamed)? For example, if the user has already opened the repository in SourceGit and is on the LOCAL CHANGES page, how can SourceGit know the file is changed and ready to be readed?
• When will this file be deleted? If it will not be deleted, then every time the repository is opened in SourceGit, how can SourceGit determine whether the content of the file has already been used? If SourceGit deletes the file after reading it, then how to ensure whether the file is being written to externally?

[davidfraser]

Good questions! Some thoughts:

• SourceGit does seem to remember previous commit messages already; sometimes after doing a merge I see that the merge commit message, which was committed, appears in the commit message panel - that may just be a bug
• For my use case, it would be sufficient to check if the file has changed (with a stat check - for last modified time/existence) if:
  • the user changes to the Local Changes view
  • the user switches back to the SourceGit window (it gets the focus) after it has lost the focus, and the Local Changes view is active
    I don't think it requires watching or constant checking of the file.
• On deleting the file - I would assume that SourceGit should regard the message as stale, if the file timestamp is earlier than the last commit performed in that repository. That way, SourceGit doesn't have to delete the file, but any new messages written to it will be detected...
  What do you think?