On Tue, Nov 06 2018, Steffen Jost wrote:
> Hello!
>
> A brief discussion on the git user mailing list on Google Groups recommended
> me to file the following as a bug report.
>
> The problem led to an actual file loss, but I suspect that this might be
> intended:
>
> 1) .gitignore is added to the repository (which then causes problems)
> 2) A file is added, repeatedly edited and comitted to a remote repository.
> 3) Later on, the file is added to .gitignore and "git rm --cached file" is
> executed (since the file now contains information private to each developer).
> 4) Several commits happen.
> 5) I checkout an old branch which has not yet seen the change in .gitignore
> in the master branch. The file is reverted to the state of the branch.
> 6) I checkout master, and the file with all later changes is irrevocably lost.
>
> I usually advise my students to check-in their .gitignore file into the
> repository. Apparently this is a bad advice, since it now led to a somewhat
> painful file loss for me.
>
> So what is the actual advice on this? Google turned up mixed advice there,
> and the git user mailing list on Google Groups recommended me submitting this
> as a bug here. However, I think this works as intended. However, I don't know
> either how to avert this problem, apart from not checking in the .gitignore
> file (or checking it in under a different name and copying it manually).
This recent thread should be a good starting point:
https://public-inbox.org/git/4c6a1c5b.4030...@workspacewhiz.com/
My reply here I think has an overview of some of the caveats:
https://public-inbox.org/git/871s8qdzph@evledraar.gmail.com/
tl;dr: Git assumes that a pattern in .gitignore means you don't care
about the contents, since it's meant for *.o and the like. This leads to
data loss in some situations (such as yours).
Various suggestions in that thread of ways forward, but none have
been implemented>
