Re: [Bug] Stashing during merge loses MERGING state

[Elijah Newren <newren@gmail.com>]

On Thu, Mar 11, 2021 at 11:07 PM Chris Torek <chris.torek@gmail.com> wrote:
>
> On Thu, Mar 11, 2021 at 9:19 PM Phil Hord <phil.hord@gmail.com> wrote:
> > I wonder if a fix could be as simple as recording the MERGE_HEAD as
> > the third parent commit of the stash ref.
>
> There is already a third parent, but only when using -u / -a: this
> third-parent commit holds the untracked files (which are then removed
> a la `git clean`).
>
> A better trick would, I think, be able to save a partial merge state
> in general, including the unmerged statuses of various files, the
> ongoing action (merge or one of the other things that use it), and
> so on, in a form that could be restored later.  A plain `git stash` in
> any partially-merged state should tell you: no, use the fancier
> merge-state-saver instead.
>
> > I think being able to stash during a merge conflict could be very
> > useful.  I do sometimes need to get back to a working state
> > momentarily and a merge conflict represents a long pole to doing so.
> > Similarly, it could be useful to stash a conflicted `git rebase` so I
> > could return to it later and pick up where I left off.  Now we really
> > would need to store some extra metadata, though, like the todo-list
> > and ORIG_HEAD.  And we would definitely need some extra command line
> > switch to tell stash (or rebase) that I want to include all the rebase
> > state and also "pause" the rebase by restoring to my starting point.
>
> This is the sort of thing I'm thinking of, for the "superstash" (terrible
> name for it). Note that whatever this becomes, it should be send-able
> (via push and/or email) so that you can have multiple people work
> on resolving a particularly hairy merge.

You can use git-imerge (https://github.com/mhagger/git-imerge) for
that...just not once you've already started a merge (unless you're
willing to undo and restart).

As per my other email, I'm pretty worried about attempting to stash a
merge, given that stash allows its contents to be "reapplied" on top
of a different commit.  That works fine for single-parent commits, but
merges have multiple parents and it'd be rather tricky to reapply such
a stash on a different base without creating an evil merge.  Perhaps
if "superstash" forced you to only reapply on the same base then it'd
be fine...but it's starting to no longer be a "stash" anymore but
something else.