On 7/20/2018 7:02 PM, Elijah Newren wrote:
On Fri, Jul 20, 2018 at 3:05 PM, Junio C Hamano <gitster@xxxxxxxxx> wrote:
Elijah Newren <newren@xxxxxxxxx> writes:
Ah, okay, that's helpful. So, if there are conflicts, it should be
free to clear the skip_worktree flag. Since merge-recursive calls
add_cacheinfo() for all entries it needs to update, which deletes the
old cache entry and just makes new ones, we get that for free.
Correct.
And conversely, if a file-level merge succeeds without conflicts then
it clearly doesn't "need to materialize a working tree file", so it
should NOT clear the skip_worktree flag for that path.
That is not at all implied by what I wrote, though.
If it can be done without too much effort, then it certainly is
nicer to keep the sparseness when we do not have to materialize the
working tree file. But at least in my mind, if it needs too many
special cases, hacks, and conditionals, then it is not worth the
complexity---if it is easier to write a correct code by allowing Git
to populate working tree files, it is perfectly fine to do so.
In a sense, the sparse checkout "feature" itself is a hack by
itself, and that is why I think this part should be "best effort" as
well.
That's good to know, but I don't think we can back out easily:
- Clearing the skip_worktree bit: no big deal, as you mention above
- Avoiding working tree updates when merge doesn't change them: very
desirable[1]
- Doing both: whoops
[1] https://public-inbox.org/git/CA+55aFzLZ3UkG5svqZwSnhNk75=fXJRkvU1m_RHBG54NOoaZPA@xxxxxxxxxxxxxx/
I don't want to regress the bug Linus reported, so to fix Ben's issue,
when we detect that a path's contents/mode won't be modified by the
merge, we can either:
- Update the working tree file if the original cache entry had the
skip_worktree flag set
- Mark the new cache entry as skip_worktree if the original cache
entry had the skip_worktree flag set
Both should be about the same amount of work; the first seems weird
and confusing for future readers of the code. The second makes sense,
but probably should be accompanied with a note in the code about how
there are other codepaths that could consider skip_worktree too.
I'll see if I can put something together, but I have family flying in
tomorrow, and then am out on vacation Mon-Sat next week, so...
I agree with the priorities around proposed behavior with this scenario.
It would be preferred that the skip worktree bit be preserved but the
behavior in 2.17 of clearing it and writing the file to the working
directory is much better than the current 2.18 behavior that makes the
user think they had somehow deleted the file just by doing the merge.
At this point, it isn't clear to the user what they should do to recover
without causing harm to the repo.
$ git status
HEAD detached at df2a63d
You are currently cherry-picking commit 7e6d412.
(all conflicts fixed: run "git cherry-pick --continue")
(use "git cherry-pick --abort" to cancel the cherry-pick operation)
Changes not staged for commit:
(use "git add/rm <file>..." to update what will be committed)
(use "git checkout -- <file>..." to discard changes in working directory)
deleted: foo
