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Re: Feedback on git-restore




On 16/05/2019 03:18, Junio C Hamano wrote:
Duy Nguyen <pclouds@xxxxxxxxx> writes:

I think it depends on whether use actively use the index, or you
mostly ignore it and always do "git commit -a" and friends.

When you do use the index, the "worktree <-> index <-> HEAD" is the
three stages that you are aware, in that order, and restoring from the
"next" stage is expected.

It does feel natural for me that we "restore worktree from the index"
and "restore index from HEAD". But maybe I'm just too used to the old
way of thinking? Let's see what other people say.
I am somewhat sympathetic to unexperienced users who do not "get"
Git here, but because I still think you cannot make effective use of
Git without understanding the workflow using the index as an "extra"
level sitting between the working tree and the commits, I think it
is a learning experience worth investing in for a new user to get
used to the way of thinking you showed in the above paragraphs.
I would agree.

"the Index" is grossly under-documented and explained. I still don't have a proper understanding of all the multiple Nuances regarding the Index concept. Only a moment ago I was reading a thread that talked about having multiple indexes and the wrong one being referenced or locked.

I tend to map the Index to an old-fashioned 'out-box' on the corner of one's desk (from the days when everything was paper and cc really meant a carbon copy made with carbon paper). One would work on a document and when 'finished' place it in the out-box, which also acted as a work-in-progress (wip) box. Only later would a secretary/mail-person come around to see what needed filing/sending.

The fact that there can be many indexes, with multiple stages (all un-named) is a further source of confusion. For the average user, the only visible artefacts are those in the file system, and perhaps the crisp memory of the last commit. So I can see where Victor is coming from. I don't think we should be solely relying on the experience of user mistakes for their learning.

Maybe we need a `git index` command to make it far more visible to average users (or `git staging-area --show`, with a --cached option ;-).
This is also consistent with other commands, for example "git diff
--staged/--cached" compares the index and HEAD and "git diff" compares
worktree and the index. You would need extra effort e.g. "git diff
HEAD" to compare the worktree and HEAD.
Exactly.

This --index vs --staged was discussed and --staged is a compromise.
The problem is --index means something different in existing
commands. It specifies that you want to target both the index _and_
worktree. --cached on the other hand only targets the index [1].

It's confusing, yes. But --index/--cached is part of Git and we cannot
just ignore our baggage and redefine --index to "just index".
Another thing worth pointing out here may be that a user would stop
feeling it a baggage once the index-centric way of thinking sinks
in.  Because the index is so central to the local use of Git
workflow (i.e. "I am just cloning and pulling from the outside world
to fllow along" does not count), "just the working tree and not the
index" mode is an anomaly, until/unless you start talking about
going backwards (e.g. "I've smudged my working tree by mistake, and
need to recover by copying something out to it", which is the mental
model of "restore").

	Side note: while at the mechanical level what it does is an
	equivalent to what "checkout -- <paths>" does, the mental
	models are different.  "checkout" is still a way to move
	forward "I need the contents of these paths in my next
	commit to look like those in that tree-ish, so copy them out
	to the working tree (to e.g. compile test) and also to the
	index (for e.g. the ease of committing after testing is
	done)".

So the compromise is we leave --index/--cached alone and gradually
move to the --staged/--worktree combo (for other commands as well).
I think what is truly new and valuable is the "working tree only,
bypassing the index" mode, but I am not sure if we want to always
force us to say both when we want to affect both the index and the
working tree, as the index is still central to the local workflow.
I am not sure if there is a wide agreement with such a "gradually
move to" plan.

Also, when you want to only affect the indexed contents, wouldn't
existing "--cached" suffice?

IOW, I do not mind --staged as a synonym for --cached, and --worktree
as a useful addition, but I do not think these new pair should replace
the existing ones.
If the Index is central it need to be to get out from behind the curtain. Just sayin'.

--
Philip