Re: [RFC] stash --continue

From: Marc Branchaud <marcnarc@xiplink.com>
Date: Jan 18, 2017, 18:44 UTC
Message-ID: <38d592b8-975c-1fd9-4c42-877e34a4ab70@xiplink.com>
In-Reply-To: <alpine.DEB.2.20.1701181725130.3469@virtualbox>

On 2017-01-18 11:34 AM, Johannes Schindelin wrote:

Show 34 quoted lines

> Hi Marc,
>
> On Wed, 18 Jan 2017, Marc Branchaud wrote:
>
>> On 2017-01-16 05:54 AM, Johannes Schindelin wrote:
>>
>>> On Mon, 16 Jan 2017, Stephan Beyer wrote:
>>>
>>>> a git-newbie-ish co-worker uses git-stash sometimes. Last time he
>>>> used "git stash pop", he got into a merge conflict. After he
>>>> resolved the conflict, he did not know what to do to get the
>>>> repository into the wanted state. In his case, it was only "git add
>>>> <resolved files>" followed by a "git reset" and a "git stash drop",
>>>> but there may be more involved cases when your index is not clean
>>>> before "git stash pop" and you want to have your index as before.
>>>>
>>>> This led to the idea to have something like "git stash
>>>> --continue"[1]
>>>
>>> More like "git stash pop --continue". Without the "pop" command, it
>>> does not make too much sense.
>>
>> Why not?  git should be able to remember what stash command created the
>> conflict.  Why should I have to?  Maybe the fire alarm goes off right when I
>> run the stash command, and by the time I get back to it I can't remember
>> which operation I did.  It would be nice to be able to tell git to "just
>> finish off (or abort) the stash operation, whatever it was".
>
> That reeks of a big potential for confusion.
>
> Imagine for example a total Git noob who calls `git stash list`, scrolls
> two pages down, then hits `q` by mistake. How would you explain to that
> user that `git stash --continue` does not continue showing the list at the
> third page?

Sorry, but I have trouble taking that example seriously. It assumes such a level of "noobness" that the user doesn't even understand how standard command output paging works, not just with git but with any shell command.

> Even worse: `git stash` (without arguments) defaults to the `save`
> operation, so any user who does not read the documentation (and who does?)
> would assume that `git stash --continue` *also* implies `save`.

Like the first example, your user is trying to "continue" a command that is already complete. It's like try to do "git rebase --continue" when there's no rebase operation underway.

Now, maybe there is some way for "git stash save" (implied or explicit) to stop partway through the operation. I can't imagine such a situation (out of disk space, maybe?), particularly where the user would expect "git stash save" to leave things in a half-finished state. To me "git stash save" should be essentially all-or-nothing.

However, if there were such a partial-failure scenario, then I think it would be perfectly reasonable for "git stash --continue" to finish the save operation, assuming that the failure condition has been resolved.

Show 6 quoted lines

> If that was not enough, there would still be the overall design of Git's
> user interface. You can call it confusing, inconsistent, with a lot of
> room for improvement, and you would be correct. But none of Git's commands
> has a `--continue` option that remembers the latest subcommand and
> continues that. To introduce that behavior in `git stash` would disimprove
> the situation.

I think it's more the case that none of the current continuable commands have subcommands (though I can't think of all the continuable or abortable operations offhand, so maybe I'm wrong). I think we're discussing new UI ground here.

And since the pattern is already "git foo --continue", it seems more consistent to me for it to be "git stash --continue" as well. Especially since there can be only one partially-complete stash sub-operation at one time (per workdir, at least). So there's no reason to change the pattern just for the stash command.

Think of it this way: All the currently continuable/abortable commands put the repository in a shaky state, where performing certain other operations would be ill advised. Attempting to start a rebase while a merge conflict is unresolved, for example. IIRC, git actually tries to stop users from shooting their feet in this way.

And so it should be for the stash operation: If applying a stash yields a conflict, it has to be resolved or aborted before something like a rebase or merge is attempted. It doesn't matter which stash subcommand created the shaky situation.

In the long run, I think there's even the possibility of generic "git continue" and "git abort" commands, that simply continue or abort the current partially-complete operation, whatever it is. (Isn't that the ultimate goal of all the "sequencer" work? I admit I have not been following that effort.)

> With every new feature, it is not enough to consider its benefits. You
> always have to take the potential fallout into account, too.

Agreed.

> At least `git stash pop --continue` would be consistent with all other
> `--continue` options in Git that I can think of...

Alas, I disagree!

M.