Am 12.07.2013 23:19, schrieb Junio C Hamano:
> Johannes Sixt <j6t@xxxxxxxx> writes:
>
>> We have three independent options that the user can choose in any
>> combination:
>>
>> o --force given or not;
>>
>> o --lockref semantics enabled or not;
>>
>> o refspec with or without +;
>>
>> and these two orthogonal preconditions of the push
>>
>> o push is fast-forward or it is not ("ff", "noff");
>>
>> o the branch at the remote is at the expected rev or it is not
>> ("match", "mismatch").
>>
>> Here is a table with the expected outcome. "ok" means that the push is
>> allowed(*), "fail" means that the push is denied. (Four more lines with
>> --force are omitted because they have "ok" in all spots.)
>>
>> ff noff ff noff
>> match match mismatch mismatch
>>
>> --lockref +refspec ok ok denied denied
>> --lockref refspec ok denied denied denied
>
> I am confused with these. The latter is the most typical:
>
> git fetch
> git checkout topic
> git rebase topic
> git push --lockref topic
>
> where we know it is "noff" already, and we just want to make sure
> that nobody mucked with our remote while we are rebasing.
Today (without --lockref), the above sequence would fail to push.
(Because there is no + and no --force.)
> If nobody updated the remote, why should this push be denied? And in
> order to make it succeed, you need to force with +refspec or --force,
> but that would bypass match/mismatch safety, which makes the whole
> "make sure the other end is unchanged" safety meaningless, no?
I am suggesting that +refspec would *not* override the match/mismatch
safety, but --force would.
>
>> +refspec ok ok ok ok
>
> This is traditional --force.
>
>> refspec ok denied ok denied
>
> We are not asking for --lockref, so match/mismatch does not affect
> the outcome.
I think you are worried that a deviation from the principle that
+refspec == --force hurts current users. But I am arguing that this is
not the case because "current" users do not use --lockref. As you have
seen from the table, without --lockref there is *no change* in behavior.
I still have not seen an example where +refspec != --force would have
unexpected consequences. (The inequality is merely that +refspec fails
on mismatch when --lockref was also given while --force does not.)
>> Notice that without --lockref semantics enabled, +refspec and refspec
>> keep the current behavior.
>
> But I do not think the above table with --lockref makes much sense.
>
> Let's look at noff/match case. That is the only interesting one.
>
> This should fail:
>
> git push topic
>
> due to no-ff.
Yes.
> Your table above makes this fail:
>
> git push --lockref topic
>
> and the user has to force it,
Of course.
> like this?
>
> git push --lockref --force topic ;# or alternatively
> git push --lockref +topic
>
> Why is it even necessary?
Because it is no-ff. How do you achieve the push today (without
--lockref)? You use one of these two options. It does not change with
--lockref.
> If you make
>
> git push --lockref topic
>
> succeed in noff/match case, everything makes more sense to me.
Not to me, obviously ;)
> The --lockref option is merely a weaker form of --force but still a
> way to override the noff check.
No; --lockref only adds the check that the destination is at the
expected revision, but does *NOT* override the no-ff check. Why should
it? (This is not a rethoric question.)
(I think I said differently in an earlier messages, but back then things
were still blurry. The table in my previous message is what I mean.)
> If the user wants to keep noff
> check, the user can simply choose not to use the option.
No. If the user wants to keep the no-ff check, she does not use the + in
the refspec and does not use --force. (Just like today.)
> Of course, that form should fail if "mismatch". And then you can
> force it,
>
> git push --force [--lockref] topic
>
> As "--force" is "anything goes", it does not matter if you give the
> other option on the command line.
... or the + in the refsepc.
-- Hannes
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