Re: [PATCH 1/3] git-branch: add --track and --no-track options

[Paolo Bonzini <paolo.bonzini@lu.unisi.ch>]

>> There is.  The man page says "Scanning stops when an input character 
>> does not match such a format character."  Scanning includes not 
>> processing %n elements, either.
> 
> So, if you want to be that precise, it never says that it does not touch 
> the pointers passed to it.

It cannot know that there *are* any pointers unless it goes on scanning the format string.  Since the function it varargs, it cannot *guess* that there are any without scanning that the documentation says does not happen.  Anyway...

> But it states very clearly what the return 
> value is in case of a failure.

Actually ISTR that %n is not counted in the return value and that's why I wrote the code this way.

> Yes, this is what the source does. But again, the return value is what you 
> should -- and indeed forever can -- rely on. I am not really happy that 
> dwim_ref() touches ref, even if nothing was found, but it is an 
> _implementation detail_.

It's not fair to not have any documentation in the code, force the contributor to reverse engineer the documentation, and say it is relying on an implementation detail.  In otherwise undocumented code, implementation == interface.

Paolo