Re: [PATCHv2 05/10] pkt-line: rename s/packet_read_line/packet_read/

[Jonathan Nieder <jrnieder@gmail.com>]

Jeff King wrote:
> On Mon, Feb 18, 2013 at 02:19:15AM -0800, Jonathan Nieder wrote:

>> In combination with patch 3, this changes the meaning of packet_read()
>> without changing its signature, which could make other patches
>> cherry-picked on top change behavior in unpredictable ways. :(
>>
>> So I'd be all for this if the signature changes (for example to put
>> the fd at the end or something), but not so if not.
>
> True. Though packet_read has only existed since last June, only had one
> callsite (which would now conflict, since I'm touching it in this
> series), and has no new calls in origin..origin/pu. So it's relatively
> low risk for such a problem. I don't know how careful we want to be.

I was unclear.  What I am worried about is that someone using a
version of git without this patch will try some yet-to-be-written
patch using packet_read from the mailing list and not notice that they
are using the wrong function.  For example, if someone is using
1.7.12.y or 1.8.1.y and wants to try a patch from after the above,
they would get subtly different and wrong results.

The rule "change the name or signature when breaking the ABI of a
global function" is easy to remember and follow.  I think we want not
to have to be careful at all, and such rules can help with that. :)

Thanks,
Jonathan