trouble with dependent repos

[roger peppe]

On 24 November 2015 at 15:51, Eric Snow <eric.snow at canonical.com> wrote:
> On Mon, Nov 23, 2015 at 9:32 PM, Nate Finch <nate.finch at canonical.com> wrote:
>> Last week, I had trouble landing code in gopkg.in/juju/charm.v6-unstable,
>
> I had a similar experience last week with backward-incompatible
> changes in the utils repo. :(
>
>> and using that code from master of github.com/juju/juju.  I was hoping
>> someone could help me figure out a way to avoid problems I've encountered.
>>
>> [snip]
>>
>> Anyone have ideas on how can we prevent incompatible changes landing in a
>> dependent repo without the corresponding fixes landing in juju soon
>> thereafter?
>
> I'd recommend avoiding backward-incompatible changes if at all
> possible.  Often the temptation is to "fix" some signature while
> you're working on related code.  Sometimes you really need a different
> signature.  Either way, almost every time you can instead introduce a
> new function with the new signature and deprecate the old one.  Using
> that approach you do not break backward compatibility and thus do not
> cause the problem for dependent repos that you've described.

+1 to that.

Unfortunately the charm change was a much bigger one (closely related
to the very reason that charm.v6-unstable was created) so that wasn't
an option there. Sometimes you've just gotta bite the bullet.