> On Oct 25, 2017, at 6:46 PM, Christopher Collins <[email protected]> wrote:
> 
> On Thu, Oct 19, 2017 at 12:07:58PM -0700, Christopher Collins wrote:
>> On Fri, Oct 13, 2017 at 10:18:14AM -0700, Christopher Collins wrote:
>>> * Because this is an API change, it would be best to introduce it
>>>  slowly.  The `BLE_GAP_CONN_CANCEL` event would be marked deprecated in
>>>  the next release, and then removed entirely in the one after that.
>> 
>> After some discussion in the pull request page
>> (https://github.com/apache/mynewt-core/pull/632), I'm not sure it makes
>> sense to try to slowly "phase out" this behavior.  Since this change
>> represents a change in behavior, rather than the removal of
>> functionality, I don't think there is a good way to deprecate it.  The
>> two basic options are:
>> 
>> 1. Keep deprecated symbols in the code base, but stop using them.  Apps
>> will continue to build without errors, but any app relying on the old
>> behavior will silently break.
>> 
>> 2. Remove unused symbols.  This may introduce build errors for some
>> apps, but at least there is no silent breakage.
>> 
>> We could also try some hybrid approach, e.g., send both types of GAP
>> events when a connection is cancelled.  However, I think this would do
>> more harm than good (and probably introduce some new bugs!).
>> 
>> The release policy document's section on backwards compatibility
>> (https://cwiki.apache.org/confluence/display/MYNEWT/Release+and+Support+Policy#ReleaseandSupportPolicy-BackwardsCompatibility)
>> is pretty clear - if an API change has the potential to break builds,
>> deprecate the old behavior for at least six months before removing it.
>> I think this text needs some additional language for changes such as
>> this one that can't be reasonably phased in.
> 
> I propose we add the following text to the release policy:
> 
>    Sometimes it is impossible or impractical to retain a deprecated
>    version of an API alongside the new one.  For example, a change to
>    a callback function's type, such as the addition of a new parameter,
>    is difficult to introduce while still maintaining the old API.  For
>    these types of changes, the `deprecated` state can be bypassed.
>    Such changes must be voted on by the community before they are
>    implemented.
> 

+1

> If there are no objections, I will make this addition to the wiki.
> 
> Thanks,
> Chris

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