[ovs-dev] [PATCH] doc: document feature deprecation and removal process

[Ansis Atteka]

On Tue, Sep 22, 2015 at 4:21 AM, Thadeu Lima de Souza Cascardo
<cascardo at redhat.com> wrote:
> On Sat, Sep 19, 2015 at 01:22:39PM -0700, Ansis Atteka wrote:
>> It seems that we haven't defined clear process on how features should
>> be removed from OVS.  This patch attempts to document this process.
>>
>> Singed-off-by: Ansis Atteka <aatteka at nicira.com>
>> ---
>>  CONTRIBUTING.md | 31 +++++++++++++++++++++++++++++++
>>  1 file changed, 31 insertions(+)
>>
>> diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
>> index 12cb7dc..12d2a77 100644
>> --- a/CONTRIBUTING.md
>> +++ b/CONTRIBUTING.md
>> @@ -24,6 +24,8 @@ In particular:
>>
>>    - A patch that adds or removes user-visible features should
>>      also update the appropriate user documentation or manpages.
>> +    Check "Feature Deprecation Guidelines" section in this document
>> +    if you intend to remove user-visible feature.
>>
>>  Testing is also important:
>>
>> @@ -263,6 +265,35 @@ certifies the following:
>>          maintained indefinitely and may be redistributed consistent with
>>          this project or the open source license(s) involved.
>>
>> +Feature Deprecation Guidelines
>> +------------------------------
>> +
>> +Open vSwitch is intended to be user friendly.  This means that under
>> +normal circumstances we don't abruptly remove features from OVS that
>> +some users might still be using.  Otherwise, if we would, then we would
>> +possibly break our user setup when they upgrade and would receive bug
>> +reports.
>> +
>> +Typical process to deprecate a feature in Open vSwitch is to:
>> +
>> +    (a) Mention deprecation of a feature in the NEWS file.  Also, mention
>> +        expected release or absolute time when this feature would be removed
>> +        from OVS altogether.  Don't use relative time (e.g. "in 6 months")
>> +        because that is not clearly interpretable.
>> +
>> +    (b) If Open vSwitch is configured to use deprecated feature it should print
>> +        a warning message to the log files clearly indicating that feature is
>> +        deprecated and that use of it should be avoided.
>> +
>> +    (c) If this feature is mentioned in man pages, then add "Deprecated" keyword
>> +        to it.
>> +
>> +Also, if there is alternative feature to the one that is about to be marked
>> +as deprecated, then mention it in (a), (b) and (c) as well.
>> +
>> +Remember to followup and acctually remove the feature from OVS codebase
>> +once deprecation grace period has expired!
>> +
>>  Comments
>>  --------
>>
>> --
>> 2.1.4
>
> Should it make it clear that deprecation before removal should be part of a
> release? Otherwise, users will not notice the deprecation before the feature is
> removed.

Sorry for late response, I was off last week. If I understand
correctly, then you wanted this document to state more clearly that
"feature deprecation" and "feature removal" must be done in different
releases. I think wording "release after" should help to comprehend
that. So how about following wording:

"Remember to followup and actually remove the feature from OVS codebase
in one of the next releases after deprecation grace period has expired."