Re: [PATCH 01/23] contrib/coccinnelle: add equals-null.cocci

> Junio C Hamano <gitster@pobox.com> writes:
>
>> To avoid unnecessary conflicts with in-flight topics, ideally, we
>> perhaps could do something along this line:
>>
>>  * Pick a recent stable point that is an ancestor of all topics in
>>    flight.  Add the new coccinelle rule file, take "make coccicheck"
>>    output and create a two-patch series like Philip suggested.  Queue
>>    the result in a topic branch B.
>>
>>  * For each topic in flight T, make a trial merge of T into B, and
>>    examine "make coccicheck" output.  Any new breakages such a test
>>    finds are new violations the topic T introduces.  Discard the
>>    result of the trial merge, and add one commit to topic T that
>>    corrects the violations the topic introduced, and send that fixup
>>    to the author of the topic for consideration when the topic is
>>    rerolled (or if the topic is in 'next', acked to be queued on
>>    top).  Do not fix the violations that is corrected when branch B
>>    was prepared above.
>>
>> As I assumed that applying the patches in this series would create
>> the branch B, and then I saw that the tip of 'seen' after merging
>> this topic still needed to have a lot more fixes according to "make
>> coccicheck", I got a (false) impression that there are too many new
>> violations from topics in flight, which was the primary source of my
>> negative reaction against potential code churn.  If we try the above
>> exercise, perhaps there may not be too many topics that need fix-up
>> beyond what we fix in the branch B, and if that is the case, I would
>> not be so negative.
> So I tried that myself, and the topic branch B was fairly
> straightforward to create.
>
> We have ~60 topics in flight (not counting this one), and it turns
> out that there is no topic that introduces new code that fails the
> equals-null.cocci rule.  IOW, the follow-up fixup per topic turns
> out to be an empty set.
>
> So, I'd probably use the [01/23] and then a single ~5k lines patch
> that was generated with equals-null.cocci rule as the branch B
> above, let it percolate down from 'seen' to 'next' to eventually
> 'master'.
>
> Thanks.