[PATCH 0/3] batch: don't require checking retvalue of some bitmap ops

Nikolay Shirokovskiy nshirokovskiy at virtuozzo.com
Thu Jul 30 15:49:13 UTC 2020

On 30.07.2020 17:56, Peter Krempa wrote:
> On Thu, Jul 30, 2020 at 17:27:35 +0300, Nikolay Shirokovskiy wrote:
>> Most of bitmap setBit/clearBit/getBit users know that the bitmap index is
>> not out of bound and thus don't check the return value. More precisely
>> the stats is next:
>> Method                all   check
>> ===================================
>> virBitmapSetBit        85      14
>> virBitmapClearBit      15       3
>> virBitmapGetBit        15       6
>> where 'all' is the number of all occurences of the method and 'check' is the
>> number of occurences with 'if (method' pattern.
>> Thus keeping the retvalue checking requirement produces more
>> noise then helps. I guess we even can make these function return
>> void as users can simply compare the index with the bitmap size.
> Well. An ignore_value is not really expensive and it makes the callers
> aware that something needs to be checked.

The only condition these methods can fail is out of bound. Most of
time it is known by the caller that there is no out of bound condition.
So when compiler suggests to check error I personally go and read
the code only to found it can not fail in my circumstances.
At the same time it is quite obvious that these function can not
produce something meaningful for out of bound. That's why
I even thinking of why don't make these methods return void. 

> I don't really see the point of this.
> Additionally, individual patches are missing justification in the commit
> message. Mentioning it in the cover letter is not enough as that doesn't
> get comitted.

I thought that writing same justification 3 times in a row will be
too much. At the same time writing some short version will not explain
things thoroughly. May be I should add good explanation only
to the first patch.


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