Re: [PATCH] misra: comment default case in single-clause switch

[Jan Beulich <jbeulich@xxxxxxxx>]

On 12.08.2025 09:19, Dmytro Prokopchuk1 wrote:
> 
> 
> On 8/12/25 00:14, Nicola Vetrini wrote:
>> On 2025-08-11 19:36, Dmytro Prokopchuk1 wrote:
>>> MISRA Rule 16.4: Every switch statement shall have a default label. The
>>> default clause must contain either a statement or a comment prior to its
>>> terminating break statement.
>>>
>>> This change adds comments in default cases in single-clause switches to
>>> avoid violations of the rule where the `default` clause lacks a suitable
>>> comment or statement.
>>>
>>
>> If you want to go this way then at least this config wants dropping:
>>
>> -doc_begin="A switch statement with a single switch clause and no 
>> default label may be used in place of an equivalent if statement if it 
>> is considered to improve readability."
>> -config=MC3A2.R16.4,switch_clauses+={deliberate,"switch(1)&&default(0)"}
>> -doc_end
>>
>> and probably this one too (haven't checked):
>>
>> -doc_begin="A switch statement with a single switch clause and no 
>> default label may be used in place of an equivalent if statement if it 
>> is considered to improve readability."
>> -config=MC3A2.R16.6,switch_clauses+={deliberate, "default(0)"}
>> -doc_end
>>
>> In the end it's a tradeoff; placing a comment with a suitable 
>> argumentation might be strictly better than simply tagging the tool 
>> report, at least from a developer's perspective. From a MISRA compliance 
>> standpoint in my opinion both are fine. Let's see what the maintainers 
>> think.
>>
> 
> According to Jan's comment here
> https://patchew.org/Xen/725ec86ac1aa883c35fb30b8f226c95cbe0934e9.1754322299.git.dmytro._5Fprokopchuk1@xxxxxxxx/
> there were discussions about placing comments inside 'default' case.

For notifier functions in particular, yes. The config quoted above covers
more than those, though, if I'm not mistaken.

Jan