Re: [cocci] behavior change in semantic patches since c36b51ffc889 …

[Jacob Keller <jacob.e.keller@intel.com>]

On 3/8/2025 12:39 AM, Markus Elfring wrote:
>> I tried this out and it does seem to fix the white spacing for our
>> particular cases.
> 
> Thanks for such positive feedback.
> 
> Will your development interests grow also for further SmPL code variations?
> 
> 
>> From here, I just repeated the process until git bisect told me which
>> commit had the breaking change.
> 
> How many iterations did you need to try out here?
> 

About a dozen. Bisection is powerful because it scales with the
logarithm of the number of commits.

> 
>> There were a couple gotchas where the checked out commit didn't compile
>> but I managed to figure out which changes were needed and manually
>> pulled those in each time.
> 
> Do you see chances to improve such a process anyhow?
> 

Most projects which use bisect heavily try to ensure that at least
compilation works with every change committed. This ensures that you can
build the project at any arbitrary commit in order to use the bisect
process.

>>                            One option would be to run a style formatting
>> tool after transforms, to allow a tool dedicated to code formatting vs
>> trying to make spatch and coccinelle do everything these can do.
> 
> Are you looking for ways to avoid extra efforts for code reformatting?
> 

In my experience, our existing coding style is not 100% replicated in
any of the formatting tools. It would take a significant effort to get
to the point where we could run a formatting tool without completely
re-formatting the entire code base.

> 
>> I do think improvements in the way you can specify spacing would be
>> useful but may complicate the already difficult syntax of semantic patches.
> Adhering to code style requirements can be challenging.
> 

Yep. I'm ok with some compromises, and we often have accepted those in
the past when adding new semantic patches.

However, this particular case is a change in the behavior of spatch,
which is a bit more difficult for us.

> Regards,
> Markus