Re: [PATCH v5 1/2] check-uapi: Introduce check-uapi.sh

[John Moon]

On 4/11/2023 11:14 PM, Greg Kroah-Hartman wrote:
> > Would you find the tool more useful if it simply filtered out all instances
> > where the size of the type did not change? This would filter out the
> > following which the tool currently flags:
> >
> > - enum expansions
> > - reserved field expansions
> > - expansions of a struct with a flex array at the end
> > - type changes
> > - re-ordering of existing members
> > - ...others?
>
> Obviously not, as some of those are real breakages, and some are not at
> all.
>
> Please understand what is an abi breakage.  Adding new enums is not.
> Using a reserved field is not.  Reording existing members IS.

Yes, understood that method would miss certain classes of breakages. I 
was suggesting it as a way to improve the signal-to-noise ratio of the 
tool since we don't currently have an algorithm for determining 
breakages with 100% accuracy.

We'll work internally and with the libabigail team to improve the story 
here and get back to you. Thanks for the discussion!

- John