Re: Coding Style Review and Automation

["Roger Pau Monné" <roger.pau@citrix.com>]

On Tue, Feb 11, 2025 at 11:19:23AM +0100, Jan Beulich wrote:
> On 11.02.2025 10:10, Luca Fancellu wrote:
> >>> 3) The size of the patch after applying clang-format is huge. Really. Something
> >>> like 9 MB. Even if everyone agrees that the approach is good and we can proceed
> >>> with it, it is highly unlikely anyone will be able to review it. Considering
> >>> that new patches are being added to the upstream during such a review, it may
> >>> also lead to new code style violations or require a new review of that huge
> >>> patch.
> >>
> >> I think this approach is difficult.  It would likely introduce a lot
> >> of noise when using `git blame` (I know, it's just one extra jump,
> >> but...), plus would likely break every patch that we currently have
> >> in-flight.
> > 
> > I think we already discussed this in the past and having some churn was accepted,
> > also about breaking existing patches, every change merged has the potential to do
> > that, this one is more likely but it’s the game I guess?
> 
> That's easy to say if you have just a few patches in flight, yet I'm worried
> about this when considering the hundreds of mine that are awaiting review.

There are also downstreams (including distros) with varying length of
patch queues on top of Xen.  Arguably they have to rebase the queue
every time they update, but a wide change in coding style will likely
be fairly disruptive to them.

Don't take this as a reason to reject clang-format.  As mentioned
elsewhere I think the format supported by clang-format would need to
be fairly similar to the current Xen one (up to the point that chunks
of code using the new and the old style could live together).  Then we
would enforce it only for newly added chunks of code initially IMO.

Thanks, Roger.