On Thu, Sep 01, 2022 at 12:55:36PM +0100, Alex Bennée wrote: > > "Wang, Lei" <lei4.w...@intel.com> writes: > > > On 9/1/2022 4:12 PM, Daniel P. Berrangé wrote: > >> On Thu, Sep 01, 2022 at 09:08:33AM +0800, Wang, Lei wrote: > >>> On 8/31/2022 6:39 PM, Daniel P. Berrangé wrote: > >>>> On Wed, Aug 31, 2022 at 05:18:34PM +0800, Wang, Lei wrote: > >>>>> > >>>>> > >>>>> On 8/31/2022 4:49 PM, Daniel P. Berrangé wrote: > >>>>>> On Wed, Aug 31, 2022 at 02:23:51PM +0800, Wang, Lei wrote: > >>>>>>> > >>>>>>> On 10/2/2015 1:30 AM, marcandre.lur...@redhat.com wrote: > >>>>>>>> From: Marc-André Lureau <marcandre.lur...@redhat.com> > >>>>>>>> > >>>>>>>> clang-format is awesome to reflow your code according to qemu coding > >>>>>>>> style in an editor (in the region you modify). > >>>>>>>> > >>>>>>>> (note: clang-tidy should be able to add missing braces around > >>>>>>>> statements, but I haven't tried it, it's quite recent) > >>>>>>>> > >>>>>>>> Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> > >>>>>>>> --- > >>>>>>>> .clang-format | 6 ++++++ > >>>>>>>> 1 file changed, 6 insertions(+) > >>>>>>>> create mode 100644 .clang-format > >>>>>>>> > >>>>>>>> diff --git a/.clang-format b/.clang-format > >>>>>>>> new file mode 100644 > >>>>>>>> index 0000000..6422547 > >>>>>>>> --- /dev/null > >>>>>>>> +++ b/.clang-format > >>>>>>>> @@ -0,0 +1,6 @@ > >>>>>>>> +BasedOnStyle: LLVM > >>>>>>>> +IndentWidth: 4 > >>>>>>>> +UseTab: Never > >>>>>>>> +BreakBeforeBraces: Linux > >>>>>>>> +AllowShortIfStatementsOnASingleLine: false > >>>>>>>> +IndentCaseLabels: false > >>>>>>> > >>>>>>> Hi, any progress on this? I also found a gist on GitHub which can be a > >>>>>>> reference: > >>>>>>> https://gist.github.com/elmarco/aa5e0b23567f46fb7f0e73cde586a0c1 > >>>>>> > >>>>>> clang-format is a great tool and I'd highly recommend its use on > >>>>>> any newly started projects, and even retrospectively on existing > >>>>>> projects which are small scale. Adding it to large existing projects > >>>>>> is problematic though. > >>>>>> > >>>>>> None of the QEMU code complies with it today and indeed there is > >>>>>> quite a bit of style variance across different parts of QEMU. If > >>>>>> we add this config file, and someone makes a 1 line change in a > >>>>>> file, clang-format will reformat the entire file contents. > >>>>>> > >>>>>> The only practical way to introduce use of clang-format would be > >>>>>> to do a bulk reformat of the entire codebase. That is something > >>>>>> that is quite disruptive to both people with patches they're > >>>>>> working on but not submitted yet, as well as people wanting to > >>>>>> cherry-pick new commits back to old code branches. > >>>>>> > >>>>>> With regards, > >>>>>> Daniel > >>>>> > >>>>> I think the benefits of introducing clang-format mainly for its ability > >>>>> to > >>>>> format a code range, which means for any future contributions, we could > >>>>> encourage a range format before the patch is generated. This can > >>>>> extensively > >>>>> simplify my workflow, especially because I use the Neovim + LSP > >>>>> combination, > >>>>> which supports a built-in function "lua vim.lsp.buf.range_formatting()". > >>>> > >>>> IMHO partial format conversions are even worse than full conversions, > >>>> because they would make code inconsistent within the scope of a file. > >>> > >>> So you mean when we're adding new code in an old file, the coding style > >>> should also be the old one? That sounds a bit unreasonable. I thought we > >>> are > >>> shifting the coding style in an on-demand way, so we can finally achieve > >>> to > >>> the new style mildly, if each time we're using the old coding style, that > >>> could be impossible. > >> > >> From my POV as a maintainer, the best situation would be consistency across > >> the entire codebase. Since we likely won't get that though, then next best > >> is consistency across the subsystem directory, and next best is consistency > >> across the whole file. Mixing code styles within a file is the worst IMHO. > >> > >>> > >>>>> I have no interest in reformatting the existing code and also think > >>>>> using it > >>>>> to reformat an entire file shouldn't be encouraged, but, we can leverage > >>>>> this tool to give future contributions a better experience. It's also > >>>>> important to note that the kernel already has a ".clang-format" file, > >>>>> so I > >>>>> think we can give it a try:) > >>>> > >>>> The mere action of introducing a .clang-format file in the root of the > >>>> repository will cause some contributors' editors to automatically > >>>> reformat files every time they are saved. IOW even if you don't want > >>>> intend to do reformatting, that will be a net result. > >>> > >>> I think that depends on developer's configuration, as far as I know, > >>> format > >>> on save is a feature which can be easily disabled on most of the IDE's, > >>> such > >>> as VSCode. > >> > >> You could disable it, but it requires each developer to know that we're > >> shipping a clang-format that should not in fact be used to reformat > >> code, which is rather counterintuitive. > >> > >> With regards, > >> Daniel > > > > OK, your POV makes sense too. I think we can do a tradeoff, for an example, > > we > > can add an officially suggested ".clang-format" file in the documentation, > > so it > > won't confuse the developers who have no interest in the clang stuffs, and > > it > > will also be more convenient for the developers who don't want to check the > > coding style manually each time before they're submitting a patch. > > For most editors we already have a .editorconfig but it looks like there > is no integration for clang-format there. We could put a file in > contrib/style/ for an explicit call: > > clang-format -style=contrib/style/clang.format > > I suspect we should move the .dir-locals there to given Emacs users > should be able to use the .editorconfig and it reduces duplication.
I'd be against that on the basis that EditorConfig support is an add-on for emacs which we can't be sure our contributors will have installed. The .dir-locals ensures we get sensible behaviour from all emacs users by default. > And of course mention the location of these style linters in > docs/devel/style.rst Note clang-format is not a style linter - it is a bulk code reformatter that does waaaaaaay more than the .editorconfig or .dir-locals does - our code is largely compliant with the .editorconfig/.dir-locals rules, so it is good that we ensure continued compliance by default. clang-format is a completely different situation as essentially none of our code will be compliant today. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|