Re: [libmicrohttpd] clang formatting discussion via [gnunet-developers]

[ng0]

Christian Grothoff transcribed 11K bytes:
> Dear MHD hackers,
> 
> There has been a (long-ish) discussion about using clang-format for
> source formatting among the GNUnet developers.  WDYT about applying the
> same/similar rules to GNU libmicrohttpd and also enforcing them via Git
> hooks on commit? I've attached the .clang-format file that resulted from
> the GNUnet discussion here.

Did you reach any consensus on this discussion here?
I'm already clang-formatting my code for lmhd but no
.clang-format exists in the repository.

If you require an entirely different style,
contributing to LibFormat and clang-format is an option.
I plant to do this with the outstanding KNF for NetBSD.

As far as I know we weren't 100% okay with the results
for gnunet but already use it.
 
> See in particular the following e-mails from the GNUnet discussion:
> 
> 
> On 4/15/19 10:02 AM, Schanzenbach, Martin wrote on [GNUnet-developers]:> Hi,
> >
> > FYI I added a clang-format at "contrib/conf/editors/clang-format".
> > Clang-format is usable with most editors (vim, emacs, vscode) with
> respective plugins.
> > This way, we can have a unified coding style.
> > Clang-format has a nice documentation and allows fine-grained setting
> which are also human readable:
> https://clang.llvm.org/docs/ClangFormatStyleOptions.html
> >
> > Let's use it and put it as a note into our coding guidelines?>
> 
> Martin also wrote:
> 
> > Most editors have plugins:
> >
> > emacs:
> https://llvm.org/svn/llvm-project/cfe/trunk/tools/clang-format/clang-format.el
> > (n)vim: https://github.com/rhysd/vim-clang-format
> > vscode: native
> > sublime: https://packagecontrol.io/packages/Clang%20Format
> 
> And most recently I wrote (latest point of the discussion):
> 
> >
> > Yes, the question is this: are there any developers here where their
> > editor cannot be reasonably integrated with clang-format? If so, please
> > do shout out now!
> >
> > I've so far heard only positive feedback for Martin's overall initiative
> > to get indentation under control, so for now I'll proceed with the
> > assumption that there are no blockers. But if you do have an issue with
> > this, please do let me know (on or off list) as soon as possible. If
> > there are no (sound) objections soon, I will give ng0/schanzen the
> > go-ahead to enable enforcement of clang formatting for all Git commits
> > in the future!
> >
> > Anyway, aside from the general policy debate, please read on for more
> > specific related issues.
> >
> > //// Deployment experience
> >
> > I had to install clang-format-9 from Debian experimental, as our
> > configuration includes options that are only in v9.
> >
> > For Emacs user's reference: Without v9, the Emacs integration silently
> > failed. I also had to create a symlink from clang-format to
> > clang-format-9, as the Emacs integration only looks for the clang-format
> > binary (and otherwise also fails silently).
> >
> >
> > Other than that, Emacs integration was straightforward:
> >
> > I added to gnunet/.dir-locals.el a hook on save (this may end up in Git
> > "soon")
> >
> >>>>
> > ((c-mode
> >   (eval add-hook 'before-save-hook #'clang-format-buffer nil t)))
> > <<<
> >
> >
> > and to .emacs the logic to find the clang-format package
> >
> >>>>
> > (require 'package)
> > (add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/";))
> > ;; initialize package system
> > (package-initialize)
> > ;; actually load the package
> > (require 'clang-format)
> > <<<
> >
> > And of course also installed the clang-format package (interactively,
> > M-x install-package) as per documentation from Martin's first link above.
> >
> > Finally, the clang-format style symlink must be set:
> >
> > # Install clang format symlink
> > ln -s contrib/conf/editors/clang-format .clang-format
> >
> > (this I will at to the bootstrap script).
> >
> >
> > //// Formatting gripes
> >
> > My remaining main issue with
> > https://clang.llvm.org/docs/ClangFormatStyleOptions.html
> > is that it cannot currently be forced to put a break after each argument
> > and each parameter, and it also cannot detect the exception that a
> > function has key-value pairs and thus should keep the arguments paired.
> >
> > However, the latter case is solvable! If we have key-value pairs, we
> can do:
> >
> > /* clang-format off */
> > fun (generalargs,
> >      key1, value1,
> >      key2, value2,
> >      key3, value3);
> > /* clang-format on */
> >
> > Real-world example from gnunet-gtk/src/namestore/gnunet-namestore-gtk.c:
> >
> >  /* clang-format off */
> >  gtk_tree_model_get (tm, &iter,
> >                      GNS_TREESTORE_COL_RECORD_TYPE, &n_type,
> >                      GNS_TREESTORE_COL_IS_PUBLIC, &n_public,
> >                      GNS_TREESTORE_COL_EXP_TIME, &n_exp_time,
> >                      GNS_TREESTORE_COL_EXP_TIME_IS_REL, &n_is_relative,
> >                      GNS_TREESTORE_COL_IS_SHADOW, &n_is_shadow,
> >                      GNS_TREESTORE_COL_VAL_AS_STR, &n_value,
> >                      -1);
> >  /* clang-format on */
> >
> > That way, clang-format won't touch the *nice* formatting. So if there is
> > a very strong reason, I would definitively approve turning off clang for
> > parts of the source.
> >
> > For this reason, please do NOT simply apply clang-format globally to
> > GNUnet.  Instead, when editing a file, do a quick check to see if
> > clang-format would destroy something that's just done "right", and *turn
> > it off* for those regions.  After that, a single commit with just the
> > clang-forward should be OK.
> >
> >
> > Happy hacking!
> >
> > Christian
> >
> 
> Please let me know what you think of this.
> 
> Happy hacking!
> 
> Christian

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