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

[Darshit Shah]

This is a good idea and as Tim also mentioned, is something I've been trying to
get for GNU Wget2 as well.

However, with regards to clang format, one complaint I've heard from another
project is that it is quite sensitive to the specific version of the binary.
I don't have first hand experience, but from what I hear, even with the same
config file, different versions of clang-format may result in slightly
different outputs which can get annoying very quickly.

The problem with GNU Indent is that it doesn't seem to be as versatile as
clang-format and doesn't have the convenient editor plugins either.

* Christian Grothoff <address@hidden> [190418 14:42]:
> 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.
> 
> 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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-- 
Thanking You,
Darshit Shah
PGP Fingerprint: 7845 120B 07CB D8D6 ECE5 FF2B 2A17 43ED A91A 35B6

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