Re: [dpdk-dev] tools brainstorming

[Neil Horman <nhorman@tuxdriver.com>]

On Thu, Apr 09, 2015 at 09:10:19PM +0000, Wiles, Keith wrote:
> 
> 
> On 4/9/15, 2:38 PM, "Jay Rolette" <rolette@infiniteio.com> wrote:
> 
> >On Thu, Apr 9, 2015 at 2:16 PM, Neil Horman <nhorman@tuxdriver.com> wrote:
> >
> >> On Thu, Apr 09, 2015 at 11:31:39AM -0500, Jay Rolette wrote:
> >> > On Wed, Apr 8, 2015 at 5:38 PM, Stephen Hemminger <
> >> > stephen@networkplumber.org> wrote:
> >> >
> >> > > On Wed, 8 Apr 2015 16:29:54 -0600
> >> > > Jay Rolette <rolette@infiniteio.com> wrote:
> >> > >
> >> > > > "C comments" includes //, right? It's been part of the C standard
> >> for a
> >> > > long time now...
> >> > >
> >> > > Yes but.
> >> > > I like to use checkpatch and checkpatch enforces kernel style which
> >> does
> >> > > not allow // for
> >> > > comments.
> >> > >
> >> >
> >> > Fork checkpatch and disable that bit? DPDK isn't the kernel, so no
> >> > requirement to follow all of its rules
> >> >
> >>
> >> Doesn't that beg the question, why?  I understand the DPDK isn't the
> >> kernel, but
> >> we're not talking about clarity of code, not anything functional to that
> >> code.
> >> It seems we would be better served by just taking something that works
> >>here
> >> rather than re-inventing the wheel and digging into the minuate of what
> >> type of
> >> comments should be allowed (unless there is a compelling reason to
> >>change
> >> it
> >> that supercedes the avilable tools).  If not checkpath, then some other
> >> tool,
> >> but It seems to me that coding style is one of those things where we can
> >> bend to
> >> the tool rather than taking the time to make the tool do exactly whats
> >> desired,
> >> at least until someone gets the time to modify it.
> >>
> >
> >Fair question.
> >
> >It depends a bit on how much you want to encourage patch contributions. Is
> >it worth adding more pain for folks trying to contribute patches for
> >things
> >like this?
> >
> >Should we force someone to spend time redoing a patch because of which way
> >they do their parenthesis? What about number of spaces to indent code? //
> >vs /* */ comments? None of these matter functionally and they don't affect
> >maintenance generally.
> >
> >If someone is modifying existing code, then yeah, they should follow the
> >prevailing style (indention level, brace alignment, etc.) of the file they
> >are in. It helps readability, which makes maintenance easier. However,
> >IMO,
> >mixing // and /* */ for comments doesn't affect the readability of the
> >source.
> >
> >I know if I submit a patch and the only feedback is that I should have
> >used
> >/* */ for comments, I'm extremely unlikely spend extra time to resubmit
> >the
> >patch for pedantry.
> 
> I looked at checkpatch.pl for few minutes and the code does check for C99
> comments and adding a command line option to allow C99 comments could
> pretty simple. I found the code around line 3048 or search for C99, it is
> possible it could accepted back into Linux as long as the default option
> was to not allow C99 comments.
> 
> Allowing C99 comments would be nice and the only problem I could see if
> some compiler has a problem with them. I believe all of the compilers we
> support allow C99 comments.
> 
> The only other reason to allow them is if we add some open source code in
> the future to DPDK which has C99 comments and if would be a pain to have
> to convert that code every time the open source group released a new
> version. It does open that path IMO.
> 

So, this again seems to be bad philosophy in my mind.  If we are, to use your
exmple, accept code into the DPDK in the future with comments that violate our
selected style, it is then, by definition, in violation of the style guidelines.
If we accept it anyway, or if we allow both styles (by documenting it/codifying
it a tool to check for/etc) then we dilute the style guide.  Maybe in some
cases, such as this, thats ok, but its something to be cogniscent of.
Especially if making the choice to allow both put us in a position of having to
maintain a tool to do the checking, then I think we need to fall on the side of
going with what the tool (checkpatch or something else) does, unless we have a
maintainer stepping up.

The bottom line is that style guides enforce style, and tooling makes
contributors condusive to following the style.  If we have someone that is
willing to maintain such a tool, then we have a lot of leway in what the style
is, but if we don't then we really need to follow the style that an existing
tool provides, because without tooling, contributors aren't likely to bother
with strict adherence to the style.

Neil