Re: [dpdk-dev] [PATCH] Make -Werror optional

[Panu Matilainen <pmatilai@redhat.com>]

On 02/23/2015 03:55 PM, Neil Horman wrote:
> On Mon, Feb 23, 2015 at 10:19:23AM +0200, Panu Matilainen wrote:
>> On 02/21/2015 09:33 PM, Neil Horman wrote:
>>> On Fri, Feb 20, 2015 at 05:55:21PM -0800, Stephen Hemminger wrote:
>>>> On Thu, 12 Feb 2015 16:54:44 +0200
>>>> Panu Matilainen <pmatilai@redhat.com> wrote:
>>>>
>>>>> On 02/12/2015 04:38 PM, Stephen Hemminger wrote:
>>>>>> On Thu, 12 Feb 2015 13:13:22 +0200
>>>>>> Panu Matilainen <pmatilai@redhat.com> wrote:
>>>>>>
>>>>>>> This adds new CONFIG_RTE_ERROR_ON_WARNING config option to enable
>>>>>>> fail-on-warning compile behavior, defaulting to off.
>>>>>>>
>>>>>>> Failing build on warnings is a useful developer tool but its bad
>>>>>>> for release tarballs which can and do get built with newer
>>>>>>> compilers than what was used/available during development. Compilers
>>>>>>> routinely add new warnings so code which built silently with cc X
>>>>>>> might no longer do so with X+1. This doesn't make the existing code
>>>>>>> any more buggier and failing the build in this case does not help
>>>>>>> not help improve code quality of an already released version either.
>>>>
>>>> Hopefully distro's like RHEL will build with -Werror enabled
>>>> and not allow build to go through with errors.
>>>>
>>> Thats usually what we do, yes.
>>
>> Um, nope. All Fedora and RHEL builds are done using a common base set of
>> flags set centrally from rpm configuration, and that includes among other
>> things -Wall but not -Werror, although since F21 -Werror=format-security is
>> included since that there are relatively few false positives for that.
>>
>> The thing is, compiler warnings from compilers are just that: warnings, and
>> often including hefty dose of false positives. A good package maintainer
>> will look at the build logs of his/her packages, investigate warnings and
>> send patches upstream to address them in oncoming versions where actually
>> relevant, but generally a package maintainer in a distro is not responsible
>> for achieving zero-warning build, nor should they.
>>
> Um, I don't know what you've been doing, but most of my packages typically have
> zero warnings.  Its true package maintainers have the option to disable
> warnings, and many do for pragmatic reasons as you note, but when its feasible,
> theres no reason not to make sure warning doesn't get raised when you expect
> there to be none.

The question wasn't about you or me or any other individual maintainer 
or package, it was whether distros build with -Werror, and the answer to 
that is generally no.

Individual maintainers are free to do so of course, but for example with 
the ubiquitous autoconf-based packages you cant just stick -Werror into 
CFLAGS because it breaks a whole pile of the autoconf tests.

But this is getting wildly off-topic for dpdk dev, I'll shut up now :)

	- Panu -