[PATCH] D13368: [clang-tidy] add check cppcoreguidelines-pro-type-static-cast-downcast

[Aaron Ballman via cfe-commits]

On Tue, Oct 6, 2015 at 10:15 AM, Manuel Klimek <klimek at google.com> wrote:
> On Tue, Oct 6, 2015 at 4:12 PM Aaron Ballman <aaron.ballman at gmail.com>
> wrote:
>>
>> aaron.ballman added a comment.
>>
>> In http://reviews.llvm.org/D13368#260672, @klimek wrote:
>>
>> > In http://reviews.llvm.org/D13368#260669, @aaron.ballman wrote:
>> >
>> > > This wasn't a comment on the rule so much as a comment on the
>> > > diagnostic not being very helpful.In this case, you're telling the user to
>> > > not do something, but it is unclear how the user would structure their code
>> > > to silence this diagnostic. Perhaps there is no way to word this to give the
>> > > user a clue, but we should at least try. If I got this diagnostic as it is
>> > > now, I would scratch my head and quickly decide to ignore it.
>> >
>> >
>> > The cpp core guidelines are written in a way that they should be
>> > referenceable by links - do we want to add links to the relevant portions of
>> > the core guidelines from the clang-tidy checks?
>>
>>
>> I'd be hesitant to do that. It would add a lot of verbiage to diagnostics
>> that are likely to be chatty, and if the links ever go dead mid-release
>> cycle for us, we're stuck looking bad with no way to fix it. CERT's
>> guidelines are also linkable in the same fashion (as would be hypothetical
>> checks for MISRA, JSF, etc), and I would have the same hesitation for those
>> as well due to the potential dead link issue.
>>
>> I think that having the links within the user-facing documentation is a
>> must-have though (and something we've been pretty good about thus far)
>> because those can be updated live from ToT. So perhaps a permanent short
>> link to our own documentation might be useful (if a bit obtuse since our
>> docs mostly just point to other docs elsewhere)? I'd still be a bit worried
>> about expired short links or something, but maybe we already host a service
>> for this sort of thing?
>
>
> I'll postulate that a) github will not go away anytime soon and b) github
> will have a hard time changing their link structure so linking into revision
> N in branch M doesn't work any more.
> Thus, I think if we link into the github release of the core guildelines,
> we'll be fine.

Github's structure and stability isn't what I'm worried about. The C++
Core Guidelines internal structure is what I am worried about. They
currently use anchors to navigate around CppCoreGuidelines.md, and
those anchor names may or may not be stable. Even with the best of
intentions on stability, links change.

~Aaron