[cfe-dev] Paragraph numbers in C++ tests

[via cfe-dev]

> -----Original Message-----
> From: cfe-dev [mailto:cfe-dev-bounces at lists.llvm.org] On Behalf Of Bruno
> Ricci via cfe-dev
> Sent: Tuesday, April 30, 2019 10:34 AM
> To: cfe-dev at lists.llvm.org
> Subject: Re: [cfe-dev] Paragraph numbers in C++ tests
> 
> 
> 
> On 29/04/2019 19:33, David Blaikie wrote:
> > Even if they're updated to reflect current paragraph numbers, they'd
> > still fall into disrepair in future standards & be hard to know which
> > version they applied to. So I'd support adding C++ version numbers to
> > them. At least on principle - but the reality/situations they're used
> > in might make that awkward/problematic, I don't know.
> 
> I was thinking about the naming of tests for sections of the C++ standard.
> For example the tests for [namespace.udecl] are:
>   p1.cpp
>   p3.cpp
>   p4.cpp
>   p5-cxx0x.cpp
>   p6-cxx11.cpp
>   p7.cpp
>   p8.cpp
>   p8-cxx0x.cpp
>   p10.cpp
>   p11.cpp
>   p12.cpp
>   p13.cpp
>   p15.cpp
>   p18.cpp
> 
> I think that naming the tests pn-cxxmm.cpp to mean, "paragraph pn of
> cxxmm"
> is reasonable, with the understanding that naming a test p3-cxx17.cpp does
> not
> mean that the corresponding rule is specific to C++17, just that it was
> written
> against C++17.
> 
> Bruno

The real issue is, "p3" in C++11 might be renumbered "p4" in C++14 
and "p5" in C++17 and ...  so what does "p3.cpp" actually test?  
You can't tell just from the name of the file because the name's
meaning is context-sensitive.

Intuitively I'd think "p3-cxx11.cpp" means "tests p3 as it existed in
the C++11 standard" and whether that paragraph is still p3 in later
editions is an exercise for the reader.

I recommend, give up on naming tests after paragraph numbers, because
they aren't actually meaningful.
--paulr

> 
> >
> > On Mon, Apr 29, 2019 at 7:28 AM Bruno Ricci via cfe-dev
> > <cfe-dev at lists.llvm.org> wrote:
> >>
> >> Hi,
> >>
> >> An annoying part of writing tests for C++ is that the paragraph numbers
> are not
> >> stable between versions of the standard. Is there an accepted way to
> deal with
> >> this issue ? I can imagine several ways to deal with this:
> >>   - Rename the tests so that they match the latest standard/draft.
> >>   - Add a suffix/prefix with the version for the paragraph number.
> >>   - ... ?
> >>
> >> Bruno
> >> _______________________________________________
> >> cfe-dev mailing list
> >> cfe-dev at lists.llvm.org
> >> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
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