Hi Jeremy, The `Which` enums are intentionally not `enum class` because I wanted the enumerants to appear as constants in the containing class, as this enum actually represents the union tags for the containing class, so the `Which` part is sort of superfluous. All other enums, though, are declared as `enum class`. This is all to say, the API was intentionally designed this way.
In any case, we definitely can't change the way `Which` enums are generated as doing so would break most users of Cap'n Proto (they'd have to update their code to match), which is unreasonable. Note that there is no actual problem created by the shadowing here. The problem the warning is worried about would be for code inside of `Type::AnyPointer::Unconstrained` -- if it wanted to refer to e.g. `Type::STRUCT`, it would have to include the `Type::` prefix, as just `STRUCT` would refer to `Type::AnyPointer::Unconstrained::STRUCT`. But all code inside the scope of `Type::AnyPointer::Unconstrained` is generated code anyway, and the code generator will never get it wrong. External human-written code that uses the API always has to use qualification anyway, so also won't get it wrong. Probably the right answer would be for us to add CAPNP_BEGIN_HEADER and CAPNP_END_HEADER around generated .capnp.h headers. This would disable all warnings within the header unless you are compiling Cap'n Proto itself. All of the hand-written capnp header files do this already, but schema.capnp.h is generated code. If we update the code generator, then all .capnp.h generated files will disable warnings, but that's probably reasonable since if you're not working on Cap'n Proto itself, there's probably nothing you can do about such warnings anyway, since you can't modify generated code. Anyway, I'd accept a PR which modifies the code generator to wrap headers in CAPNP_BEGIN_HEADER/CAPNP_END_HEADER. -Kenton On Mon, Sep 14, 2020 at 4:41 PM Jeremy Steward <jer...@occipital.com> wrote: > Hi Kenton / to whom it may concern! > > I’m using capnproto and when I try to use the library I seem to be getting > the following errors from schema.capnp.h. They seem related to the “Which” > enum with -Wshadow -Werror. > > > In file included from > ../../../../../../ext/capnproto/c++/src/capnp/dynamic.h:35: > In file included from > ../../../../../../ext/capnproto/c++/src/capnp/schema.h:39: > ../../../../../../ext/capnproto/c++/src/capnp/schema.capnp.h:488:5: error: > declaration shadows a static data member of 'capnp::schema::Type' > [-Werror,-Wshadow] > STRUCT, > ^ > ../../../../../../ext/capnproto/c++/src/capnp/schema.capnp.h:379:5: note: > previous declaration is here > STRUCT, > ^ > ../../../../../../ext/capnproto/c++/src/capnp/schema.capnp.h:489:5: error: > declaration shadows a static data member of 'capnp::schema::Type' > [-Werror,-Wshadow] > LIST, > ^ > ../../../../../../ext/capnproto/c++/src/capnp/schema.capnp.h:377:5: note: > previous declaration is here > LIST, > ^ > > I think this is because these “Which” enums are declared as “enum” and not > “enum class.” I think this may be unavoidable as long as I’m on the 0.8 > release version (unless I want to make local edits, which frankly I’m not > excited to do), so I may have to do -Wno-error=shadow. However, I was > wondering if in future versions it would be possible to fix this so that > Type::AnyPointer::Unconstrained::Which can be of type “enum class” instead > of just a pure “enum.” Would there be any problem with this? Am I > misunderstanding something? It seems like the project uses C++11/14 in a > number of places already, so this is probably not the biggest deal? > > Cheers, > — > Jeremy Steward, M.Sc, E.I.T. > Senior Software Engineer > Technical Leader - Calibration > Occipital Inc. > +1 (303) 815-4240 > > -- > You received this message because you are subscribed to the Google Groups > "Cap'n Proto" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to capnproto+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/capnproto/5D0D8A68-3EB3-4590-96D5-04065FE4E160%40occipital.com > <https://groups.google.com/d/msgid/capnproto/5D0D8A68-3EB3-4590-96D5-04065FE4E160%40occipital.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Cap'n Proto" group. To unsubscribe from this group and stop receiving emails from it, send an email to capnproto+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/capnproto/CAJouXQ%3Dt34LZoC%2BruRiEH36NPicSWzB0bEu1O%3DHMuvkRfT203g%40mail.gmail.com.
