Some of the errors tests need to have their own schema, so the schema
can do something weird (or even be entirely invalid!). But most can
still share a schema. In this commit I have those indeed share a
schema, to avoid having to have a bunch of copies of mostly the same
schema. While doing so I noticed one error whose location wasn't very
useful, and fixed it.
Test plan: make check
GraphQL is pretty restrictive about its identifiers, so for the most
part we can and do safely use GraphQL identifiers in the Go we generate
with attention only to conflicts with other such identifiers. But we do
need to check one thing, which is that the identifier isn't a Go
keyword. (If it is, the generated code will almost certainly fail to
compile, but often with a confusing error message.) In this commit I add
such checks.
The most likely place to run into trouble here is argument names, which
are often one word and are used as-is. Operation names, if unexported,
can also be keywords, although in practice they're usually multiword.
Field names are always exported, thus safe. Generated type names are
always prefixed, camel-cased, with the operation name, so they always
contain an uppercase letter (even if the operation name is lowercase),
but type-names specified by `typename` may collide, so we check those.
In theory we could check type-names specified by `bind`, but these must
be defined by the user, so their code will already fail to compile, so I
didn't bother. I think that's all the places to consider, although it's
hard to be sure. In summary, we check argument names, operation names,
and user-specified type names.
Test plan: make check
