* rlp/rlpgen: remove build tag
This tag was supposed to prevent unstable output when types reference each other. Imagine
there are two struct types A and B, where a reference to type B is in A. If I run rlpgen
on type B first, and then on type A, the generator will see the B.EncodeRLP method and
call it. However, if I run rlpgen on type A first, it will inline the encoding of B.
The solution I chose for the initial release of rlpgen was to just ignore methods
generated by rlpgen using a build tag. But there is a problem with this: if any code in
the package calls EncodeRLP explicitly, the package can't be loaded without errors anymore
in rlpgen, because the loader ignores it. Would be nice if there was a way to just make it
ignore invalid functions during type checking (they're not necessary for rlpgen), but
golang.org/x/tools/go/packages does not provide a way of ignoring them.
Luckily, the types we use rlpgen with do not reference each other right now, so we can
just remove the build tags for now.
This enables the following linters
- typecheck
- unused
- staticcheck
- bidichk
- durationcheck
- exportloopref
- gosec
WIth a few exceptions.
- We use a deprecated protobuf in trezor. I didn't want to mess with that, since I cannot meaningfully test any changes there.
- The deprecated TypeMux is used in a few places still, so the warning for it is silenced for now.
- Using string type in context.WithValue is apparently wrong, one should use a custom type, to prevent collisions between different places in the hierarchy of callers. That should be fixed at some point, but may require some attention.
- The warnings for using weak random generator are squashed, since we use a lot of random without need for cryptographic guarantees.
This change adds a code generator tool for creating EncodeRLP method
implementations. The generated methods will behave identically to the
reflect-based encoder, but run faster because there is no reflection overhead.
Package rlp now provides the EncoderBuffer type for incremental encoding. This
is used by generated code, but the new methods can also be useful for
hand-written encoders.
There is also experimental support for generating DecodeRLP, and some new
methods have been added to the existing Stream type to support this. Creating
decoders with rlpgen is not recommended at this time because the generated
methods create very poor error reporting.
More detail about package rlp changes:
* rlp: externalize struct field processing / validation
This adds a new package, rlp/internal/rlpstruct, in preparation for the
RLP encoder generator.
I think the struct field rules are subtle enough to warrant extracting
this into their own package, even though it means that a bunch of
adapter code is needed for converting to/from rlpstruct.Type.
* rlp: add more decoder methods (for rlpgen)
This adds new methods on rlp.Stream:
- Uint64, Uint32, Uint16, Uint8, BigInt
- ReadBytes for decoding into []byte
- MoreDataInList - useful for optional list elements
* rlp: expose encoder buffer (for rlpgen)
This exposes the internal encoder buffer type for use in EncodeRLP
implementations.
The new EncoderBuffer type is a sort-of 'opaque handle' for a pointer to
encBuffer. It is implemented this way to ensure the global encBuffer pool
is handled correctly.
