Currently `bitcoin` cannot be built with no features enabled, it must
have either "no-std" or "std" enabled. This is an artifact from when
we depended on `core2` for "no-std", now that we have our own `io` crate
and we unconditionally depend on it we can remove the "no-std" feature.
In order to support standard (de)serialization of structs, the
`rust-bitcoin` ecosystem uses the standard `std::io::{Read,Write}`
traits. This works great for environments with `std`, however sadly
the `std::io` module has not yet been added to the `core` crate.
Thus, in `no-std`, the `rust-bitcoin` ecosystem has historically
used the `core2` crate to provide copies of the `std::io` module
without any major dependencies. Sadly, its one dependency,
`memchr`, recently broke our MSRV.
Worse, because we didn't want to take on any excess dependencies
for `std` builds, `rust-bitcoin` has had to have
mutually-exclusive `std` and `no-std` builds. This breaks general
assumptions about how features work in Rust, causing substantial
pain for applications far downstream of `rust-bitcoin` crates.
Here, we add a new `bitcoin_io` crate, making it an unconditional
dependency and using its `io` module in the in-repository crates
in place of `std::io` and `core2::io`. As it is not substantial
additional code, the `hashes` io implementations are no longer
feature-gated.
This doesn't actually accomplish anything on its own, only adding
the new crate which still depends on `core2`.
In order to keep the embedded and schemacs test crates building when we
update their local transient dependencies we need to use a `patch`
section.
- For `bitcoin/embedded` add `patch` section for `internals`, `hashes`
already has an entry.
- For `hashes/embedded` add `patch` section for `internals`.
- For `hashes/extendend_tests/schemars` add `patch` section for
`internals`.
FTR for direct local dependencies we use a `path` field when specifying
the dependency.
This patches `bitcoin_hashes` to use the version in the repository and
fixes the code after removal of `Deref`.
This also turns off `AS_DEPENDENCY` check with the intention to refactor
it later.
Currently we implement `Deref` for hashes. From the docs [0]
> Deref should only be implemented for smart pointers to avoid confusion
Furthermore because we implement `Deref` as well as implement
`internals::hex::display::DisplayHex` for slices hashes get coerced into
slices and `to_lower_hex_string` can be called on them, this is
incorrect because `DisplayHex` does not account for hashes that display
backwards so we end up with the wrong string.
[0] https://doc.rust-lang.org/std/ops/trait.Deref.html
We would like to bring the `bitcoin_hashes` crate into the
`rust-bitcoin` repository.
Import `bitcoin_hashes` into `rust-bitocin/hashes`, doing so looses all
the commit history from the original crate but if we archive the
original repository then the history will be preserved. We maintain the
same version number obviously and in the changelog we note the change of
repository.
Commit hash that was tip of `bitcoin_hashes` at time of import:
commit 54c16249e06cc6b7870c7fc07d90f489d82647c7
Includes making `embedded` and `fuzzing` per-crate i.e., move them into
`bitcoin` as hashes includes these also.
NOTE: Does _not_ enable fuzzing for `hashes` in CI.
Notes on CI:
Attempts to merge in the github actions from the hashes crate however reduces
coverage by not running hashes tests for beta toolchain. Some additional
work could be done to improve the CI to increase efficiency without
reducing coverage. Leaving for another day.
Tobin C. Harding
Matt Corallo
Martin Habovstiak