bitvec is primarily developed on the x86_64-unknown-linux-gnu,
x86_64-apple-darwin, and aarch64-unknown-linux-gnu targets. It is
tested for the other supported Rust targets using the cross-compile and
emulation tools available to us.
Because of the limitations in environmental awareness available to crates about their destination targets, there are some oddities that we currently are unable to detect or work around in source code, and instead merely tolerate in our processes.
On these targets, Serde does not define its traits on atomic types. However,
these targets do possess the atomic types, so the test suite errors when
attempting to assert that bitvec’s types (which do exist) implement the Serde
traits (which are gated on Serde’s own implementations).
Since rustc does not provide the precise target string as a #[cfg()] value,
these cannot be excluded in source code.
The ci/target_{test,check}_no_serde.txt files list all targets where Serde
disagrees with radium on atomic presence, and thus where our Serde
implementation tests cannot compile.
The ci/target_{test,check}_no_std.txt files list targets that either do not
have a standard library at all, or where the standard library is insufficient to
operate the test suite (notably, certain WASM targets are unsupported by rand,
so the test suite cannot produce random data on them).
The ci/target_check_*.txt files do not have Cross images available where the
test suite can be executed as a target program. As such, we can only check that
bitvec builds correctly for these targets, but we cannot emulate them to
execute the tests directly.
In general, this is considered acceptable, as bitvec has no logic that is
strongly dependent on the precise target that is not already covered by the
distribution’s own infrastructure.
However, we still strive to run the test suite on every target possible, and
should promote targets from _check_ to _test_ if Cross gains support for
them.