fiat backend MSRV is 1.57.0

[pinkforest]

When testing cfg(curve25519_dalek_serial) addressing #437

foobar@foobar-MS-7C77:~/cc/curve25519-dalek$ env RUSTFLAGS="--cfg curve25519_dalek_serial="fiat"" cargo test

error: package `os_str_bytes v6.4.1` cannot be built because it requires rustc 1.57.0 or newer, while the currently active rustc version is 1.56.1

[tarcieri]

That appears to be unrelated to fiat-crypto which has no dependencies

For starters, --cfg curve25519_dalek_serial="fiat" is not the correct name for the cfg directive (and this is a good example of a downside of using cfg, namely we get no checks for invalid cfg attributes). It should be curve25519_dalek_backend="fiat". nm, I guess you were trying to add that in #463

os_str_bytes is being pulled in as:

dev-dependencies -> criterion -> clap v3 -> clap_lex -> os_str_bytes

...so this should only affect the MSRV when running cargo test, not the MSRV of the overall crate.

We also use -Z minimal-versions to test MSRV.

[pinkforest]

Ah that makes sense, closing.

[pinkforest]

We also use -Z minimal-versions to test MSRV.

CI still hardcodes 1.56.1 - -Z minimal is only used for getting the Cargo.lock w/ nightly ?

It doesn't actually test MSRV .. maybe it should ? -Z minimal-versions was stabilised in 1.56 me thinks ?

    # First run `cargo +nightly -Z minimal-verisons check` in order to get a
    # Cargo.lock with the oldest possible deps
    - uses: dtolnay/rust-toolchain@nightly
    - run: cargo -Z minimal-versions check --no-default-features --features serde
    # Now check that `cargo build` works with respect to the oldest possible
    # deps and the stated MSRV
    - uses: dtolnay/[email protected]
    - run: cargo build --no-default-features --features serde

[tarcieri]

These parts of the job:

 - uses: dtolnay/[email protected]
 - run: cargo build --no-default-features --features serde

...check that it builds successfully with 1.56.1, the advertised MSRV.

[pinkforest]

yes - build yes but not test plus 1.56.1 is hardcoded there - I always wondered how to avoid hardcoding it in CI :)

[tarcieri]

Aah, yeah it should probably test MSRV.

That’s easy enough to do by adding MSRV and stable to the test matrix.