Allow windows-sys 0.61 without MSRV bump

[hanna-kruppe]

Several anstream crates currently require windows-sys 0.60.2 and don't allow 0.61 or newer. The 0.60 -> 0.61 bump is different from other bumps because 0.61 is the first version that uses the raw-dylib feature to have rustc generate the import library, instead of pulling in large pre-compiled import libraries via windows-targets. Usually people care more about avoiding multiple windows-sys versions and are happy to stay on older versions to achieve this, but now there's tangible advantages to preferring the newer version (avoiding pre-built blobs, smaller download size and vendor directory).

Bumping the windows-sys requirement from ^0.60.2 to ^0.61 would break MSRV (as discussed in #276). If this was just a matter of waiting N months until MSRV becomes 1.71 automatically, I'd just wait. But since there's no clear timeline, I don't want to wait indefinitely. For dependencies that are replaced by new std features, this is addressed by "polyfill" crates, but that doesn't seem applicable here.

Allowing both windows-sys 0.60 and 0.61 would resolve this without having to bump MSRV. Several other libraries with MSRV < 1.71 already do this (rustix, errno, tempfile, nu-ansi-term, is-terminal, os_pipe, jiff, ...). Allowing both 0.52 and 0.59 was previously rejected in #238 and I understand the reasons @epage gave. However, I think the trade-off is significantly different for 0.60 and 0.61:

• Due to MSRV, "just" updating to 0.61 and not supporting older versions is not an option for the foreseeable future (I'd be happy to be proven wrong about this)
• Staying on 0.60 only imposes a tangible cost on dependents with higher MSRV
• The only change in 0.61 is the switch to windows-link. That's only a breaking change for esoteric reasons which don't affect anstream. As long as there's nothing taking function pointers of windows-sys functions and expecting them to have a specific ABI string, there's no need to delicately avoid stepping on API differences between the two versions.

[epage]

Stepping through some thoughts.

Our windows code at this point is relatively low touch.

We will have compilation or even test coverage for 3 versions (see below). We likely don't need coverage for everything between those.

The main thing lacking in that coverage is there isn't a guarantee we are cover the full range of the version requirement. We also don't test the latest version for PRs.

RenovateBot will just keep updating the upper bound and will be easy to overlook it, so this isn't as much about this version but about doing this for all future breaking changes going forward.

---

the oldest version possible

anstyle/.github/workflows/ci.yml

Lines 75 to 92 in 1d13dd2

	minimal-versions:
	name: Minimal versions
	runs-on: ubuntu-latest
	steps:
	- name: Checkout repository
	uses: actions/checkout@v5
	- name: Install stable Rust
	uses: dtolnay/rust-toolchain@stable
	with:
	toolchain: stable
	- name: Install nightly Rust
	uses: dtolnay/rust-toolchain@stable
	with:
	toolchain: nightly
	- name: Downgrade dependencies to minimal versions
	run: cargo +nightly generate-lockfile -Z minimal-versions
	- name: Compile with minimal versions
	run: cargo +stable check --workspace --all-features --locked --keep-going

the latest version compatible with our MSRV

anstyle/.github/workflows/ci.yml

Lines 33 to 57 in 1d13dd2

	test:
	name: Test
	strategy:
	matrix:
	os: ["ubuntu-latest", "windows-latest", "macos-latest"]
	rust: ["stable"]
	continue-on-error: ${{ matrix.rust != 'stable' }}
	runs-on: ${{ matrix.os }}
	env:
	# Reduce amount of data cached
	CARGO_PROFILE_DEV_DEBUG: line-tables-only
	steps:
	- name: Checkout repository
	uses: actions/checkout@v5
	- name: Install Rust
	uses: dtolnay/rust-toolchain@stable
	with:
	toolchain: ${{ matrix.rust }}
	components: rustfmt
	- uses: Swatinem/rust-cache@v2
	- uses: taiki-e/install-action@cargo-hack
	- name: Build
	run: cargo test --workspace --no-run
	- name: Test
	run: cargo hack test --each-feature --workspace

the latest version (only runs on master and not PRs)

anstyle/.github/workflows/rust-next.yml

Lines 48 to 66 in 1d13dd2

	latest:
	name: "Check latest dependencies"
	runs-on: ubuntu-latest
	steps:
	- name: Checkout repository
	uses: actions/checkout@v5
	- name: Install Rust
	uses: dtolnay/rust-toolchain@stable
	with:
	toolchain: stable
	components: rustfmt
	- uses: Swatinem/rust-cache@v2
	- uses: taiki-e/install-action@cargo-hack
	- name: Update dependencies
	run: cargo update
	- name: Build
	run: cargo test --workspace --no-run
	- name: Test
	run: cargo hack test --each-feature --workspace

[epage]

I was hoping we could recommend a windows-only job that ran cargo update windows but we still have a couple versions in our dependency tree because we depend on an old version of clap.

Oh well.

Let's go ahead and move forward with the dependency version requirement change for now. We can always adjust as needed.

[hanna-kruppe]

I suspect that the CI coverage won't work out that favorably: the minimal-versions job and the "run cargo update first" job only run on Ubuntu right now, and the MSRV-aware resolver doesn't explore multi-major-version ranges. But I'll create a PR and then we'll see what PR CI actually ends up doing and think about possible improvements.