Specify the minimum supported Rust version

Intentionally running CI with an older version because 1.81 fails on Windows due to windows-result requiring 1.82, and I want to see if that will also cause a failure on Ubuntu.

Author: Ortham

.github/workflows/ci.yml

@@ -56,6 +56,32 @@ jobs:
         cargo vet --version
         cargo vet --locked
 
+  msrv:
+    runs-on: ubuntu-24.04
+
+    env:
+      EXPECTED_MSRV: "1.81"
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/cache@v5
+        id: cache-cargo
+        with:
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+            target/
+          key: ${{ runner.os }}-msrv-cargo-${{ hashFiles('**/Cargo.lock') }}
+
+      - name: Install Rust v${{ env.EXPECTED_MSRV }}
+        run: rustup install ${EXPECTED_MSRV}
+
+      - name: Run cargo build using Rust v${{ env.EXPECTED_MSRV }}
+        run: cargo +${EXPECTED_MSRV} build --workspace --all-features
+
   build:
     strategy:
       matrix:

Cargo.toml

@@ -7,6 +7,7 @@ repository.workspace = true
 categories.workspace = true
 license.workspace = true
 edition.workspace = true
+rust-version.workspace = true
 
 [dependencies]
 dirs = ">= 1.0.0, < 7"
@@ -45,6 +46,7 @@ repository = "https://github.com/Ortham/libloadorder.git"
 categories = ["games"]
 license = "GPL-3.0"
 edition = "2021"
+rust-version = "1.82"
 
 # Deny some rustc lints that are allow-by-default.
 [workspace.lints.rust]

README.md

@@ -47,3 +47,7 @@ cmake -B ffi/build ffi
 cmake --build ffi/build
 ctest --test-dir ffi/build --output-on-failure
 ```
+
+## Minimum supported Rust version
+
+The minimum supported Rust version is `1.82`. This may change at any time, but there is a CI job to check that it does not change unexpectedly.

ffi/Cargo.toml

@@ -8,6 +8,7 @@ repository.workspace = true
 categories.workspace = true
 license.workspace = true
 edition.workspace = true
+rust-version.workspace = true
 
 [dependencies]
 libloadorder = { path = ".." }