Tries to stabilize MSRV CI/CD. (#1485)

* Tries to stabilize MSRV CI/CD.

With the new MSRV-aware resolver available, I am trying to stabilize
our CI/CD, which frequently breaks due to dependency updates.
This takes three steps to do so:

1. Add Cargo.lock, so that builds on the CI/CD are deterministic
2. Add a regular (weekly) job that checks against the latest dependencies
across both stable and MSRV versions of rustc
3. Simplify the current CI/CD and revert to a single MSRV,
rather than using a BLAS-specific MSRV.

Author: akern40

.github/workflows/ci.yaml

@@ -16,6 +16,18 @@ env:
   BLAS_MSRV: 1.71.1
 
 jobs:
+  pass-msrv:
+    runs-on: ubuntu-latest
+    name: Pass MSRV values to other jobs
+    outputs:
+      MSRV: ${{ env.MSRV }}
+      BLAS_MSRV: ${{ env.BLAS_MSRV }}
+    steps:
+      - name: Pass MSRV
+        run: |
+          echo "MSRV=${{ env.MSRV }}" >> $GITHUB_OUTPUT
+          echo "BLAS_MSRV=${{ env.BLAS_MSRV }}" >> $GITHUB_OUTPUT
+
   clippy:
     runs-on: ubuntu-latest
     strategy:
@@ -70,13 +82,14 @@ jobs:
 
   tests:
     runs-on: ubuntu-latest
+    needs: pass-msrv
     strategy:
       matrix:
         rust:
           - stable
           - beta
           - nightly
-          - 1.64.0  # MSRV
+          - ${{ needs.pass-msrv.outputs.MSRV }}
 
     name: tests/${{ matrix.rust }}
     steps:
@@ -89,15 +102,16 @@ jobs:
       - name: Install openblas
         run: sudo apt-get install libopenblas-dev gfortran
       - run: ./scripts/all-tests.sh "$FEATURES" ${{ matrix.rust }}
-
+    
   blas-msrv:
     runs-on: ubuntu-latest
     name: blas-msrv
+    needs: pass-msrv
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: 1.71.1  # BLAS MSRV
+          toolchain: ${{ needs.pass-msrv.outputs.BLAS_MSRV }}
       - uses: rui314/setup-mold@v1
       - uses: Swatinem/rust-cache@v2
       - name: Install openblas

.github/workflows/latest-deps.yaml

@@ -0,0 +1,66 @@
+name: Check Latest Dependencies
+on:
+  schedule:
+    # Chosen so that it runs right before the international date line experiences the weekend.
+    # Since we're open source, that means globally we should be aware of it right when we have the most
+    # time to fix it.
+    #
+    # Sorry if this ruins your weekend, future maintainer...
+    - cron: '0 12 * * FRI'
+  workflow_dispatch: # For running manually
+
+env:
+  CARGO_TERM_COLOR: always
+  HOST: x86_64-unknown-linux-gnu
+  FEATURES: "approx,serde,rayon"
+  RUSTFLAGS: "-D warnings"
+  MSRV: 1.64.0
+  BLAS_MSRV: 1.71.0
+
+jobs:
+  latest_deps_stable:
+    runs-on: ubuntu-latest
+    name: Check Latest Dependencies on Stable
+    steps:
+      - name: Check Out Repo
+        uses: actions/checkout@v4
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: stable
+      - name: Setup Mold Linker
+        uses: rui314/setup-mold@v1
+      - name: Setup Rust Cache
+        uses: Swatinem/rust-cache@v2
+      - name: Install openblas
+        run: sudo apt-get install libopenblas-dev gfortran
+      - name: Ensure latest dependencies
+        run: cargo update
+      - name: Run Tests
+        run: ./scripts/all-tests.sh "$FEATURES" stable
+
+  latest_deps_msrv:
+    runs-on: ubuntu-latest
+    name: Check Latest Dependencies on MSRV (${{ env.MSRV }})
+    steps:
+      - name: Check Out Repo
+        uses: actions/checkout@v4
+      - name: Install Stable Rust for Update
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: stable
+      - name: Setup Mold Linker
+        uses: rui314/setup-mold@v1
+      - name: Setup Rust Cache
+        uses: Swatinem/rust-cache@v2
+      - name: Install openblas
+        run: sudo apt-get install libopenblas-dev gfortran
+      - name: Ensure latest dependencies
+        # The difference is here between this and `latest_deps_stable`
+        run: CARGO_RESOLVER_INCOMPATIBLE_RUST_VERSIONS="fallback" cargo update
+      - name: Install MSRV Rust for Test
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ env.MSRV }}
+      - name: Run Tests
+        run: ./scripts/all-tests.sh "$FEATURES" $MSRV

.gitignore

@@ -1,5 +1,4 @@
 # Rust items
-Cargo.lock
 target/
 
 # Editor settings