chore: refactor CI msrv & minver checks (#2238)

## Motivation

Test msrv and minimal-versions compliance in the currently best-known
fashion.

## Solution

- Use cargo-hack and cargo-minimal-versions
- Also I replaced uses of actions-rs (abandoned) while I was passing by

Author: CAD97

.github/workflows/CI.yml

@@ -26,9 +26,6 @@ env:
   RUSTUP_MAX_RETRIES: 10
   # Don't emit giant backtraces in the CI logs.
   RUST_BACKTRACE: short
-  MSRV: 1.49.0
-  # TODO: remove this once tracing's MSRV is bumped.
-  APPENDER_MSRV: 1.53.0
 
 jobs:
   ### check jobs ###
@@ -39,16 +36,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
-      with:
-        toolchain: stable
-        profile: minimal
-        override: true
+    - uses: dtolnay/rust-toolchain@stable
     - name: Check
-      uses: actions-rs/cargo@v1
-      with:
-        command: check
-        args: --all --tests --benches
+      run: cargo check --all --tests --benches
 
   style:
     # Check style.
@@ -57,64 +47,27 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
+    - uses: dtolnay/rust-toolchain@stable
       with:
-        toolchain: stable
         components: rustfmt
-        profile: minimal
-        override: true
     - name: rustfmt
-      uses: actions-rs/cargo@v1
-      with:
-        command: fmt
-        args: --all -- --check
+      run: cargo fmt --all -- --check
 
   warnings:
     # Check for any warnings. This is informational and thus is allowed to fail.
     runs-on: ubuntu-latest
     needs: check
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
+    - uses: dtolnay/rust-toolchain@stable
       with:
-        toolchain: stable
         components: clippy
-        profile: minimal
     - name: Clippy
       uses: actions-rs/clippy-check@v1
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
         args: --all --examples --tests --benches -- -D warnings
 
-  minimal-versions:
-    # Check for minimal-versions errors where a dependency is too
-    # underconstrained to build on the minimal supported version of all
-    # dependencies in the dependency graph.
-    name: cargo check (-Zminimal-versions)
-    needs: check
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          profile: minimal
-          override: true
-      - name: install cargo-hack
-        uses: taiki-e/install-action@cargo-hack
-      - name: "check --all-features -Z minimal-versions"
-        run: |
-          # Remove dev-dependencies from Cargo.toml to prevent the next `cargo update`
-          # from determining minimal versions based on dev-dependencies.
-          cargo hack --remove-dev-deps --workspace
-          # Update Cargo.lock to minimal version dependencies.
-          cargo update -Z minimal-versions
-          cargo hack check \
-            --package tracing \
-            --package tracing-core \
-            --package tracing-subscriber \
-            --all-features --ignore-private
-
   cargo-hack:
     needs: check
     name: cargo check (feature combinations)
@@ -137,11 +90,7 @@ jobs:
         - tracing-subscriber
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
-      with:
-        toolchain: stable
-        profile: minimal
-        override: true
+    - uses: dtolnay/rust-toolchain@stable
 
     - name: install cargo-hack
       uses: taiki-e/install-action@cargo-hack
@@ -174,77 +123,80 @@ jobs:
       shell: bash
 
   check-msrv:
-    # Run `cargo check` on our minimum supported Rust version (1.49.0).
-    name: "cargo check (MSRV on ubuntu-latest)"
-    needs: check
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v3
-    - name: "install Rust ${{ env.MSRV }}"
-      uses: actions-rs/toolchain@v1
-      with:
-        toolchain: ${{ env.MSRV }}
-        profile: minimal
-    - name: "install Rust nightly"
-      uses: actions-rs/toolchain@v1
-      with:
-        toolchain: nightly
-        profile: minimal
-    - name: Select minimal versions
-      uses: actions-rs/cargo@v1
-      with:
-        command: update
-        args: -Z minimal-versions
-        toolchain: nightly
-    - name: Check
-      uses: actions-rs/cargo@v1
-      with:
-        command: check
-        # skip the following crates:
-        # - tracing-appender, as it has its own MSRV.
-        #   TODO(eliza): remove this when appender is on the same MSRV as
-        #   everything else
-        # - the examples, as they are not published & we don't care about
-        #   MSRV support for them.
-        # - tracing-futures, as it depends on ancient tokio versions.
-        #   TODO(eliza): remove this when the ancient tokio deps are dropped
-        args: >-
-          --workspace --all-features --locked
-          --exclude=tracing-appender
-          --exclude=tracing-examples
-          --exclude=tracing-futures
-        toolchain: ${{ env.MSRV }}
-
-  # TODO: remove this once tracing's MSRV is bumped.
-  check-msrv-appender:
-    # Run `cargo check` on our minimum supported Rust version (1.53.0).
-    name: "cargo check (tracing-appender MSRV)"
+    # Run `cargo check` on our minimum supported Rust version (1.49.0). This
+    # checks with minimal versions; maximal versions are checked above.
+    name: "cargo check (+MSRV -Zminimal-versions)"
     needs: check
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # cargo hack --feature-powerset will have a significant permutation
+        # number, we can't just use --all as it increases the runtime
+        # further than what we would like to
+        subcrate:
+        - tracing-attributes
+        - tracing-core
+        - tracing-futures
+        - tracing-log
+        - tracing-macros
+        - tracing-serde
+        - tracing-tower
+        - tracing-opentelemetry
+        - tracing
+        - tracing-subscriber
+        toolchain:
+        - 1.49.0
+        - stable
+        # TODO(eliza): remove this when appender is on the same MSRV.
+        exclude:
+        - subcrate: tracing-appender
+          toolchain: 1.49.0
+        include:
+        - subcrate: tracing-appender
+          toolchain: 1.53.0
     steps:
     - uses: actions/checkout@v3
-    - name: "install Rust ${{ env.APPENDER_MSRV }}"
-      uses: actions-rs/toolchain@v1
-      with:
-        toolchain: ${{ env.APPENDER_MSRV }}
-        profile: minimal
-    - name: "install Rust nightly"
-      uses: actions-rs/toolchain@v1
+    - name: install Rust nightly
+      uses: dtolnay/rust-toolchain@nightly
+    - name: "install Rust ${{ matrix.toolchain }}"
+      uses: dtolnay/rust-toolchain@master
       with:
-        toolchain: nightly
-        profile: minimal
-    - name: Select minimal versions
-      uses: actions-rs/cargo@v1
-      with:
-        command: update
-        args: -Z minimal-versions
-        toolchain: nightly
-    - name: Check
-      uses: actions-rs/cargo@v1
-      with:
-        command: check
-        args: --all-features --locked -p tracing-appender
-        toolchain: ${{ env.APPENDER_MSRV }}
+        toolchain: ${{ matrix.toolchain }}
+    - name: install cargo-hack
+      uses: taiki-e/install-action@cargo-hack
+    - name: install cargo-minimal-versions
+      uses: taiki-e/install-action@cargo-minimal-versions
+    - name: cargo minimal-versions check
+      working-directory: ${{ matrix.subcrate }}
+      # tracing and tracing-subscriber have too many features to be checked by
+      # cargo-hack --feature-powerset with all features in the powerset, so
+      # exclude some
+      run: |
+        CARGO_MINVER=(cargo minimal-versions check --feature-powerset --no-dev-deps)
+        case "${{ matrix.subcrate }}" in
+          tracing)
+            EXCLUDE_FEATURES=(
+              max_level_off max_level_error max_level_warn max_level_info
+              max_level_debug max_level_trace release_max_level_off
+              release_max_level_error release_max_level_warn
+              release_max_level_info release_max_level_debug
+              release_max_level_trace
+            )
+            ${CARGO_MINVER[@]} --exclude-features "${EXCLUDE_FEATURES[*]}"
+            ;;
+          tracing-subscriber)
+            INCLUDE_FEATURES=(fmt ansi json registry env-filter)
+            ${CARGO_MINVER[@]} --include-features "${INCLUDE_FEATURES[*]}"
+            ;;
+          tracing-futures)
+            EXCLUDE_FEATURES=(futures-01 futures_01 tokio tokio_01)
+            ${CARGO_MINVER[@]} --exclude-features "${EXCLUDE_FEATURES[*]}"
+            ;;
+          *)
+            ${CARGO_MINVER[@]}
+            ;;
+        esac
+      shell: bash
 
   ### test jobs #############################################################
 
@@ -268,11 +220,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
+    - name: "install Rust ${{ matrix.rust }}"
+      uses: dtolnay/rust-toolchain@master
       with:
         toolchain: ${{ matrix.rust }}
-        profile: minimal
-        override: true
     - name: install cargo-nextest
       uses: taiki-e/install-action@nextest
     - name: Run tests
@@ -312,16 +263,11 @@ jobs:
       fail-fast: false
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
+    - uses: dtolnay/rust-toolchain@stable
       with:
         target: wasm32-unknown-unknown
-        toolchain: stable
-        override: true
     - name: build all tests
-      uses: actions-rs/cargo@v1
-      with:
-        command: test
-        args: --no-run -p ${{ matrix.subcrate }}
+      run: cargo test --no-run -p ${{ matrix.subcrate }}
 
   test-wasm:
     name: cargo test (wasm)
@@ -333,11 +279,9 @@ jobs:
         - tracing
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
+    - uses: dtolnay/rust-toolchain@stable
       with:
         target: wasm32-unknown-unknown
-        toolchain: stable
-        override: true
     - name: install test runner for wasm
       uses: taiki-e/install-action@wasm-pack
     - name: run wasm tests
@@ -353,11 +297,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
-      with:
-        toolchain: stable
-        profile: minimal
-        override: true
+    - uses: dtolnay/rust-toolchain@stable
     - name: "Test log support"
       run: cargo test
       working-directory: "tracing/test-log-support"
@@ -386,10 +326,8 @@ jobs:
     runs-on: ubuntu-latest
     needs:
       - style
-      - minimal-versions
       - cargo-hack
       - check-msrv
-      - check-msrv-appender
       - test-build-wasm
       - test-wasm
       - test-features-stable