[GHA] Introduce reusable matrix workflow

# Motivation

We have a few checks that we want to run across all supported Swift versions e.g. unit tests and benchmarks. Right now we already added two matrix based jobs to the reusable workflow. This leads to a lot of duplication and harder maintenance.

# Modification

This PR splits off the current reusable workflow to only contain soundness related checks and introduces a new reusable matrix based workflow which can be customized to execute different commands.

# Result

It is now easy to setup multiple matrix based workflows.

.github/workflows/pull_request.yml

@@ -5,10 +5,17 @@ on:
     types: [opened, reopened, synchronize, ready_for_review]
 
 jobs:
-  call-reusable-pull-request-workflow:
+  call-pull-request-soundness-workflow:
     name: Checks
-    uses: ./.github/workflows/reusable_pull_request.yml
+    uses: ./.github/workflows/pull_request_soundness.yml
     with:
       benchmarks_linux_package_path: "Benchmarks"
       license_header_check_project_name: "SwiftNIO"
       format_check_enabled: false
+
+    call-pull-request-unit-tests-workflow:
+      name: Checks
+      uses: ./.github/workflows/pull_request_swift_matrix.yml
+      with:
+        matrix_linux_name: "Unit tests"
+        matrix_linux_command: "swift test"

.github/workflows/reusable_pull_request.yml → .github/workflows/pull_request_soundness.yml

@@ -3,18 +3,6 @@ name: Pull Request
 on:
   workflow_call:
     inputs:
-      unit_tests_linux_enabled:
-        type: boolean
-        description: "Boolean to enable the unit tests linux job. Defaults to true."
-        default: true
-      benchmarks_linux_enabled:
-        type: boolean
-        description: "Boolean to enable the benchmarks linux job. Defaults to true."
-        default: true
-      benchmarks_linux_package_path:
-        type: string
-        description: "Path to the package containing the benchmarks. Defaults to the repository root."
-        default: "."
       api_breakage_check_enabled:
         type: boolean
         description: "Boolean to enable the API breakage check job. Defaults to true."
@@ -54,60 +42,6 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  unit-tests-linux:
-    name: Unit tests
-    if: ${{ inputs.unit_tests_linux_enabled }}
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        swift:
-        - image: swift:5.8-jammy
-        - image: swift:5.9-jammy
-        - image: swift:5.10-jammy
-        - image: swiftlang/swift:nightly-6.0-jammy
-        - image: swiftlang/swift:nightly-main-jammy
-    container:
-      image: ${{ matrix.swift.image }}
-    timeout-minutes: 20
-    steps:
-    - name: Checkout repository
-      uses: actions/checkout@v4
-    - name: Run tests
-      run: swift test
-
-  benchmarks-linux:
-    name: Benchmarks
-    if: ${{ inputs.benchmarks_linux_enabled }}
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        swift:
-        - image: swift:5.8-jammy
-          swift_version: "5.8"
-        - image: swift:5.9-jammy
-          swift_version: "5.9"
-        - image: swift:5.10-jammy
-          swift_version: "5.10"
-        - image: swiftlang/swift:nightly-6.0-jammy
-          swift_version: "nightly-next"
-        - image: swiftlang/swift:nightly-main-jammy
-          swift_version: "nightly-main"
-    container:
-      image: ${{ matrix.swift.image }}
-    timeout-minutes: 20
-    steps:
-    - name: Checkout repository
-      uses: actions/checkout@v4
-    - name: Run tests
-      env:
-        PACKAGE_PATH: ${{ inputs.benchmarks_linux_package_path }}
-        SWIFT_VERSION: ${{ matrix.swift.swift_version }}
-      run: |
-        apt-get update -y -q && apt-get install -y -q libjemalloc-dev
-        swift package --package-path ${PACKAGE_PATH} --disable-sandbox benchmark baseline check --check-absolute-path ${PACKAGE_PATH}/Thresholds/${SWIFT_VERSION}/
-
   api-breakage-check:
     name: API breakage check
     if: ${{ inputs.api_breakage_check_enabled }}

.github/workflows/pull_request_swift_matrix.yml

@@ -0,0 +1,81 @@
+name: Pull Request
+
+on:
+  workflow_call:
+    inputs:
+      matrix_linux_name:
+        type: string
+        description: "The name of the linux matrix job."
+        required: true
+      matrix_linux_command:
+        type: string
+        description: "The command of the current Swift version linux matrix job to execute."
+        required: true
+      matrix_linux_5_8_enabled:
+        type: string
+        description: "The command of the 5.8 Swift version linux matrix job to execute."
+      matrix_linux_5_8_command_override:
+        type: string
+        description: "The command of the 5.8 Swift version linux matrix job to execute."
+      matrix_linux_5_9_enabled:
+        type: string
+        description: "The command of the 5.9 Swift version linux matrix job to execute."
+      matrix_linux_5_9_command_override:
+        type: string
+        description: "The command of the 5.9 Swift version linux matrix job to execute."
+      matrix_linux_5_10_enabled:
+        type: string
+        description: "The command of the 5.10 Swift version linux matrix job to execute."
+      matrix_linux_5_10_command_override:
+        type: string
+        description: "The command of the 5.10 Swift version linux matrix job to execute."
+      matrix_linux_nightly_next_enabled:
+        type: string
+        description: "The command of the nightly next Swift version linux matrix job to execute."
+      matrix_linux_nightly_next_command_override:
+        type: string
+        description: "The command of the nightly next Swift version linux matrix job to execute."
+      matrix_linux_nightly_main_enabled:
+        type: string
+        description: "The command of the nightly main Swift version linux matrix job to execute."
+      matrix_linux_nightly_main_command_override:
+        type: string
+        description: "The command of the nightly main Swift version linux matrix job to execute."
+
+## We are cancelling previously triggered workflow runs
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  matrix-linux:
+    name: ${{ inputs.matrix_linux_name }} (${{ matrix.swift_version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        swift:
+        - image: swift:5.8-jammy
+          swift_version: "5.8"
+        - image: swift:5.9-jammy
+          swift_version: "5.9"
+        - image: swift:5.10-jammy
+          swift_version: "5.10"
+        - image: swiftlang/swift:nightly-6.0-jammy
+          swift_version: "nightly-next"
+        - image: swiftlang/swift:nightly-main-jammy
+          swift_version: "nightly-main"
+    container:
+      image: ${{ matrix.swift.image }}
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+    - name: Run matrix job
+      env:
+        SWIFT_VERSION: ${{ matrix.swift.swift_version }}
+        5_8_OVERRIDE: "${{ github.event.inputs.matrix_linux_5_8_command_override != '' }}"
+        5_9_OVERRIDE: "${{ github.event.inputs.matrix_linux_5_9_command_override != '' }}"
+        5_10_OVERRIDE: "${{ github.event.inputs.matrix_linux_5_10_command_override != '' }}"
+        5_9_OVERRIDE: "${{ github.event.inputs.matrix_linux_5_8_command_override != '' }}"
+        5_9_OVERRIDE: "${{ github.event.inputs.matrix_linux_5_8_command_override != '' }}"
+      run: ${{ inputs.matrix_linux_command }}