Add support for running Linux-based actions workflows locally using nektos/act

.actrc

@@ -0,0 +1,3 @@
+--env=PIP_BREAK_SYSTEM_PACKAGES=1
+--env=PIP_ROOT_USER_ACTION=ignore
+--eventpath=.github/act/push-and-merge-group-events.json

.github/act/push-and-merge-group-events.json

@@ -0,0 +1,9 @@
+{
+  "ref": "",
+  "repository": {
+    "default_branch": "develop"
+  },
+  "merge_group": {
+    "base_ref": "develop"
+  }
+}

.github/workflows/audit.yaml

@@ -19,10 +19,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        system:
-        - { os: windows-latest, shell: powershell }
-        - { os: ubuntu-latest, shell: bash }
-        - { os: macos-latest, shell: bash }
+        # In a local docker-based workflow run using act, only Linux-based systems are available
+        system: >-
+          ${{ github.actor == 'nektos/act'
+              && fromJSON('[{"os":"ubuntu-latest","shell":"bash"}]')
+              || fromJSON('[{"os":"ubuntu-latest","shell":"bash"},
+                           {"os":"windows-latest","shell":"powershell"},
+                           {"os":"macos-latest","shell":"bash"}]') }}
         # An empty ref means the commit pinned in .ci/env, the others are the
         # released versions we keep the packages repository compatible with
         spack_ref: ['', 'v1.2.2', 'v1.1.1']

.github/workflows/bootstrap.yml

@@ -69,6 +69,11 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
         with:
           fetch-depth: 0
+      - name: Install Node.js for local workflow runs using act
+        if: ${{ github.actor == 'nektos/act' }}
+        run: |
+          yum update -y
+          yum install -y nodejs
       - uses: ./.github/actions/checkout-spack
       - name: Bootstrap clingo
         run: |
@@ -176,6 +181,7 @@ jobs:
 
   bootstrap-dev-rhel8:
     runs-on: ubuntu-latest
+    if: ${{ github.actor != 'nektos/act' }}
     container: registry.access.redhat.com/ubi8/ubi
     steps:
       - name: Install dependencies
@@ -187,6 +193,11 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
         with:
           fetch-depth: 0
+      - name: Install Node.js for local workflow runs using act
+        if: ${{ github.actor == 'nektos/act' }}
+        run: |
+          yum update -y
+          yum install -y nodejs
       - uses: ./.github/actions/checkout-spack
         with:
           fetch-depth: 0

.github/workflows/prechecks.yml

@@ -80,6 +80,11 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
         with:
           fetch-depth: 0
+      - name: Install Node.js for local workflow runs using act
+        if: ${{ github.actor == 'nektos/act' }}
+        run: |
+          apt-get update
+          apt-get install -y nodejs
       - uses: ./.github/actions/checkout-spack
 
       - name: Test package.py canonicalization

.github/workflows/triage.yml

@@ -14,6 +14,7 @@ on:
 jobs:
   pr:
     runs-on: ubuntu-latest
+    if: ${{ github.actor != 'nektos/act' }}
     permissions:
       contents: read
       pull-requests: write

.github/workflows/unit_tests.yaml

@@ -1,6 +1,9 @@
 name: unit tests
 
 on:
+  # Allows act's default push event to select this workflow locally. The job
+  # guards below prevent this local-only trigger from running tests on GitHub.
+  push:
   workflow_dispatch:
   workflow_call:
 
@@ -11,6 +14,9 @@ concurrency:
 jobs:
   # Run unit tests with different configurations on linux
   ubuntu:
+    # Run act's synthetic push, or GitHub's workflow_call/dispatch events, but
+    # skip ordinary GitHub push events introduced only for act compatibility.
+    if: ${{ github.actor == 'nektos/act' || github.event_name != 'push' }}
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
@@ -39,6 +45,8 @@ jobs:
     steps:
     - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
     - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97  # v7.0.0
+      # In local workflow runs using act, setup-python is not supported and not needed
+      if: ${{ github.actor != 'nektos/act' }}
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install System packages
@@ -56,6 +64,8 @@ jobs:
 
   # Run unit tests on MacOS
   macos:
+    # Keep the same event guard as the Linux matrix; act skips this platform.
+    if: ${{ github.actor == 'nektos/act' || github.event_name != 'push' }}
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
@@ -76,6 +86,8 @@ jobs:
 
   # Run unit tests on Windows
   windows:
+    # Keep the same event guard as the Linux matrix; act skips this platform.
+    if: ${{ github.actor == 'nektos/act' || github.event_name != 'push' }}
     defaults:
       run:
         shell: