Add option to use mysys2 instead of cygwin

Github runners come with mysys2 installed (This is what is used when you
call `shell: bash` on a windows runner.) Using mysys2 means we can avoid
the rather costly cygwin install costs during builds.

.github/workflows/test.yaml

@@ -11,6 +11,10 @@ jobs:
     strategy:
       matrix:
         os: [windows-2022, macos-latest, ubuntu-latest]
+        cygwin: [false]
+        include:
+          - os: windows-2022
+            cygwin: true
     runs-on: ${{ matrix.os }}
     env:
       AUTOBUILD_CONFIGURATION: default
@@ -30,6 +34,7 @@ jobs:
       - uses: ./
         with:
           artifact-name: autobuild-${{ matrix.os }}
+          cygwin: ${{ matrix.cygwin }}
           checkout: false
 
       - shell: bash
@@ -38,20 +43,23 @@ jobs:
       - uses: ./
         with:
           artifact-name: autobuild-scm-${{ matrix.os }}
+          cygwin: ${{ matrix.cygwin }}
           checkout: false
           file: autobuild-scm.xml
 
       # Test git-based autobuild install
       - uses: ./
         with:
           artifact-name: autobuild-git-${{ matrix.os }}
+          cygwin: ${{ matrix.cygwin }}
           autobuild-version: main
           checkout: false
-      
+
       # Test alternative compression-format
       - uses: ./
         with:
           artifact-name: autobuild-tbz2-${{ matrix.os }}
+          cygwin: ${{ matrix.cygwin }}
           archive-format: tbz2
           checkout: false
       - name: Check bz2 package
@@ -66,9 +74,10 @@ jobs:
       - uses: ./
         with:
           artifact-name: autobuild-py310-${{ matrix.os }}
+          cygwin: ${{ matrix.cygwin }}
           setup-python: false
       - name: Check python version
         shell: bash
         run: |
           ver="$(python --version)"
-          [[ "$ver" == "Python 3.10."* ]] || exit "Expected python 3.10, got $ver" 
+          [[ "$ver" == "Python 3.10."* ]] || exit "Expected python 3.10, got $ver"

action.yaml

@@ -51,6 +51,13 @@ inputs:
     type: string
     description: Version of autobuild to install
     default: 3.*
+  cygwin:
+    type: boolean
+    description: Install and use cygwin
+    default: "false"
+  mysys2-packages:
+    type: string
+    description: Additional mysys2 packages to install
   cygwin-packages:
     type: string
     description: Additional cygwin packages to install
@@ -137,22 +144,28 @@ runs:
         if [[ $VERSION =~ ^[0-9] ]]; then
           pip install "autobuild==$VERSION"
         else
-          pip install "autobuild @ git+https://github.com/secondlife/autobuild@$VERSION" 
+          pip install "autobuild @ git+https://github.com/secondlife/autobuild@$VERSION"
         fi
 
     - name: Setup cygwin
-      if: ${{ runner.os == 'Windows' }}
+      if: ${{ runner.os == 'Windows' && inputs.cygwin != 'false' }}
       uses: secondlife/setup-cygwin@v3
       with:
         packages: ${{ inputs.cygwin-packages }}
 
+    - name: Setup mysys2
+      if: ${{ runner.os == 'Windows' && fromJSON(inputs.mysys2-packages) }}
+      shell: bash
+      run: pacman -Sy --noconfirm ${{ inputs.mysys2-packages }}
+
     - name: Determine shell
       id: shell
       shell: bash
       env:
         WINDOWS: ${{ runner.os == 'Windows' }}
+        CYGWIN: ${{ inputs.cygwin != 'false' }}
       run: |
-        if [[ $WINDOWS == 'true' ]]; then
+        if [[ $WINDOWS == 'true' && $CYGWIN == 'true' ]]; then
           echo "shell=C:\cygwin64\bin\bash.exe --login --norc -eo pipefail -o igncr '{0}'" >> $GITHUB_OUTPUT
         else
           echo "shell=bash" >> $GITHUB_OUTPUT
@@ -187,6 +200,7 @@ runs:
         AUTOBUILD_VCS_URL: ${{ github.repositoryUrl }}
         BUILD_ID: ${{ inputs.build-id }}
         CONFIGURATION: ${{ inputs.configuration }}
+        MSYS2_ARG_CONV_EXCL: "*" # Disable MSYS2 path conversion
         PLATFORM: ${{ inputs.platform }}
         SHORT_SHA: ${{ steps.sha.outputs.short }}
         WINDOWS: ${{ runner.os == 'Windows' }}