Add a new "location" option

.github/workflows/Test.yml

@@ -374,3 +374,21 @@ jobs:
       uses: ./
       with:
         platform-check-severity: warn
+
+  location:
+    needs: [cache]
+    runs-on: windows-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/download-artifact@v2
+      with:
+        name: action
+    - name: run action
+      uses: ./
+      with:
+        location: 'D:\'
+        update: false
+    - shell: msys2 {0}
+      run: |
+        cygpath -m /
+

README.md

@@ -211,6 +211,7 @@ The package or list of packages are installed through `pacman --noconfirm -S --n
         git
         base-devel
 ```
+
 #### platform-check-severity
 
 By default (`fatal`), throw an error if the runner OS is not Windows.
@@ -221,3 +222,13 @@ If set to `warn`, simply log a message and skip the rest:
     with:
       platform-check-severity: warn
 ```
+
+#### location
+
+Specify the location where to install msys2:
+
+```yaml
+  - uses: msys2/setup-msys2@v2
+    with:
+      location: D:\
+```

action.yml

@@ -28,6 +28,10 @@ inputs:
     description: 'What to do when run on an incompatible runner: fatal, warn'
     required: false
     default: 'fatal'
+  location:
+    description: 'Where to install msys2'
+    required: false
+    default: 'RUNNER_TEMP'
 runs:
   using: 'node12'
   main: 'index.js'

main.js

@@ -28,6 +28,7 @@ function parseInput() {
   let p_msystem = core.getInput('msystem');
   let p_install = core.getInput('install');
   let p_platformcheckseverity = core.getInput('platform-check-severity');
+  let p_location = core.getInput('location');
 
   const msystem_allowed = ['MSYS', 'MINGW32', 'MINGW64', 'UCRT64', 'CLANG32', 'CLANG64'];
   if (!msystem_allowed.includes(p_msystem.toUpperCase())) {
@@ -42,13 +43,20 @@ function parseInput() {
     throw new Error(`'platform-check-severity' needs to be one of ${ platformcheckseverity_allowed.join(', ') }, got ${p_platformcheckseverity}`);
   }
 
+  if ( process.platform === 'win32' && (p_location === 'C:\\' || p_location === 'C:') ) {
+    throw new Error(`'location' cannot be 'C:' because that contains the built-in MSYS2 installation
+      in GitHub Actions environments. See option 'release', in order to use that installation:
+      https://github.com/msys2/setup-msys2#release`);
+  }
+
   return {
     release: p_release,
     update: p_update,
     pathtype: p_pathtype,
     msystem: p_msystem,
     install: p_install,
     platformcheckseverity: p_platformcheckseverity,
+    location: (p_location == "RUNNER_TEMP") ? process.env['RUNNER_TEMP'] : p_location,
   }
 }
 
@@ -220,7 +228,8 @@ async function run() {
     let msysRootDir = path.join('C:', 'msys64');
     if (input.release) {
       // Use upstream package instead of the default installation in the virtual environment.
-      msysRootDir = path.join(tmp_dir, 'msys64');
+      let dest = (input.location) ? input.location : tmp_dir;
+      msysRootDir = path.join(dest, 'msys64');
 
       if (INSTALL_CACHE_ENABLED) {
         instCache = new InstallCache(msysRootDir, input);
@@ -234,7 +243,7 @@ async function run() {
         let inst_dest = await downloadInstaller();
 
         changeGroup('Extracting MSYS2...');
-        await exec.exec(inst_dest, ['-y'], {cwd: tmp_dir});
+        await exec.exec(inst_dest, ['-y'], {cwd: dest});
 
         changeGroup('Disable Key Refresh...');
         await disableKeyRefresh(msysRootDir);