Switch to composite action

action.yml

@@ -11,6 +11,14 @@ inputs:
     required: false
     default: 'true'
 
+# Note:
+# - inputs.* should be manually mapped to INPUT_* due to https://github.com/actions/runner/issues/665
+# - Use GITHUB_*/RUNNER_* instead of github.*/runner.* due to https://github.com/actions/runner/issues/2185
 runs:
-  using: node16
-  main: main.js
+  using: composite
+  steps:
+    - run: bash --noprofile --norc "${GITHUB_ACTION_PATH:?}/main.sh"
+      shell: bash
+      env:
+        INPUT_TOOL: ${{ inputs.tool }}
+        INPUT_CHECKSUM: ${{ inputs.checksum }}

main.js

@@ -1,28 +0,0 @@
-// This is a script that just calls the bash script that does the main
-// processing of the action. It works like a composite action that calls
-// a single bash script.
-//
-// This was originally a trick adopted to make bash script-based actions work
-// without docker before composite actions were supported. However, due to
-// various problems with composite actions, this trick is still needed:
-// - https://github.com/actions/runner/issues/665
-// - https://github.com/actions/runner/issues/2185
-// Although there are ways to work around these like cache-cargo-install-action does:
-// https://github.com/taiki-e/cache-cargo-install-action/blob/v1.0.1/action.yml#L9-L11
-
-const { execFileSync } = require('child_process');
-
-function main() {
-    try {
-        execFileSync(
-            'bash',
-            ['--noprofile', '--norc', `${__dirname}/main.sh`],
-            { stdio: 'inherit' }
-        );
-    } catch (e) {
-        console.log(`::error::${e.message}`);
-        process.exit(1);
-    }
-}
-
-main();