Default to the latest GitHub release

README.md

@@ -9,7 +9,7 @@ This action provides the following functionality for GitHub Actions users:
 
 See [action.yml](action.yml)
 
-**Basic:**
+**Basic** (automatically uses the latest GitHub release):
 
 ```yaml
 steps:

action.yml

@@ -4,9 +4,8 @@ author: 'amyu'
 
 inputs:
   version:
-    description: 'Bundletool version'
+    description: 'Bundletool version. If not specified, downloads the latest GitHub release.'
     required: false
-    default: '1.18.3'
 
 runs:
   using: 'node24'

src/main.ts

@@ -4,9 +4,43 @@ import fs from 'fs/promises'
 import path from 'path'
 import os from 'os'
 
+// Fetch the latest release metadata from GitHub
+async function getLatestVersion(): Promise<string> {
+  const response = await fetch(
+    'https://github.com/google/bundletool/releases/latest',
+    {redirect: 'manual'}
+  )
+
+  const location = response.headers.get('location')
+
+  if (!location) {
+    throw new Error(
+      'Unable to determine latest release location from GitHub response'
+    )
+  }
+
+  const tag = location.split('/').pop()
+
+  if (!tag) {
+    throw new Error(
+      'Unable to extract version tag from GitHub redirect location'
+    )
+  }
+
+  return tag
+}
+
+// Main action entry point
 async function run(): Promise<void> {
   try {
-    const version = core.getInput('version')
+    let version = core.getInput('version')
+
+    if (!version) {
+      core.info('Fetching latest bundletool release from GitHub…')
+      version = await getLatestVersion()
+      core.info(`Using latest version: ${version}`)
+    }
+
     const downloadVersion = `${version}/bundletool-all-${version}.jar`
 
     const downloadDir = path.join(os.homedir(), '.bundletool')