Use ImageOS for the cache key, so it also includes the OS version

Author: eregon

common.js

@@ -59,6 +59,14 @@ function findUbuntuVersion() {
   }
 }
 
+export function getImageOS() {
+  const imageOS = process.env['ImageOS']
+  if (!imageOS) {
+    throw new Error('The environment variable ImageOS must be set')
+  }
+  return imageOS
+}
+
 export function shouldExtractInToolCache(engine, version) {
   return engine === 'ruby' && !isHeadVersion(version)
 }

dist/index.js

@@ -293,7 +293,7 @@ async function bundleInstall(gemfile, lockFile, platform, engine, version) {
 }
 
 async function computeBaseKey(platform, engine, version, lockFile) {
-  let key = `setup-ruby-bundler-cache-v2-${platform}-${engine}-${version}`
+  let key = `setup-ruby-bundler-cache-v2-${common.getImageOS()}-${engine}-${version}`
 
   if (engine !== 'jruby' && common.isHeadVersion(version)) {
     let revision = '';