Better error for 404

index.js

@@ -164,8 +164,8 @@ function validateRubyEngineAndVersion(platform, engineVersions, engine, parsedVe
     if (found) {
       version = found
     } else {
-      throw new Error(`Unknown version ${parsedVersion} for ${engine} on ${platform}
-        available versions for ${engine} on ${platform}: ${engineVersions.join(', ')}
+      throw new Error(`Unknown version ${parsedVersion} for ${engine} on ${platform}.
+        Available versions for ${engine} on ${platform}: ${engineVersions.join(', ')}.
         Make sure you use the latest version of the action with - uses: ruby/setup-ruby@v1`)
     }
   }

ruby-builder.js

@@ -69,7 +69,17 @@ async function downloadAndExtract(platform, engine, version, rubyPrefix) {
   const downloadPath = await common.measure('Downloading Ruby', async () => {
     const url = getDownloadURL(platform, engine, version)
     console.log(url)
-    return await tc.downloadTool(url)
+    try {
+      return await tc.downloadTool(url)
+    } catch (error) {
+      if (error.message.endsWith('404')) {
+        throw new Error(`Unavailable version ${version} for ${engine} on ${platform}.
+          You can request it at https://github.com/ruby/setup-ruby/issues.
+          Original Error: (${error.message})`)
+      } else {
+        throw error
+      }
+    }
   })
 
   await common.measure('Extracting  Ruby', async () => {