Use an explicit list of supported platforms for nicer error messages

Author: eregon

common.js

@@ -98,6 +98,15 @@ function getImageOS() {
   return imageOS
 }
 
+export const supportedPlatforms = [
+  'ubuntu-18.04',
+  'ubuntu-20.04',
+  'macos-10.15',
+  'macos-11.0',
+  'windows-2019',
+  'windows-2022',
+]
+
 export function getVirtualEnvironmentName() {
   const imageOS = getImageOS()
 

dist/index.js

@@ -42,7 +42,7 @@ export async function setupRuby(options = {}) {
   const [engine, parsedVersion] = parseRubyEngineAndVersion(inputs['ruby-version'])
 
   let installer
-  if (platform.startsWith('windows-') && engine !== 'jruby') {
+  if (platform.startsWith('windows-') && engine === 'ruby') {
     installer = require('./windows')
   } else {
     installer = require('./ruby-builder')

index.js

@@ -13,6 +13,10 @@ const releasesURL = 'https://github.com/ruby/ruby-builder/releases'
 const windows = common.windows
 
 export function getAvailableVersions(platform, engine) {
+  if (!common.supportedPlatforms.includes(platform)) {
+    throw new Error(`Unsupported platform ${platform}`)
+  }
+
   return rubyBuilderVersions[engine]
 }
 

ruby-builder.js

@@ -25,6 +25,10 @@ const msysPathEntries = [`${msys1}\\mingw\\x86_64-w64-mingw32\\bin`, `${msys1}\\
 const virtualEnv = common.getVirtualEnvironmentName()
 
 export function getAvailableVersions(platform, engine) {
+  if (!common.supportedPlatforms.includes(platform)) {
+    throw new Error(`Unsupported platform ${platform}`)
+  }
+
   if (engine === 'ruby') {
     return Object.keys(rubyInstallerVersions)
   } else {