Use a hardcoded toolcache path since we need to extract there to let Ruby work

https://www.ruby-lang.org/en/news/2020/04/05/support-of-ruby-2-4-has-ended/

README.md

@@ -29,9 +29,8 @@ Only versions published by [RubyInstaller](https://rubyinstaller.org/downloads/a
 Due to that, Ruby 2.2 resolves to 2.2.6 on Windows and 2.2.10 on other platforms.
 And Ruby 2.3 on Windows only has builds for 2.3.0, 2.3.1 and 2.3.3.
 
-Note that Ruby ≤ 2.3 and the OpenSSL version it needs (1.0.2) are both end-of-life,
-which means Ruby ≤ 2.3 is unmaintained and considered insecure.
-On Windows, Ruby 2.4 uses OpenSSL 1.0.2, which is no longer maintained.
+Note that Ruby ≤ 2.4 and the OpenSSL version it needs (1.0.2) are both end-of-life,
+which means Ruby ≤ 2.4 is unmaintained and considered insecure.
 
 ### Supported Platforms
 
@@ -204,7 +203,10 @@ if the [virtual environment](https://github.com/actions/virtual-environments) is
 * Make sure to use the same operating system and version.
 * Make sure to use the same version of libssl.
 * Make sure that the operating system has `libyaml-0` installed
-* The runner software is running as user `runner` with a home directory of `/home/runner`, or you have created a symlink for the home directory of whatever user that the runner is running as to `/home/runner`.
+* The default tool cache directory (`/opt/hostedtoolcache` on Linux, `/Users/runner/hostedtoolcache` on macOS,
+  `C:/hostedtoolcache/windows` on Windows) must be writable by the `runner` user.
+  This is necessary since the Ruby builds embed the install path when built and cannot be moved around.
+* `/home/runner` must be writable by the `runner` user.
 
 In other cases, please use a system Ruby or [install Ruby manually](https://github.com/postmodern/chruby/wiki#installing-rubies) instead.
 

common.js

@@ -63,11 +63,21 @@ export function shouldExtractInToolCache(engine, version) {
   return engine === 'ruby' && !isHeadVersion(version)
 }
 
-export function getToolCacheRubyPrefix(version) {
-  const toolCache = process.env['RUNNER_TOOL_CACHE']
-  if (!toolCache) {
-    throw new Error('$RUNNER_TOOL_CACHE must be set')
+function getPlatformToolCache(platform) {
+  // Hardcode paths rather than using $RUNNER_TOOL_CACHE because the prebuilt Rubies cannot be moved anyway
+  if (platform.startsWith('ubuntu-')) {
+    return '/opt/hostedtoolcache'
+  } else if (platform.startsWith('macos-')) {
+    return '/Users/runner/hostedtoolcache'
+  } else if (platform.startsWith('windows-')) {
+    return 'C:/hostedtoolcache/windows'
+  } else {
+    throw new Error('Unknown platform')
   }
+}
+
+export function getToolCacheRubyPrefix(platform, version) {
+  const toolCache = getPlatformToolCache(platform)
   return path.join(toolCache, 'Ruby', version, 'x64')
 }
 

dist/index.js

@@ -27714,7 +27714,7 @@ async function install(platform, engine, version) {
 
   let rubyPrefix
   if (common.shouldExtractInToolCache(engine, version)) {
-    rubyPrefix = common.getToolCacheRubyPrefix(version)
+    rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
   } else {
     rubyPrefix = `${drive}:\\${base}`
   }
@@ -32167,11 +32167,21 @@ function shouldExtractInToolCache(engine, version) {
   return engine === 'ruby' && !isHeadVersion(version)
 }
 
-function getToolCacheRubyPrefix(version) {
-  const toolCache = process.env['RUNNER_TOOL_CACHE']
-  if (!toolCache) {
-    throw new Error('$RUNNER_TOOL_CACHE must be set')
+function getPlatformToolCache(platform) {
+  // Hardcode paths rather than using $RUNNER_TOOL_CACHE because the prebuilt Rubies cannot be moved anyway
+  if (platform.startsWith('ubuntu-')) {
+    return '/opt/hostedtoolcache'
+  } else if (platform.startsWith('macos-')) {
+    return '/Users/runner/hostedtoolcache'
+  } else if (platform.startsWith('windows-')) {
+    return 'C:/hostedtoolcache/windows'
+  } else {
+    throw new Error('Unknown platform')
   }
+}
+
+function getToolCacheRubyPrefix(platform, version) {
+  const toolCache = getPlatformToolCache(platform)
   return path.join(toolCache, 'Ruby', version, 'x64')
 }
 
@@ -51181,7 +51191,7 @@ async function setupRuby(options = {}) {
   const [engine, parsedVersion] = parseRubyEngineAndVersion(inputs['ruby-version'])
 
   let installer
-  if (platform === 'windows-latest' && engine === 'ruby') {
+  if (platform.startsWith('windows-') && engine === 'ruby') {
     installer = __webpack_require__(216)
   } else {
     installer = __webpack_require__(974)
@@ -51365,9 +51375,9 @@ async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefi
     bundlerVersion = '1'
   }
 
-  if (engine === 'ruby' && common.isHeadVersion(rubyVersion) && bundlerVersion === '2') {
+  if ((engine === 'ruby' || engine === 'truffleruby') && common.isHeadVersion(rubyVersion) && bundlerVersion === '2') {
     console.log(`Using Bundler 2 shipped with ${engine}-${rubyVersion}`)
-  } else if (engine === 'truffleruby' && bundlerVersion === '1') {
+  } else if (engine === 'truffleruby' && !common.isHeadVersion(rubyVersion) && bundlerVersion === '1') {
     console.log(`Using Bundler 1 shipped with ${engine}`)
   } else {
     const gem = path.join(rubyPrefix, 'bin', 'gem')
@@ -52901,7 +52911,7 @@ async function install(platform, engine, version) {
 async function downloadAndExtract(platform, engine, version) {
   let rubyPrefix
   if (common.shouldExtractInToolCache(engine, version)) {
-    rubyPrefix = common.getToolCacheRubyPrefix(version)
+    rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
   } else if (windows) {
     rubyPrefix = path.join(`${common.drive}:`, `${engine}-${version}`)
   } else {

index.js

@@ -39,7 +39,7 @@ export async function setupRuby(options = {}) {
   const [engine, parsedVersion] = parseRubyEngineAndVersion(inputs['ruby-version'])
 
   let installer
-  if (platform === 'windows-latest' && engine === 'ruby') {
+  if (platform.startsWith('windows-') && engine === 'ruby') {
     installer = require('./windows')
   } else {
     installer = require('./ruby-builder')
@@ -223,9 +223,9 @@ async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefi
     bundlerVersion = '1'
   }
 
-  if (engine === 'ruby' && common.isHeadVersion(rubyVersion) && bundlerVersion === '2') {
+  if ((engine === 'ruby' || engine === 'truffleruby') && common.isHeadVersion(rubyVersion) && bundlerVersion === '2') {
     console.log(`Using Bundler 2 shipped with ${engine}-${rubyVersion}`)
-  } else if (engine === 'truffleruby' && bundlerVersion === '1') {
+  } else if (engine === 'truffleruby' && !common.isHeadVersion(rubyVersion) && bundlerVersion === '1') {
     console.log(`Using Bundler 1 shipped with ${engine}`)
   } else {
     const gem = path.join(rubyPrefix, 'bin', 'gem')

ruby-builder.js

@@ -23,7 +23,7 @@ export async function install(platform, engine, version) {
 async function downloadAndExtract(platform, engine, version) {
   let rubyPrefix
   if (common.shouldExtractInToolCache(engine, version)) {
-    rubyPrefix = common.getToolCacheRubyPrefix(version)
+    rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
   } else if (windows) {
     rubyPrefix = path.join(`${common.drive}:`, `${engine}-${version}`)
   } else {

windows.js

@@ -38,7 +38,7 @@ export async function install(platform, engine, version) {
 
   let rubyPrefix
   if (common.shouldExtractInToolCache(engine, version)) {
-    rubyPrefix = common.getToolCacheRubyPrefix(version)
+    rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
   } else {
     rubyPrefix = `${drive}:\\${base}`
   }