Add 3.0.0-preview2

* So the mapping to `engine-version` versions is clearer.

.github/workflows/test.yml

@@ -15,20 +15,23 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-16.04, ubuntu-18.04, ubuntu-20.04, macos-10.15, windows-2016, windows-2019 ]
+        os: [ ubuntu-16.04, ubuntu-18.04, ubuntu-20.04, macos-10.15, macos-11.0, windows-2016, windows-2019 ]
         # Use various version syntax here for testing
-        ruby: [ 2.1, 2.2, 2.3, 2.4, 2.5, 2.6.6, 2.7, ruby-head, debug, jruby-9.1, jruby, jruby-head, truffleruby, truffleruby-head ]
+        ruby: [ 2.1, 2.2, 2.3, 2.4, 2.5, 2.6.6, 2.7, '3.0', ruby-head, debug, jruby-9.1, jruby, jruby-head, truffleruby, truffleruby-head ]
         include:
         - { os: windows-2016, ruby: mingw }
         - { os: windows-2019, ruby: mingw }
         - { os: windows-2019, ruby: mswin }
         exclude:
+        - { os: windows-2016, ruby: '3.0' }
         - { os: windows-2016, ruby: debug }
         - { os: windows-2016, ruby: truffleruby }
         - { os: windows-2016, ruby: truffleruby-head }
+        - { os: windows-2019, ruby: '3.0' }
         - { os: windows-2019, ruby: debug }
         - { os: windows-2019, ruby: truffleruby }
         - { os: windows-2019, ruby: truffleruby-head }
+        - { os: macos-11.0, ruby: truffleruby }
 
     name: ${{ matrix.os }} ${{ matrix.ruby }}
     runs-on: ${{ matrix.os }}
@@ -100,7 +103,7 @@ jobs:
       run: gem install sassc -N
 
   lint:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v2
     - run: yarn install

README.md

@@ -14,9 +14,9 @@ This action currently supports these versions of MRI, JRuby and TruffleRuby:
 
 | Interpreter | Versions |
 | ----------- | -------- |
-| Ruby | 2.1.9, 2.2, 2.3.0 - 2.3.8, 2.4.0 - 2.4.10, 2.5.0 - 2.5.8, 2.6.0 - 2.6.6, 2.7.2, head, debug, mingw, mswin |
+| `ruby` | 2.1.9, 2.2, 2.3.0 - 2.3.8, 2.4.0 - 2.4.10, 2.5.0 - 2.5.8, 2.6.0 - 2.6.6, 2.7.2, head, debug, mingw, mswin |
-| JRuby | 9.1.17.0, 9.2.9.0 - 9.2.13.0, head |
+| `jruby` | 9.1.17.0, 9.2.9.0 - 9.2.13.0, head |
-| TruffleRuby | 19.3.0 - 20.2.0, head |
+| `truffleruby` | 19.3.0 - 20.3.0, head |
 
 `ruby-debug` is the same as `ruby-head` but with assertions enabled (`-DRUBY_DEBUG=1`).  
 On Windows, `mingw` and `mswin` are `ruby-head` builds using the MSYS2/MinGW and the MSVC toolchains respectively.
@@ -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,
+Note that Ruby ≤ 2.4 and the OpenSSL version it needs (1.0.2) are both end-of-life,
-which means Ruby ≤ 2.3 is unmaintained and considered insecure.
+which means Ruby ≤ 2.4 is unmaintained and considered insecure.
-On Windows, Ruby 2.4 uses OpenSSL 1.0.2, which is no longer maintained.
 
 ### Supported Platforms
 
@@ -40,7 +39,7 @@ The action works for all [GitHub-hosted runners](https://help.github.com/en/acti
 | Operating System | Recommended | Other Supported Versions |
 | ----------- | -------- | -------- |
 | Ubuntu  | `ubuntu-latest`  (= `ubuntu-18.04`) | `ubuntu-20.04`, `ubuntu-16.04` |
-| macOS   | `macos-latest`   (= `macos-10.15`)  | |
+| macOS   | `macos-latest`   (= `macos-10.15`)  | `macos-11.0` |
 | Windows | `windows-latest` (= `windows-2019`) | `windows-2016` |
 
 The prebuilt releases are generated by [ruby-builder](https://github.com/ruby/ruby-builder)
@@ -68,7 +67,6 @@ jobs:
       with:
         ruby-version: 2.6 # Not needed with a .ruby-version file
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
-    - run: bundle install
     - run: bundle exec rake
 ```
 
@@ -87,14 +85,12 @@ jobs:
         os: [ubuntu, macos]
         ruby: [2.5, 2.6, 2.7, head, debug, jruby, jruby-head, truffleruby, truffleruby-head]
     runs-on: ${{ matrix.os }}-latest
-    continue-on-error: ${{ endsWith(matrix.ruby, 'head') || matrix.ruby == 'debug' }}
     steps:
     - uses: actions/checkout@v2
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
-    - run: bundle install
     - run: bundle exec rake
 ```
 
@@ -140,38 +136,26 @@ This caching speeds up installing gems significantly and avoids too many request
 It needs a `Gemfile` (or `$BUNDLE_GEMFILE` or `gems.rb`) under the [`working-directory`](#working-directory).  
 If there is a `Gemfile.lock` (or `$BUNDLE_GEMFILE.lock` or `gems.locked`), `bundle config --local deployment true` is used.
 
+To use a `Gemfile` which is not at the root or has a different name, set `BUNDLE_GEMFILE` in the `env` at the job level, so it is set for all steps:
+```yaml
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    env:
+      BUNDLE_GEMFILE: subdir/mygemfile
+    steps:
+    - uses: actions/checkout@v2
+    - uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: 2.6
+        bundler-cache: true
+    - run: bundle exec rake
+```
+Of course you can also use a matrix of gemfiles if you need to test multiple gemfiles.
+
 To perform caching, this action will use `bundle config --local path vendor/bundle`.  
 Therefore, the Bundler `path` should not be changed in your workflow for the cache to work (no `bundle config path`).
 
-### Caching `bundle install` manually
-
-You can also cache gems manually,
-but this is not recommended because it is verbose and very difficult to use a correct cache key.
-You can cache the installed gems with these two steps:
-
-```yaml
-    - uses: actions/cache@v2
-      with:
-        path: vendor/bundle
-        key: bundle-use-ruby-${{ matrix.os }}-${{ matrix.ruby }}-${{ hashFiles('**/Gemfile.lock') }}
-        restore-keys: |
-          bundle-use-ruby-${{ matrix.os }}-${{ matrix.ruby }}-
-    - name: bundle install
-      run: |
-        bundle config deployment true
-        bundle config path vendor/bundle
-        bundle install --jobs 4
-```
-
-When using a single OS, replace `${{ matrix.os }}` with the OS.  
-When using a single job with a Ruby version, replace `${{ matrix.ruby }}` with the Ruby version.  
-When using `.ruby-version`, replace `${{ matrix.ruby }}` with `${{ hashFiles('.ruby-version') }}`.  
-When using `.tool-versions`, replace `${{ matrix.ruby }}` with `${{ hashFiles('.tool-versions') }}`.
-
-This uses the [cache action](https://github.com/actions/cache).
-The code above is a more complete version of the [Ruby - Bundler example](https://github.com/actions/cache/blob/master/examples.md#ruby---bundler).
-Make sure to include `use-ruby` in the `key` to avoid conflicting with previous caches.
-
 ## Windows
 
 Note that running CI on Windows can be quite challenging if you are not very familiar with Windows.
@@ -202,9 +186,13 @@ This action might work with [self-hosted runners](https://docs.github.com/en/act
 if the [virtual environment](https://github.com/actions/virtual-environments) is very similar to the ones used by GitHub runners. Notably:
 
 * Make sure to use the same operating system and version.
+* Set the environment variable `ImageOS` to the corresponding value on GitHub-hosted runners (e.g. `ubuntu18`/`macos1015`/`win19`). This is necessary to detect the 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

@@ -11,6 +11,14 @@ export const windows = (os.platform() === 'win32')
 // Extract to SSD on Windows, see https://github.com/ruby/setup-ruby/pull/14
 export const drive = (windows ? (process.env['GITHUB_WORKSPACE'] || 'C')[0] : undefined)
 
+export function partition(string, separator) {
+  const i = string.indexOf(separator)
+  if (i === -1) {
+    throw new Error(`No separator ${separator} in string ${string}`)
+  }
+  return [string.slice(0, i), string.slice(i + separator.length, string.length)]
+}
+
 export async function measure(name, block) {
   return await core.group(name, async () => {
     const start = performance.now()
@@ -28,6 +36,10 @@ export function isHeadVersion(rubyVersion) {
   return rubyVersion === 'head' || rubyVersion === 'debug' || rubyVersion === 'mingw' || rubyVersion === 'mswin'
 }
 
+export function isStableVersion(rubyVersion) {
+  return /^\d+(\.\d+)*$/.test(rubyVersion)
+}
+
 export async function hashFile(file) {
   // See https://github.com/actions/runner/blob/master/src/Misc/expressionFunc/hashFiles/src/hashFiles.ts
   const hash = crypto.createHash('sha256')
@@ -36,46 +48,67 @@ export async function hashFile(file) {
   return hash.digest('hex')
 }
 
+function getImageOS() {
+  const imageOS = process.env['ImageOS']
+  if (!imageOS) {
+    throw new Error('The environment variable ImageOS must be set')
+  }
+  return imageOS
+}
+
 export function getVirtualEnvironmentName() {
-  const platform = os.platform()
+  const imageOS = getImageOS()
-  if (platform === 'linux') {
-    return `ubuntu-${findUbuntuVersion()}`
-  } else if (platform === 'darwin') {
-    return 'macos-latest'
-  } else if (platform === 'win32') {
-    return 'windows-latest'
-  } else {
-    throw new Error(`Unknown platform ${platform}`)
-  }
-}
 
-function findUbuntuVersion() {
+  let match = imageOS.match(/^ubuntu(\d+)/) // e.g. ubuntu18
-  const lsb_release = fs.readFileSync('/etc/lsb-release', 'utf8')
-  const match = lsb_release.match(/^DISTRIB_RELEASE=(\d+\.\d+)$/m)
   if (match) {
-    return match[1]
+    return `ubuntu-${match[1]}.04`
-  } else {
-    throw new Error('Could not find Ubuntu version')
   }
+
+  match = imageOS.match(/^macos(\d{2})(\d+)?/) // e.g. macos1015, macos11
+  if (match) {
+    return `macos-${match[1]}.${match[2] || '0'}`
+  }
+
+  match = imageOS.match(/^win(\d+)/) // e.g. win19
+  if (match) {
+    return `windows-20${match[1]}`
+  }
+
+  throw new Error(`Unknown ImageOS ${imageOS}`)
 }
 
-export function shouldExtractInToolCache(engine, version) {
+export function shouldUseToolCache(engine, version) {
   return engine === 'ruby' && !isHeadVersion(version)
 }
 
-export function getToolCacheRubyPrefix(version) {
+function getPlatformToolCache(platform) {
-  const toolCache = process.env['RUNNER_TOOL_CACHE']
+  // Hardcode paths rather than using $RUNNER_TOOL_CACHE because the prebuilt Rubies cannot be moved anyway
-  if (!toolCache) {
+  if (platform.startsWith('ubuntu-')) {
-    throw new Error('$RUNNER_TOOL_CACHE must be set')
+    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')
 }
 
+export function createToolCacheCompleteFile(toolCacheRubyPrefix) {
+  const completeFile = `${toolCacheRubyPrefix}.complete`
+  fs.writeFileSync(completeFile, '')
+}
+
 // convert windows path like C:\Users\runneradmin to /c/Users/runneradmin
 export function win2nix(path) {
   if (/^[A-Z]:/i.test(path)) {
     // path starts with drive
-    path = `/${path[0].toLowerCase()}${path.split(':', 2)[1]}`
+    path = `/${path[0].toLowerCase()}${partition(path, ':')[1]}`
   }
   return path.replace(/\\/g, '/').replace(/ /g, '\\ ')
 }

dist/index.js

@@ -27712,18 +27712,32 @@ async function install(platform, engine, version) {
   }
   const base = url.slice(url.lastIndexOf('/') + 1, url.length - '.7z'.length)
 
-  let rubyPrefix
+  let rubyPrefix, inToolCache
-  if (common.shouldExtractInToolCache(engine, version)) {
+  if (common.shouldUseToolCache(engine, version)) {
-    rubyPrefix = common.getToolCacheRubyPrefix(version)
+    inToolCache = tc.find('Ruby', version)
+    if (inToolCache) {
+      rubyPrefix = inToolCache
+    } else {
+      rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
+    }
   } else {
     rubyPrefix = `${drive}:\\${base}`
   }
-  const parentDir = path.dirname(rubyPrefix)
 
   let toolchainPaths = (version === 'mswin') ? await setupMSWin() : await setupMingw(version)
 
   common.setupPath([`${rubyPrefix}\\bin`, ...toolchainPaths])
 
+  if (!inToolCache) {
+    await downloadAndExtract(engine, version, url, base, rubyPrefix);
+  }
+
+  return rubyPrefix
+}
+
+async function downloadAndExtract(engine, version, url, base, rubyPrefix) {
+  const parentDir = path.dirname(rubyPrefix)
+
   const downloadPath = await common.measure('Downloading Ruby', async () => {
     console.log(url)
     return await tc.downloadTool(url)
@@ -27736,7 +27750,9 @@ async function install(platform, engine, version) {
     await io.mv(path.join(parentDir, base), rubyPrefix)
   }
 
-  return rubyPrefix
+  if (common.shouldUseToolCache(engine, version)) {
+    common.createToolCacheCompleteFile(rubyPrefix)
+  }
 }
 
 async function setupMingw(version) {
@@ -27796,7 +27812,7 @@ function addVCVARSEnv() {
   let newSet = cp.execSync(cmd).toString().trim().split(/\r?\n/)
   newSet = newSet.filter(line => line.match(/\S=\S/))
   newSet.forEach(s => {
-    let [k,v] = s.split('=', 2)
+    let [k,v] = common.partition(s, '=')
     newEnv.set(k,v)
   })
 
@@ -32094,12 +32110,15 @@ exports.default = _default;
 __webpack_require__.r(__webpack_exports__);
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "windows", function() { return windows; });
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "drive", function() { return drive; });
+/* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "partition", function() { return partition; });
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "measure", function() { return measure; });
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "isHeadVersion", function() { return isHeadVersion; });
+/* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "isStableVersion", function() { return isStableVersion; });
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "hashFile", function() { return hashFile; });
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "getVirtualEnvironmentName", function() { return getVirtualEnvironmentName; });
-/* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "shouldExtractInToolCache", function() { return shouldExtractInToolCache; });
+/* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "shouldUseToolCache", function() { return shouldUseToolCache; });
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "getToolCacheRubyPrefix", function() { return getToolCacheRubyPrefix; });
+/* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "createToolCacheCompleteFile", function() { return createToolCacheCompleteFile; });
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "win2nix", function() { return win2nix; });
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "setupPath", function() { return setupPath; });
 const os = __webpack_require__(87)
@@ -32115,6 +32134,14 @@ const windows = (os.platform() === 'win32')
 // Extract to SSD on Windows, see https://github.com/ruby/setup-ruby/pull/14
 const drive = (windows ? (process.env['GITHUB_WORKSPACE'] || 'C')[0] : undefined)
 
+function partition(string, separator) {
+  const i = string.indexOf(separator)
+  if (i === -1) {
+    throw new Error(`No separator ${separator} in string ${string}`)
+  }
+  return [string.slice(0, i), string.slice(i + separator.length, string.length)]
+}
+
 async function measure(name, block) {
   return await core.group(name, async () => {
     const start = performance.now()
@@ -32132,6 +32159,10 @@ function isHeadVersion(rubyVersion) {
   return rubyVersion === 'head' || rubyVersion === 'debug' || rubyVersion === 'mingw' || rubyVersion === 'mswin'
 }
 
+function isStableVersion(rubyVersion) {
+  return /^\d+(\.\d+)*$/.test(rubyVersion)
+}
+
 async function hashFile(file) {
   // See https://github.com/actions/runner/blob/master/src/Misc/expressionFunc/hashFiles/src/hashFiles.ts
   const hash = crypto.createHash('sha256')
@@ -32140,46 +32171,67 @@ async function hashFile(file) {
   return hash.digest('hex')
 }
 
+function getImageOS() {
+  const imageOS = process.env['ImageOS']
+  if (!imageOS) {
+    throw new Error('The environment variable ImageOS must be set')
+  }
+  return imageOS
+}
+
 function getVirtualEnvironmentName() {
-  const platform = os.platform()
+  const imageOS = getImageOS()
-  if (platform === 'linux') {
-    return `ubuntu-${findUbuntuVersion()}`
-  } else if (platform === 'darwin') {
-    return 'macos-latest'
-  } else if (platform === 'win32') {
-    return 'windows-latest'
-  } else {
-    throw new Error(`Unknown platform ${platform}`)
-  }
-}
 
-function findUbuntuVersion() {
+  let match = imageOS.match(/^ubuntu(\d+)/) // e.g. ubuntu18
-  const lsb_release = fs.readFileSync('/etc/lsb-release', 'utf8')
-  const match = lsb_release.match(/^DISTRIB_RELEASE=(\d+\.\d+)$/m)
   if (match) {
-    return match[1]
+    return `ubuntu-${match[1]}.04`
-  } else {
-    throw new Error('Could not find Ubuntu version')
   }
+
+  match = imageOS.match(/^macos(\d{2})(\d+)?/) // e.g. macos1015, macos11
+  if (match) {
+    return `macos-${match[1]}.${match[2] || '0'}`
+  }
+
+  match = imageOS.match(/^win(\d+)/) // e.g. win19
+  if (match) {
+    return `windows-20${match[1]}`
+  }
+
+  throw new Error(`Unknown ImageOS ${imageOS}`)
 }
 
-function shouldExtractInToolCache(engine, version) {
+function shouldUseToolCache(engine, version) {
   return engine === 'ruby' && !isHeadVersion(version)
 }
 
-function getToolCacheRubyPrefix(version) {
+function getPlatformToolCache(platform) {
-  const toolCache = process.env['RUNNER_TOOL_CACHE']
+  // Hardcode paths rather than using $RUNNER_TOOL_CACHE because the prebuilt Rubies cannot be moved anyway
-  if (!toolCache) {
+  if (platform.startsWith('ubuntu-')) {
-    throw new Error('$RUNNER_TOOL_CACHE must be set')
+    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')
 }
 
+function createToolCacheCompleteFile(toolCacheRubyPrefix) {
+  const completeFile = `${toolCacheRubyPrefix}.complete`
+  fs.writeFileSync(completeFile, '')
+}
+
 // convert windows path like C:\Users\runneradmin to /c/Users/runneradmin
 function win2nix(path) {
   if (/^[A-Z]:/i.test(path)) {
     // path starts with drive
-    path = `/${path[0].toLowerCase()}${path.split(':', 2)[1]}`
+    path = `/${path[0].toLowerCase()}${partition(path, ':')[1]}`
   }
   return path.replace(/\\/g, '/').replace(/ /g, '\\ ')
 }
@@ -44510,7 +44562,7 @@ function getVersions(platform) {
       "2.5.0", "2.5.1", "2.5.2", "2.5.3", "2.5.4", "2.5.5", "2.5.6", "2.5.7", "2.5.8",
       "2.6.0", "2.6.1", "2.6.2", "2.6.3", "2.6.4", "2.6.5", "2.6.6",
       "2.7.0", "2.7.1", "2.7.2",
-      "3.0.0-preview1",
+      "3.0.0-preview1", "3.0.0-preview2",
       "head", "debug",
     ],
     "jruby": [
@@ -44520,7 +44572,7 @@ function getVersions(platform) {
     ],
     "truffleruby": [
       "19.3.0", "19.3.1",
-      "20.0.0", "20.1.0", "20.2.0",
+      "20.0.0", "20.1.0", "20.2.0", "20.3.0",
       "head"
     ]
   }
@@ -51181,7 +51233,7 @@ 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)
@@ -51205,37 +51257,27 @@ async function setupRuby(options = {}) {
   if (inputs['bundler'] !== 'none') {
     const [gemfile, lockFile] = detectGemfiles()
 
-    await common.measure('Installing Bundler', async () =>
+    const bundlerVersion = await common.measure('Installing Bundler', async () =>
       installBundler(inputs['bundler'], lockFile, platform, rubyPrefix, engine, version))
 
     if (inputs['bundler-cache'] === 'true') {
       await common.measure('bundle install', async () =>
-          bundleInstall(gemfile, lockFile, platform, engine, version))
+          bundleInstall(gemfile, lockFile, platform, engine, version, bundlerVersion))
     }
   }
 
   core.setOutput('ruby-prefix', rubyPrefix)
 }
 
+// The returned gemfile is guaranteed to exist, the lockfile might not exist
 function detectGemfiles() {
   const gemfilePath = process.env['BUNDLE_GEMFILE'] || 'Gemfile'
   if (fs.existsSync(gemfilePath)) {
-    const lockPath = `${gemfilePath}.lock`
+    return [gemfilePath, `${gemfilePath}.lock`]
-    if (fs.existsSync(lockPath)) {
-      return [gemfilePath, lockPath]
-    } else {
-      return [gemfilePath, null]
-    }
   }
 
-  const gemsRbPath = "gems.rb"
+  if (fs.existsSync("gems.rb")) {
-  if (fs.existsSync(gemsRbPath)) {
+    return ["gems.rb", "gems.locked"]
-    const lockPath = "gems.locked"
-    if (fs.existsSync(lockPath)) {
-      return [gemsRbPath, lockPath]
-    } else {
-      return [gemsRbPath, null]
-    }
   }
 
   return [null, null]
@@ -51258,7 +51300,7 @@ function parseRubyEngineAndVersion(rubyVersion) {
   } else if (rubyVersion === '.tool-versions') { // Read from .tool-versions
     const toolVersions = fs.readFileSync('.tool-versions', 'utf8').trim()
     const rubyLine = toolVersions.split(/\r?\n/).filter(e => e.match(/^ruby\s/))[0]
-    rubyVersion = rubyLine.split(/\s+/, 2)[1]
+    rubyVersion = rubyLine.match(/^ruby\s+(.+)$/)[1]
     console.log(`Using ${rubyVersion} as input from file .tool-versions`)
   }
 
@@ -51270,7 +51312,7 @@ function parseRubyEngineAndVersion(rubyVersion) {
     engine = rubyVersion
     version = '' // Let the logic in validateRubyEngineAndVersion() find the version
   } else { // engine-X.Y.Z
-    [engine, version] = rubyVersion.split('-', 2)
+    [engine, version] = common.partition(rubyVersion, '-')
   }
 
   return [engine, version]
@@ -51284,7 +51326,13 @@ function validateRubyEngineAndVersion(platform, engineVersions, engine, parsedVe
   let version = parsedVersion
   if (!engineVersions.includes(parsedVersion)) {
     const latestToFirstVersion = engineVersions.slice().reverse()
-    const found = latestToFirstVersion.find(v => !common.isHeadVersion(v) && v.startsWith(parsedVersion))
+    // Try to match stable versions first, so an empty version (engine-only) matches the latest stable version
+    let found = latestToFirstVersion.find(v => common.isStableVersion(v) && v.startsWith(parsedVersion))
+    if (!found) {
+      // Exclude head versions, they must be exact matches
+      found = latestToFirstVersion.find(v => !common.isHeadVersion(v) && v.startsWith(parsedVersion))
+    }
+
     if (found) {
       version = found
     } else {
@@ -51319,7 +51367,7 @@ function envPreInstall() {
 }
 
 function readBundledWithFromGemfileLock(lockFile) {
-  if (lockFile !== null) {
+  if (lockFile !== null && fs.existsSync(lockFile)) {
     const contents = fs.readFileSync(lockFile, 'utf8')
     const lines = contents.split(/\r?\n/)
     const bundledWithLine = lines.findIndex(line => /^BUNDLED WITH$/.test(line.trim()))
@@ -51357,51 +51405,57 @@ async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefi
     throw new Error(`Cannot parse bundler input: ${bundlerVersion}`)
   }
 
-  if (rubyVersion.match(/^2\.[12]/)) {
+  if (engine === 'ruby' && rubyVersion.match(/^2\.[12]/)) {
     console.log('Bundler 2 requires Ruby 2.3+, using Bundler 1 on Ruby <= 2.2')
     bundlerVersion = '1'
-  } else if (rubyVersion.startsWith('2.3')) {
+  } else if (engine === 'ruby' && rubyVersion.startsWith('2.3')) {
     console.log('Ruby 2.3 has a bug with Bundler 2 (https://github.com/rubygems/rubygems/issues/3570), using Bundler 1 instead on Ruby 2.3')
     bundlerVersion = '1'
+  } else if (engine === 'jruby' && rubyVersion.startsWith('9.1.')) { // JRuby 9.1 targets Ruby 2.3, treat it the same
+    console.log('JRuby 9.1 has a bug with Bundler 2 (https://github.com/ruby/setup-ruby/issues/108), using Bundler 1 instead on JRuby 9.1')
+    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')
     await exec.exec(gem, ['install', 'bundler', '-v', `~> ${bundlerVersion}`, '--no-document'])
   }
+
+  return bundlerVersion
 }
 
-async function bundleInstall(gemfile, lockFile, platform, engine, version) {
+async function bundleInstall(gemfile, lockFile, platform, engine, rubyVersion, bundlerVersion) {
   if (gemfile === null) {
     console.log('Could not determine gemfile path, skipping "bundle install" and caching')
     return false
   }
 
+  // Before the lockfile exists, we need to specify which Bundler version to use explicitly
+  const optionsWithBundlerVersion = { env: { ...process.env, BUNDLER_VERSION: bundlerVersion } }
+
   // config
   const path = 'vendor/bundle'
 
-  if (lockFile !== null) {
+  await exec.exec('bundle', ['config', '--local', 'path', path], optionsWithBundlerVersion)
-    await exec.exec('bundle', ['config', '--local', 'deployment', 'true'])
+
+  if (fs.existsSync(lockFile)) {
+    await exec.exec('bundle', ['config', '--local', 'deployment', 'true'], optionsWithBundlerVersion)
+  } else {
+    // Generate the lockfile so we can use it to compute the cache key.
+    // This will also automatically pick up the latest gem versions compatible with the Gemfile.
+    await exec.exec('bundle', ['lock'], optionsWithBundlerVersion)
   }
-  await exec.exec('bundle', ['config', '--local', 'path', path])
 
   // cache key
   const paths = [path]
-  const baseKey = await computeBaseKey(platform, engine, version, gemfile)
+  const baseKey = await computeBaseKey(platform, engine, rubyVersion, lockFile)
-  let key = baseKey
+  const key = `${baseKey}-${await common.hashFile(lockFile)}`
-  let restoreKeys
+  // If only Gemfile.lock changes we can reuse part of the cache, and clean old gem versions below
-  if (lockFile !== null) {
+  const restoreKeys = [`${baseKey}-`]
-    key += `-${lockFile}-${await common.hashFile(lockFile)}`
-    // If only Gemfile.lock changes we can reuse part of the cache (but it will keep old gem versions in the cache)
-    restoreKeys = [`${baseKey}-${lockFile}-`]
-  } else {
-    // Only exact key, to never mix native gems of different platforms or Ruby versions
-    restoreKeys = []
-  }
   console.log(`Cache key: ${key}`)
 
   // restore cache & install
@@ -51420,14 +51474,14 @@ async function bundleInstall(gemfile, lockFile, platform, engine, version) {
     console.log(`Found cache for key: ${cachedKey}`)
   }
 
-  let alreadyInstalled = false
+  // Always run 'bundle install' to list the gems
-  if (cachedKey === key) {
+  await exec.exec('bundle', ['install', '--jobs', '4'])
-    const exitCode = await exec.exec('bundle', ['check'], { ignoreReturnCode: true })
-    alreadyInstalled = (exitCode === 0)
-  }
 
-  if (!alreadyInstalled) {
+  // @actions/cache only allows to save for non-existing keys
-    await exec.exec('bundle', ['install', '--jobs', '4'])
+  if (cachedKey !== key) {
+    if (cachedKey) { // existing cache but Gemfile.lock differs, clean old gems
+      await exec.exec('bundle', ['clean'])
+    }
 
     // Error handling from https://github.com/actions/cache/blob/master/src/save.ts
     console.log('Saving cache')
@@ -51447,8 +51501,9 @@ async function bundleInstall(gemfile, lockFile, platform, engine, version) {
   return true
 }
 
-async function computeBaseKey(platform, engine, version, gemfile) {
+async function computeBaseKey(platform, engine, version, lockFile) {
-  let baseKey = `setup-ruby-toolcache-bundle-install-${platform}-${engine}-${version}-${gemfile}`
+  let key = `setup-ruby-bundler-cache-v2-${platform}-${engine}-${version}`
+
   if (engine !== 'jruby' && common.isHeadVersion(version)) {
     let revision = '';
     await exec.exec('ruby', ['-e', 'print RUBY_REVISION'], {
@@ -51459,9 +51514,11 @@ async function computeBaseKey(platform, engine, version, gemfile) {
         }
       }
     });
-    baseKey += `-revision-${revision}`
+    key += `-revision-${revision}`
   }
-  return baseKey
+
+  key += `-${lockFile}`
+  return key
 }
 
 if (__filename.endsWith('index.js')) { run() }
@@ -52878,7 +52935,6 @@ __webpack_require__.r(__webpack_exports__);
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "install", function() { return install; });
 const os = __webpack_require__(87)
 const path = __webpack_require__(622)
-const core = __webpack_require__(186)
 const exec = __webpack_require__(514)
 const io = __webpack_require__(436)
 const tc = __webpack_require__(188)
@@ -52895,24 +52951,33 @@ function getAvailableVersions(platform, engine) {
 }
 
 async function install(platform, engine, version) {
-  return await downloadAndExtract(platform, engine, version)
+  let rubyPrefix, inToolCache
-}
+  if (common.shouldUseToolCache(engine, version)) {
-
+    inToolCache = tc.find('Ruby', version)
-async function downloadAndExtract(platform, engine, version) {
+    if (inToolCache) {
-  let rubyPrefix
+      rubyPrefix = inToolCache
-  if (common.shouldExtractInToolCache(engine, version)) {
+    } else {
-    rubyPrefix = common.getToolCacheRubyPrefix(version)
+      rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
+    }
   } else if (windows) {
     rubyPrefix = path.join(`${common.drive}:`, `${engine}-${version}`)
   } else {
     rubyPrefix = path.join(os.homedir(), '.rubies', `${engine}-${version}`)
   }
 
-  const parentDir = path.dirname(rubyPrefix)
-
   // Set the PATH now, so the MSYS2 'tar' is in Path on Windows
   common.setupPath([path.join(rubyPrefix, 'bin')])
 
+  if (!inToolCache) {
+    await downloadAndExtract(platform, engine, version, rubyPrefix);
+  }
+
+  return rubyPrefix
+}
+
+async function downloadAndExtract(platform, engine, version, rubyPrefix) {
+  const parentDir = path.dirname(rubyPrefix)
+
   await io.rmRF(rubyPrefix)
   await io.mkdirP(parentDir)
 
@@ -52925,20 +52990,29 @@ async function downloadAndExtract(platform, engine, version) {
   await common.measure('Extracting Ruby', async () => {
     if (windows) {
       // Windows 2016 doesn't have system tar, use MSYS2's, it needs unix style paths
-      await exec.exec('tar', [ '-xz', '-C', common.win2nix(parentDir), '-f', common.win2nix(downloadPath) ])
+      await exec.exec('tar', ['-xz', '-C', common.win2nix(parentDir), '-f', common.win2nix(downloadPath)])
     } else {
-      await exec.exec('tar', [ '-xz', '-C', parentDir, '-f',  downloadPath ])
+      await exec.exec('tar', ['-xz', '-C', parentDir, '-f', downloadPath])
     }
   })
 
-  return rubyPrefix
+  if (common.shouldUseToolCache(engine, version)) {
+    common.createToolCacheCompleteFile(rubyPrefix)
+  }
 }
 
 function getDownloadURL(platform, engine, version) {
+  let builderPlatform = platform
+  if (platform.startsWith('windows-')) {
+    builderPlatform = 'windows-latest'
+  } else if (platform.startsWith('macos-')) {
+    builderPlatform = 'macos-latest'
+  }
+
   if (common.isHeadVersion(version)) {
-    return getLatestHeadBuildURL(platform, engine, version)
+    return getLatestHeadBuildURL(builderPlatform, engine, version)
   } else {
-    return `${releasesURL}/download/${builderReleaseTag}/${engine}-${version}-${platform}.tar.gz`
+    return `${releasesURL}/download/${builderReleaseTag}/${engine}-${version}-${builderPlatform}.tar.gz`
   }
 }
 

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')
@@ -63,37 +63,27 @@ export async function setupRuby(options = {}) {
   if (inputs['bundler'] !== 'none') {
     const [gemfile, lockFile] = detectGemfiles()
 
-    await common.measure('Installing Bundler', async () =>
+    const bundlerVersion = await common.measure('Installing Bundler', async () =>
       installBundler(inputs['bundler'], lockFile, platform, rubyPrefix, engine, version))
 
     if (inputs['bundler-cache'] === 'true') {
       await common.measure('bundle install', async () =>
-          bundleInstall(gemfile, lockFile, platform, engine, version))
+          bundleInstall(gemfile, lockFile, platform, engine, version, bundlerVersion))
     }
   }
 
   core.setOutput('ruby-prefix', rubyPrefix)
 }
 
+// The returned gemfile is guaranteed to exist, the lockfile might not exist
 function detectGemfiles() {
   const gemfilePath = process.env['BUNDLE_GEMFILE'] || 'Gemfile'
   if (fs.existsSync(gemfilePath)) {
-    const lockPath = `${gemfilePath}.lock`
+    return [gemfilePath, `${gemfilePath}.lock`]
-    if (fs.existsSync(lockPath)) {
-      return [gemfilePath, lockPath]
-    } else {
-      return [gemfilePath, null]
-    }
   }
 
-  const gemsRbPath = "gems.rb"
+  if (fs.existsSync("gems.rb")) {
-  if (fs.existsSync(gemsRbPath)) {
+    return ["gems.rb", "gems.locked"]
-    const lockPath = "gems.locked"
-    if (fs.existsSync(lockPath)) {
-      return [gemsRbPath, lockPath]
-    } else {
-      return [gemsRbPath, null]
-    }
   }
 
   return [null, null]
@@ -116,7 +106,7 @@ function parseRubyEngineAndVersion(rubyVersion) {
   } else if (rubyVersion === '.tool-versions') { // Read from .tool-versions
     const toolVersions = fs.readFileSync('.tool-versions', 'utf8').trim()
     const rubyLine = toolVersions.split(/\r?\n/).filter(e => e.match(/^ruby\s/))[0]
-    rubyVersion = rubyLine.split(/\s+/, 2)[1]
+    rubyVersion = rubyLine.match(/^ruby\s+(.+)$/)[1]
     console.log(`Using ${rubyVersion} as input from file .tool-versions`)
   }
 
@@ -128,7 +118,7 @@ function parseRubyEngineAndVersion(rubyVersion) {
     engine = rubyVersion
     version = '' // Let the logic in validateRubyEngineAndVersion() find the version
   } else { // engine-X.Y.Z
-    [engine, version] = rubyVersion.split('-', 2)
+    [engine, version] = common.partition(rubyVersion, '-')
   }
 
   return [engine, version]
@@ -142,7 +132,13 @@ function validateRubyEngineAndVersion(platform, engineVersions, engine, parsedVe
   let version = parsedVersion
   if (!engineVersions.includes(parsedVersion)) {
     const latestToFirstVersion = engineVersions.slice().reverse()
-    const found = latestToFirstVersion.find(v => !common.isHeadVersion(v) && v.startsWith(parsedVersion))
+    // Try to match stable versions first, so an empty version (engine-only) matches the latest stable version
+    let found = latestToFirstVersion.find(v => common.isStableVersion(v) && v.startsWith(parsedVersion))
+    if (!found) {
+      // Exclude head versions, they must be exact matches
+      found = latestToFirstVersion.find(v => !common.isHeadVersion(v) && v.startsWith(parsedVersion))
+    }
+
     if (found) {
       version = found
     } else {
@@ -177,7 +173,7 @@ function envPreInstall() {
 }
 
 function readBundledWithFromGemfileLock(lockFile) {
-  if (lockFile !== null) {
+  if (lockFile !== null && fs.existsSync(lockFile)) {
     const contents = fs.readFileSync(lockFile, 'utf8')
     const lines = contents.split(/\r?\n/)
     const bundledWithLine = lines.findIndex(line => /^BUNDLED WITH$/.test(line.trim()))
@@ -215,51 +211,57 @@ async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefi
     throw new Error(`Cannot parse bundler input: ${bundlerVersion}`)
   }
 
-  if (rubyVersion.match(/^2\.[12]/)) {
+  if (engine === 'ruby' && rubyVersion.match(/^2\.[12]/)) {
     console.log('Bundler 2 requires Ruby 2.3+, using Bundler 1 on Ruby <= 2.2')
     bundlerVersion = '1'
-  } else if (rubyVersion.startsWith('2.3')) {
+  } else if (engine === 'ruby' && rubyVersion.startsWith('2.3')) {
     console.log('Ruby 2.3 has a bug with Bundler 2 (https://github.com/rubygems/rubygems/issues/3570), using Bundler 1 instead on Ruby 2.3')
     bundlerVersion = '1'
+  } else if (engine === 'jruby' && rubyVersion.startsWith('9.1.')) { // JRuby 9.1 targets Ruby 2.3, treat it the same
+    console.log('JRuby 9.1 has a bug with Bundler 2 (https://github.com/ruby/setup-ruby/issues/108), using Bundler 1 instead on JRuby 9.1')
+    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')
     await exec.exec(gem, ['install', 'bundler', '-v', `~> ${bundlerVersion}`, '--no-document'])
   }
+
+  return bundlerVersion
 }
 
-async function bundleInstall(gemfile, lockFile, platform, engine, version) {
+async function bundleInstall(gemfile, lockFile, platform, engine, rubyVersion, bundlerVersion) {
   if (gemfile === null) {
     console.log('Could not determine gemfile path, skipping "bundle install" and caching')
     return false
   }
 
+  // Before the lockfile exists, we need to specify which Bundler version to use explicitly
+  const optionsWithBundlerVersion = { env: { ...process.env, BUNDLER_VERSION: bundlerVersion } }
+
   // config
   const path = 'vendor/bundle'
 
-  if (lockFile !== null) {
+  await exec.exec('bundle', ['config', '--local', 'path', path], optionsWithBundlerVersion)
-    await exec.exec('bundle', ['config', '--local', 'deployment', 'true'])
+
+  if (fs.existsSync(lockFile)) {
+    await exec.exec('bundle', ['config', '--local', 'deployment', 'true'], optionsWithBundlerVersion)
+  } else {
+    // Generate the lockfile so we can use it to compute the cache key.
+    // This will also automatically pick up the latest gem versions compatible with the Gemfile.
+    await exec.exec('bundle', ['lock'], optionsWithBundlerVersion)
   }
-  await exec.exec('bundle', ['config', '--local', 'path', path])
 
   // cache key
   const paths = [path]
-  const baseKey = await computeBaseKey(platform, engine, version, gemfile)
+  const baseKey = await computeBaseKey(platform, engine, rubyVersion, lockFile)
-  let key = baseKey
+  const key = `${baseKey}-${await common.hashFile(lockFile)}`
-  let restoreKeys
+  // If only Gemfile.lock changes we can reuse part of the cache, and clean old gem versions below
-  if (lockFile !== null) {
+  const restoreKeys = [`${baseKey}-`]
-    key += `-${lockFile}-${await common.hashFile(lockFile)}`
-    // If only Gemfile.lock changes we can reuse part of the cache (but it will keep old gem versions in the cache)
-    restoreKeys = [`${baseKey}-${lockFile}-`]
-  } else {
-    // Only exact key, to never mix native gems of different platforms or Ruby versions
-    restoreKeys = []
-  }
   console.log(`Cache key: ${key}`)
 
   // restore cache & install
@@ -278,14 +280,14 @@ async function bundleInstall(gemfile, lockFile, platform, engine, version) {
     console.log(`Found cache for key: ${cachedKey}`)
   }
 
-  let alreadyInstalled = false
+  // Always run 'bundle install' to list the gems
-  if (cachedKey === key) {
+  await exec.exec('bundle', ['install', '--jobs', '4'])
-    const exitCode = await exec.exec('bundle', ['check'], { ignoreReturnCode: true })
-    alreadyInstalled = (exitCode === 0)
-  }
 
-  if (!alreadyInstalled) {
+  // @actions/cache only allows to save for non-existing keys
-    await exec.exec('bundle', ['install', '--jobs', '4'])
+  if (cachedKey !== key) {
+    if (cachedKey) { // existing cache but Gemfile.lock differs, clean old gems
+      await exec.exec('bundle', ['clean'])
+    }
 
     // Error handling from https://github.com/actions/cache/blob/master/src/save.ts
     console.log('Saving cache')
@@ -305,8 +307,9 @@ async function bundleInstall(gemfile, lockFile, platform, engine, version) {
   return true
 }
 
-async function computeBaseKey(platform, engine, version, gemfile) {
+async function computeBaseKey(platform, engine, version, lockFile) {
-  let baseKey = `setup-ruby-toolcache-bundle-install-${platform}-${engine}-${version}-${gemfile}`
+  let key = `setup-ruby-bundler-cache-v2-${platform}-${engine}-${version}`
+
   if (engine !== 'jruby' && common.isHeadVersion(version)) {
     let revision = '';
     await exec.exec('ruby', ['-e', 'print RUBY_REVISION'], {
@@ -317,9 +320,11 @@ async function computeBaseKey(platform, engine, version, gemfile) {
         }
       }
     });
-    baseKey += `-revision-${revision}`
+    key += `-revision-${revision}`
   }
-  return baseKey
+
+  key += `-${lockFile}`
+  return key
 }
 
 if (__filename.endsWith('index.js')) { run() }

ruby-builder-versions.js

@@ -8,7 +8,7 @@ export function getVersions(platform) {
       "2.5.0", "2.5.1", "2.5.2", "2.5.3", "2.5.4", "2.5.5", "2.5.6", "2.5.7", "2.5.8",
       "2.6.0", "2.6.1", "2.6.2", "2.6.3", "2.6.4", "2.6.5", "2.6.6",
       "2.7.0", "2.7.1", "2.7.2",
-      "3.0.0-preview1",
+      "3.0.0-preview1", "3.0.0-preview2",
       "head", "debug",
     ],
     "jruby": [
@@ -18,7 +18,7 @@ export function getVersions(platform) {
     ],
     "truffleruby": [
       "19.3.0", "19.3.1",
-      "20.0.0", "20.1.0", "20.2.0",
+      "20.0.0", "20.1.0", "20.2.0", "20.3.0",
       "head"
     ]
   }

ruby-builder.js

@@ -1,6 +1,5 @@
 const os = require('os')
 const path = require('path')
-const core = require('@actions/core')
 const exec = require('@actions/exec')
 const io = require('@actions/io')
 const tc = require('@actions/tool-cache')
@@ -17,24 +16,33 @@ export function getAvailableVersions(platform, engine) {
 }
 
 export async function install(platform, engine, version) {
-  return await downloadAndExtract(platform, engine, version)
+  let rubyPrefix, inToolCache
-}
+  if (common.shouldUseToolCache(engine, version)) {
-
+    inToolCache = tc.find('Ruby', version)
-async function downloadAndExtract(platform, engine, version) {
+    if (inToolCache) {
-  let rubyPrefix
+      rubyPrefix = inToolCache
-  if (common.shouldExtractInToolCache(engine, version)) {
+    } else {
-    rubyPrefix = common.getToolCacheRubyPrefix(version)
+      rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
+    }
   } else if (windows) {
     rubyPrefix = path.join(`${common.drive}:`, `${engine}-${version}`)
   } else {
     rubyPrefix = path.join(os.homedir(), '.rubies', `${engine}-${version}`)
   }
 
-  const parentDir = path.dirname(rubyPrefix)
-
   // Set the PATH now, so the MSYS2 'tar' is in Path on Windows
   common.setupPath([path.join(rubyPrefix, 'bin')])
 
+  if (!inToolCache) {
+    await downloadAndExtract(platform, engine, version, rubyPrefix);
+  }
+
+  return rubyPrefix
+}
+
+async function downloadAndExtract(platform, engine, version, rubyPrefix) {
+  const parentDir = path.dirname(rubyPrefix)
+
   await io.rmRF(rubyPrefix)
   await io.mkdirP(parentDir)
 
@@ -47,20 +55,29 @@ async function downloadAndExtract(platform, engine, version) {
   await common.measure('Extracting Ruby', async () => {
     if (windows) {
       // Windows 2016 doesn't have system tar, use MSYS2's, it needs unix style paths
-      await exec.exec('tar', [ '-xz', '-C', common.win2nix(parentDir), '-f', common.win2nix(downloadPath) ])
+      await exec.exec('tar', ['-xz', '-C', common.win2nix(parentDir), '-f', common.win2nix(downloadPath)])
     } else {
-      await exec.exec('tar', [ '-xz', '-C', parentDir, '-f',  downloadPath ])
+      await exec.exec('tar', ['-xz', '-C', parentDir, '-f', downloadPath])
     }
   })
 
-  return rubyPrefix
+  if (common.shouldUseToolCache(engine, version)) {
+    common.createToolCacheCompleteFile(rubyPrefix)
+  }
 }
 
 function getDownloadURL(platform, engine, version) {
+  let builderPlatform = platform
+  if (platform.startsWith('windows-')) {
+    builderPlatform = 'windows-latest'
+  } else if (platform.startsWith('macos-')) {
+    builderPlatform = 'macos-latest'
+  }
+
   if (common.isHeadVersion(version)) {
-    return getLatestHeadBuildURL(platform, engine, version)
+    return getLatestHeadBuildURL(builderPlatform, engine, version)
   } else {
-    return `${releasesURL}/download/${builderReleaseTag}/${engine}-${version}-${platform}.tar.gz`
+    return `${releasesURL}/download/${builderReleaseTag}/${engine}-${version}-${builderPlatform}.tar.gz`
   }
 }
 

windows.js

@@ -36,18 +36,32 @@ export async function install(platform, engine, version) {
   }
   const base = url.slice(url.lastIndexOf('/') + 1, url.length - '.7z'.length)
 
-  let rubyPrefix
+  let rubyPrefix, inToolCache
-  if (common.shouldExtractInToolCache(engine, version)) {
+  if (common.shouldUseToolCache(engine, version)) {
-    rubyPrefix = common.getToolCacheRubyPrefix(version)
+    inToolCache = tc.find('Ruby', version)
+    if (inToolCache) {
+      rubyPrefix = inToolCache
+    } else {
+      rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
+    }
   } else {
     rubyPrefix = `${drive}:\\${base}`
   }
-  const parentDir = path.dirname(rubyPrefix)
 
   let toolchainPaths = (version === 'mswin') ? await setupMSWin() : await setupMingw(version)
 
   common.setupPath([`${rubyPrefix}\\bin`, ...toolchainPaths])
 
+  if (!inToolCache) {
+    await downloadAndExtract(engine, version, url, base, rubyPrefix);
+  }
+
+  return rubyPrefix
+}
+
+async function downloadAndExtract(engine, version, url, base, rubyPrefix) {
+  const parentDir = path.dirname(rubyPrefix)
+
   const downloadPath = await common.measure('Downloading Ruby', async () => {
     console.log(url)
     return await tc.downloadTool(url)
@@ -60,7 +74,9 @@ export async function install(platform, engine, version) {
     await io.mv(path.join(parentDir, base), rubyPrefix)
   }
 
-  return rubyPrefix
+  if (common.shouldUseToolCache(engine, version)) {
+    common.createToolCacheCompleteFile(rubyPrefix)
+  }
 }
 
 async function setupMingw(version) {
@@ -120,7 +136,7 @@ export function addVCVARSEnv() {
   let newSet = cp.execSync(cmd).toString().trim().split(/\r?\n/)
   newSet = newSet.filter(line => line.match(/\S=\S/))
   newSet.forEach(s => {
-    let [k,v] = s.split('=', 2)
+    let [k,v] = common.partition(s, '=')
     newEnv.set(k,v)
   })