Only set $BUNDLER_VERSION when needed (Bundler 1, Ruby >= 2.7)

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

.github/workflows/test.yml

@@ -15,21 +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: ubuntu-18.04, ruby: rubinius }
         - { 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 }}
@@ -101,7 +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

@@ -14,21 +14,23 @@ 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 |
-| Rubinius | 4.14 |
 
 `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.
 
+Preview and RC versions of Ruby might be available too on Ubuntu and macOS (not on Windows).
+However, it is recommended to test against `ruby-head` rather than previews,
+as it provides more useful feedback for the Ruby core team and for upcoming changes.
+
 Only versions published by [RubyInstaller](https://rubyinstaller.org/downloads/archives/) are available on Windows.
 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
 
@@ -37,11 +39,9 @@ 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` |
 
-Rubinius is only available on `ubuntu-18.04`.
-
 The prebuilt releases are generated by [ruby-builder](https://github.com/ruby/ruby-builder)
 and on Windows by [RubyInstaller2](https://github.com/oneclick/rubyinstaller2).
 `mingw` and `mswin` builds are generated by [ruby-loco](https://github.com/MSP-Greg/ruby-loco).
@@ -67,7 +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
 ```
 
@@ -86,14 +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
 ```
 
@@ -139,38 +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.
@@ -201,9 +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 +36,29 @@ export function isHeadVersion(rubyVersion) {
   return rubyVersion === 'head' || rubyVersion === 'debug' || rubyVersion === 'mingw' || rubyVersion === 'mswin'
 }
 
+export function isStableVersion(rubyVersion) {
+  return /^\d+(\.\d+)*$/.test(rubyVersion)
+}
+
+export function isBundler2Default(engine, rubyVersion) {
+  if (engine === 'ruby') {
+    return isHeadVersion(rubyVersion) || floatVersion(rubyVersion) >= 2.7
+  } else if (engine === 'truffleruby') {
+    return isHeadVersion(rubyVersion)
+  } else {
+    return false
+  }
+}
+
+export function floatVersion(rubyVersion) {
+  const match = rubyVersion.match(/^\d+\.\d+/)
+  if (match) {
+    return parseFloat(match[0])
+  } else {
+    return 0.0
+  }
+}
+
 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')
@@ -36,34 +67,67 @@ 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-${findUbuntuVersion()}`
+  let match = imageOS.match(/^ubuntu(\d+)/) // e.g. ubuntu18
-  } else if (platform === 'darwin') {
+  if (match) {
-    return 'macos-latest'
+    return `ubuntu-${match[1]}.04`
-  } else if (platform === 'win32') {
+  }
-    return 'windows-latest'
+
+  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 shouldUseToolCache(engine, version) {
+  return engine === 'ruby' && !isHeadVersion(version)
+}
+
+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 ${platform}`)
+    throw new Error('Unknown platform')
   }
 }
 
-function findUbuntuVersion() {
+export function getToolCacheRubyPrefix(platform, version) {
-  const lsb_release = fs.readFileSync('/etc/lsb-release', 'utf8')
+  const toolCache = getPlatformToolCache(platform)
-  const match = lsb_release.match(/^DISTRIB_RELEASE=(\d+\.\d+)$/m)
+  return path.join(toolCache, 'Ruby', version, 'x64')
-  if (match) {
+}
-    return match[1]
+
-  } else {
+export function createToolCacheCompleteFile(toolCacheRubyPrefix) {
-    throw new Error('Could not find Ubuntu version')
+  const completeFile = `${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

@@ -27682,6 +27682,7 @@ const path = __webpack_require__(622)
 const cp = __webpack_require__(129)
 const core = __webpack_require__(186)
 const exec = __webpack_require__(514)
+const io = __webpack_require__(436)
 const tc = __webpack_require__(188)
 const common = __webpack_require__(390)
 const rubyInstallerVersions = __webpack_require__(223).versions
@@ -27711,21 +27712,47 @@ async function install(platform, engine, version) {
   }
   const base = url.slice(url.lastIndexOf('/') + 1, url.length - '.7z'.length)
 
-  const rubyPrefix = `${drive}:\\${base}`
+  let rubyPrefix, inToolCache
+  if (common.shouldUseToolCache(engine, version)) {
+    inToolCache = tc.find('Ruby', version)
+    if (inToolCache) {
+      rubyPrefix = inToolCache
+    } else {
+      rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
+    }
+  } else {
+    rubyPrefix = `${drive}:\\${base}`
+  }
 
   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)
   })
 
   await common.measure('Extracting Ruby', async () =>
-    exec.exec('7z', ['x', downloadPath, `-xr!${base}\\share\\doc`, `-o${drive}:\\`], { silent: true }))
+    exec.exec('7z', ['x', downloadPath, `-xr!${base}\\share\\doc`, `-o${parentDir}`], { silent: true }))
 
-  return rubyPrefix
+  if (base !== path.basename(rubyPrefix)) {
+    await io.mv(path.join(parentDir, base), rubyPrefix)
+  }
+
+  if (common.shouldUseToolCache(engine, version)) {
+    common.createToolCacheCompleteFile(rubyPrefix)
+  }
 }
 
 async function setupMingw(version) {
@@ -27785,7 +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)
   })
 
@@ -32083,10 +32110,17 @@ 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__, "isBundler2Default", function() { return isBundler2Default; });
+/* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "floatVersion", function() { return floatVersion; });
 /* 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__, "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)
@@ -32102,6 +32136,14 @@ 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()
@@ -32119,6 +32161,29 @@ function isHeadVersion(rubyVersion) {
   return rubyVersion === 'head' || rubyVersion === 'debug' || rubyVersion === 'mingw' || rubyVersion === 'mswin'
 }
 
+function isStableVersion(rubyVersion) {
+  return /^\d+(\.\d+)*$/.test(rubyVersion)
+}
+
+function isBundler2Default(engine, rubyVersion) {
+  if (engine === 'ruby') {
+    return isHeadVersion(rubyVersion) || floatVersion(rubyVersion) >= 2.7
+  } else if (engine === 'truffleruby') {
+    return isHeadVersion(rubyVersion)
+  } else {
+    return false
+  }
+}
+
+function floatVersion(rubyVersion) {
+  const match = rubyVersion.match(/^\d+\.\d+/)
+  if (match) {
+    return parseFloat(match[0])
+  } else {
+    return 0.0
+  }
+}
+
 async function hashFile(file) {
   // See https://github.com/actions/runner/blob/master/src/Misc/expressionFunc/hashFiles/src/hashFiles.ts
   const hash = crypto.createHash('sha256')
@@ -32127,34 +32192,67 @@ 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-${findUbuntuVersion()}`
+  let match = imageOS.match(/^ubuntu(\d+)/) // e.g. ubuntu18
-  } else if (platform === 'darwin') {
+  if (match) {
-    return 'macos-latest'
+    return `ubuntu-${match[1]}.04`
-  } else if (platform === 'win32') {
+  }
-    return 'windows-latest'
+
+  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 shouldUseToolCache(engine, version) {
+  return engine === 'ruby' && !isHeadVersion(version)
+}
+
+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 ${platform}`)
+    throw new Error('Unknown platform')
   }
 }
 
-function findUbuntuVersion() {
+function getToolCacheRubyPrefix(platform, version) {
-  const lsb_release = fs.readFileSync('/etc/lsb-release', 'utf8')
+  const toolCache = getPlatformToolCache(platform)
-  const match = lsb_release.match(/^DISTRIB_RELEASE=(\d+\.\d+)$/m)
+  return path.join(toolCache, 'Ruby', version, 'x64')
-  if (match) {
+}
-    return match[1]
+
-  } else {
+function createToolCacheCompleteFile(toolCacheRubyPrefix) {
-    throw new Error('Could not find Ubuntu version')
+  const completeFile = `${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, '\\ ')
 }
@@ -44485,6 +44583,7 @@ 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-preview2",
       "head", "debug",
     ],
     "jruby": [
@@ -44494,17 +44593,11 @@ 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"
     ]
   }
 
-  if (platform === 'ubuntu-18.04') {
-    versions['rubinius'] = [
-      "4.14"
-    ]
-  }
-
   return versions
 }
 
@@ -51161,7 +51254,7 @@ async function setupRuby(options = {}) {
   const [engine, parsedVersion] = parseRubyEngineAndVersion(inputs['ruby-version'])
 
   let installer
-  if (platform === 'windows-latest' && engine !== 'jruby') {
+  if (platform.startsWith('windows-') && engine === 'ruby') {
     installer = __webpack_require__(216)
   } else {
     installer = __webpack_require__(974)
@@ -51185,37 +51278,27 @@ 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]
@@ -51238,7 +51321,7 @@ 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`)
   }
 
@@ -51248,9 +51331,9 @@ function parseRubyEngineAndVersion(rubyVersion) {
     version = rubyVersion
   } else if (!rubyVersion.includes('-')) { // myruby -> myruby-stableVersion
     engine = rubyVersion
-    version = '' // Let the logic below find the version
+    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]
@@ -51264,7 +51347,13 @@ 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 {
@@ -51299,7 +51388,7 @@ 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()))
@@ -51317,7 +51406,7 @@ function readBundledWithFromGemfileLock(lockFile) {
 }
 
 async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefix, engine, rubyVersion) {
-  var bundlerVersion = bundlerVersionInput
+  let bundlerVersion = bundlerVersionInput
 
   if (bundlerVersion === 'default' || bundlerVersion === 'Gemfile.lock') {
     bundlerVersion = readBundledWithFromGemfileLock(lockFile)
@@ -51337,53 +51426,62 @@ 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 (common.isHeadVersion(rubyVersion) && common.isBundler2Default(engine, 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 if (engine === 'rubinius') {
-    console.log(`Rubinius only supports the version of Bundler shipped with it`)
   } 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
   }
 
+  let envOptions = {}
+  if (bundlerVersion.startsWith('1') && common.isBundler2Default(engine, rubyVersion)) {
+    // If Bundler 1 is specified on Rubies which ship with Bundler 2,
+    // we need to specify which Bundler version to use explicitly until the lockfile exists.
+    console.log(`Setting BUNDLER_VERSION=${bundlerVersion} for "bundle config|lock" commands below to ensure Bundler 1 is used`)
+    envOptions = { env: { ...process.env, BUNDLER_VERSION: bundlerVersion } }
+  }
+
   // config
   const path = 'vendor/bundle'
 
-  if (lockFile !== null) {
+  await exec.exec('bundle', ['config', '--local', 'path', path], envOptions)
-    await exec.exec('bundle', ['config', '--local', 'deployment', 'true'])
+
+  if (fs.existsSync(lockFile)) {
+    await exec.exec('bundle', ['config', '--local', 'deployment', 'true'], envOptions)
+  } 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'], envOptions)
   }
-  await exec.exec('bundle', ['config', '--local', 'path', path])
 
   // cache key
   const paths = [path]
-  const baseKey = await computeBaseKey(platform, engine, version)
+  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}-${await common.hashFile(lockFile)}`
-    // If only Gemfile.lock we can reuse some of the cache (but it will keep old gem versions in the cache)
-    restoreKeys = [`${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
@@ -51402,14 +51500,14 @@ 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')
@@ -51429,8 +51527,9 @@ async function bundleInstall(gemfile, lockFile, platform, engine, version) {
   return true
 }
 
-async function computeBaseKey(platform, engine, version) {
+async function computeBaseKey(platform, engine, version, lockFile) {
-  let baseKey = `setup-ruby-bundle-install-${platform}-${engine}-${version}`
+  let key = `setup-ruby-bundler-cache-v2-${platform}-${engine}-${version}`
+
   if (engine !== 'jruby' && common.isHeadVersion(version)) {
     let revision = '';
     await exec.exec('ruby', ['-e', 'print RUBY_REVISION'], {
@@ -51441,9 +51540,11 @@ async function computeBaseKey(platform, engine, version) {
         }
       }
     });
-    baseKey += `-revision-${revision}`
+    key += `-revision-${revision}`
   }
-  return baseKey
+
+  key += `-${lockFile}`
+  return key
 }
 
 if (__filename.endsWith('index.js')) { run() }
@@ -52860,14 +52961,13 @@ __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)
 const common = __webpack_require__(390)
 const rubyBuilderVersions = __webpack_require__(694)
 
-const builderReleaseTag = 'enable-shared'
+const builderReleaseTag = 'toolcache'
 const releasesURL = 'https://github.com/ruby/ruby-builder/releases'
 
 const windows = common.windows
@@ -52877,23 +52977,35 @@ 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) {
-  const rubiesDir = windows ? `${common.drive}:` : path.join(os.homedir(), '.rubies')
+      rubyPrefix = inToolCache
-
+    } else {
-  const rubyPrefix = path.join(rubiesDir, `${engine}-${version}`)
+      rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
-
+    }
-  // Set the PATH now, so the MSYS2 'tar' is in Path on Windows
+  } else if (windows) {
-  if (engine === 'rubinius') {
+    rubyPrefix = path.join(`${common.drive}:`, `${engine}-${version}`)
-    core.warning('Rubinius builds will no longer be provided, see https://github.com/ruby/setup-ruby/issues/101')
-    common.setupPath([path.join(rubyPrefix, 'bin'), path.join(rubyPrefix, 'gems', 'bin')])
   } else {
-    common.setupPath([path.join(rubyPrefix, 'bin')])
+    rubyPrefix = path.join(os.homedir(), '.rubies', `${engine}-${version}`)
   }
 
-  await io.mkdirP(rubiesDir)
+  // 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)
 
   const downloadPath = await common.measure('Downloading Ruby', async () => {
     const url = getDownloadURL(platform, engine, version)
@@ -52904,20 +53016,29 @@ 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(rubiesDir), '-f', common.win2nix(downloadPath) ])
+      await exec.exec('tar', ['-xz', '-C', common.win2nix(parentDir), '-f', common.win2nix(downloadPath)])
     } else {
-      await exec.exec('tar', [ '-xz', '-C', rubiesDir, '-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 !== 'jruby') {
+  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`)
   }
 
@@ -126,9 +116,9 @@ function parseRubyEngineAndVersion(rubyVersion) {
     version = rubyVersion
   } else if (!rubyVersion.includes('-')) { // myruby -> myruby-stableVersion
     engine = rubyVersion
-    version = '' // Let the logic below find the version
+    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()))
@@ -195,7 +191,7 @@ function readBundledWithFromGemfileLock(lockFile) {
 }
 
 async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefix, engine, rubyVersion) {
-  var bundlerVersion = bundlerVersionInput
+  let bundlerVersion = bundlerVersionInput
 
   if (bundlerVersion === 'default' || bundlerVersion === 'Gemfile.lock') {
     bundlerVersion = readBundledWithFromGemfileLock(lockFile)
@@ -215,53 +211,62 @@ 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 (common.isHeadVersion(rubyVersion) && common.isBundler2Default(engine, 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 if (engine === 'rubinius') {
-    console.log(`Rubinius only supports the version of Bundler shipped with it`)
   } 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
   }
 
+  let envOptions = {}
+  if (bundlerVersion.startsWith('1') && common.isBundler2Default(engine, rubyVersion)) {
+    // If Bundler 1 is specified on Rubies which ship with Bundler 2,
+    // we need to specify which Bundler version to use explicitly until the lockfile exists.
+    console.log(`Setting BUNDLER_VERSION=${bundlerVersion} for "bundle config|lock" commands below to ensure Bundler 1 is used`)
+    envOptions = { env: { ...process.env, BUNDLER_VERSION: bundlerVersion } }
+  }
+
   // config
   const path = 'vendor/bundle'
 
-  if (lockFile !== null) {
+  await exec.exec('bundle', ['config', '--local', 'path', path], envOptions)
-    await exec.exec('bundle', ['config', '--local', 'deployment', 'true'])
+
+  if (fs.existsSync(lockFile)) {
+    await exec.exec('bundle', ['config', '--local', 'deployment', 'true'], envOptions)
+  } 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'], envOptions)
   }
-  await exec.exec('bundle', ['config', '--local', 'path', path])
 
   // cache key
   const paths = [path]
-  const baseKey = await computeBaseKey(platform, engine, version)
+  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}-${await common.hashFile(lockFile)}`
-    // If only Gemfile.lock we can reuse some of the cache (but it will keep old gem versions in the cache)
-    restoreKeys = [`${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
@@ -280,14 +285,14 @@ 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')
@@ -307,8 +312,9 @@ async function bundleInstall(gemfile, lockFile, platform, engine, version) {
   return true
 }
 
-async function computeBaseKey(platform, engine, version) {
+async function computeBaseKey(platform, engine, version, lockFile) {
-  let baseKey = `setup-ruby-bundle-install-${platform}-${engine}-${version}`
+  let key = `setup-ruby-bundler-cache-v2-${platform}-${engine}-${version}`
+
   if (engine !== 'jruby' && common.isHeadVersion(version)) {
     let revision = '';
     await exec.exec('ruby', ['-e', 'print RUBY_REVISION'], {
@@ -319,9 +325,11 @@ async function computeBaseKey(platform, engine, version) {
         }
       }
     });
-    baseKey += `-revision-${revision}`
+    key += `-revision-${revision}`
   }
-  return baseKey
+
+  key += `-${lockFile}`
+  return key
 }
 
 if (__filename.endsWith('index.js')) { run() }

ruby-builder-versions.js

@@ -8,6 +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-preview2",
       "head", "debug",
     ],
     "jruby": [
@@ -17,16 +18,10 @@ 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"
     ]
   }
 
-  if (platform === 'ubuntu-18.04') {
-    versions['rubinius'] = [
-      "4.14"
-    ]
-  }
-
   return versions
 }

ruby-builder.js

@@ -1,13 +1,12 @@
 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')
 const common = require('./common')
 const rubyBuilderVersions = require('./ruby-builder-versions')
 
-const builderReleaseTag = 'enable-shared'
+const builderReleaseTag = 'toolcache'
 const releasesURL = 'https://github.com/ruby/ruby-builder/releases'
 
 const windows = common.windows
@@ -17,23 +16,35 @@ 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) {
-  const rubiesDir = windows ? `${common.drive}:` : path.join(os.homedir(), '.rubies')
+      rubyPrefix = inToolCache
-
+    } else {
-  const rubyPrefix = path.join(rubiesDir, `${engine}-${version}`)
+      rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
-
+    }
-  // Set the PATH now, so the MSYS2 'tar' is in Path on Windows
+  } else if (windows) {
-  if (engine === 'rubinius') {
+    rubyPrefix = path.join(`${common.drive}:`, `${engine}-${version}`)
-    core.warning('Rubinius builds will no longer be provided, see https://github.com/ruby/setup-ruby/issues/101')
-    common.setupPath([path.join(rubyPrefix, 'bin'), path.join(rubyPrefix, 'gems', 'bin')])
   } else {
-    common.setupPath([path.join(rubyPrefix, 'bin')])
+    rubyPrefix = path.join(os.homedir(), '.rubies', `${engine}-${version}`)
   }
 
-  await io.mkdirP(rubiesDir)
+  // 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)
 
   const downloadPath = await common.measure('Downloading Ruby', async () => {
     const url = getDownloadURL(platform, engine, version)
@@ -44,20 +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(rubiesDir), '-f', common.win2nix(downloadPath) ])
+      await exec.exec('tar', ['-xz', '-C', common.win2nix(parentDir), '-f', common.win2nix(downloadPath)])
     } else {
-      await exec.exec('tar', [ '-xz', '-C', rubiesDir, '-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

@@ -6,6 +6,7 @@ const path = require('path')
 const cp = require('child_process')
 const core = require('@actions/core')
 const exec = require('@actions/exec')
+const io = require('@actions/io')
 const tc = require('@actions/tool-cache')
 const common = require('./common')
 const rubyInstallerVersions = require('./windows-versions').versions
@@ -35,21 +36,47 @@ export async function install(platform, engine, version) {
   }
   const base = url.slice(url.lastIndexOf('/') + 1, url.length - '.7z'.length)
 
-  const rubyPrefix = `${drive}:\\${base}`
+  let rubyPrefix, inToolCache
+  if (common.shouldUseToolCache(engine, version)) {
+    inToolCache = tc.find('Ruby', version)
+    if (inToolCache) {
+      rubyPrefix = inToolCache
+    } else {
+      rubyPrefix = common.getToolCacheRubyPrefix(platform, version)
+    }
+  } else {
+    rubyPrefix = `${drive}:\\${base}`
+  }
 
   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)
   })
 
   await common.measure('Extracting Ruby', async () =>
-    exec.exec('7z', ['x', downloadPath, `-xr!${base}\\share\\doc`, `-o${drive}:\\`], { silent: true }))
+    exec.exec('7z', ['x', downloadPath, `-xr!${base}\\share\\doc`, `-o${parentDir}`], { silent: true }))
 
-  return rubyPrefix
+  if (base !== path.basename(rubyPrefix)) {
+    await io.mv(path.join(parentDir, base), rubyPrefix)
+  }
+
+  if (common.shouldUseToolCache(engine, version)) {
+    common.createToolCacheCompleteFile(rubyPrefix)
+  }
 }
 
 async function setupMingw(version) {
@@ -109,7 +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)
   })