Use implicit defaults for most inputs so the GitHub Actions UI shows only the set options

* Fixes https://github.com/ruby/setup-ruby/issues/327

.github/workflows/test.yml

@@ -113,7 +113,7 @@ jobs:
       run: gem install sassc
 
   testLatestRubygemsVersion:
-    name: "Test rubygems input set to latest upgrades the default RubyGems version"
+    name: "Test rubygems: latest upgrades the default RubyGems version"
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
@@ -124,7 +124,7 @@ jobs:
     - run: ruby -e "exit(Gem.rubygems_version > Gem::Version.new('3.0.3'))"
 
   testFixedRubygemsVersionUpgrades:
-    name: "Test rubygems input set to a fixed version upgrades RubyGems to that version if the default is older"
+    name: "Test rubygems: version upgrades RubyGems to that version if the default is older"
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
@@ -135,7 +135,7 @@ jobs:
     - run: gem --version | grep -F "3.2.3"
 
   testFixedRubygemsVersionNoop:
-    name: "Test rubygems input set to a fixed version noops if the default is newer"
+    name: "Test rubygems: version noops if the default is newer"
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
@@ -145,6 +145,29 @@ jobs:
         rubygems: 3.2.3
     - run: gem --version | grep -F "3.3.3"
 
+  testUseBundlerFromRubyGemsUpdate:
+    name: "Test rubygems: version uses the Bundler installed by the rubygems update"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ./
+        with:
+          ruby-version: 2.2
+          rubygems: 2.7.11
+      - run: gem --version | grep -F "2.7.11"
+      - run: bundle --version | grep -F "1.16.6"
+
+  testFixedBundlerVersionForOldRuby:
+    name: "Test bundler: 1.x for old Ruby"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ./
+        with:
+          ruby-version: 2.2
+          bundler: 1.16.6
+      - run: bundle --version | grep -F "1.16.6" # And not 1.17.x from ~> 1
+
   testMajorBundlerVersion:
     name: "Test with a major Bundler version"
     runs-on: ubuntu-latest

action.yml

@@ -7,36 +7,27 @@ branding:
 inputs:
   ruby-version:
     description: 'Engine and version to use, see the syntax in the README. Reads from .ruby-version or .tool-versions if unset.'
-    required: false
     default: 'default'
   rubygems:
     description: |
-      The version of RubyGems to use. Either 'default', 'latest', or a version number (e.g., 3.3.5).
+      The version of RubyGems to use. Either 'default' (the default), 'latest', or a version number (e.g., 3.3.5).
       For 'default', no action is taken and the version of RubyGems that comes with Ruby by default is used.
       For 'latest', `gem update --system` is run to update to the latest RubyGems version.
       Similarly, if a version number is given, `gem update --system <version>` is run to update to that version of RubyGems, as long as that version is newer than the one provided by default.
-      Defaults to 'default'.
   bundler:
     description: |
       The version of Bundler to install. Either 'none', 'latest', 'Gemfile.lock', or a version number (e.g., 1, 2, 2.1, 2.1.4).
       For 'Gemfile.lock', the version is determined based on the BUNDLED WITH section from the file Gemfile.lock, $BUNDLE_GEMFILE.lock or gems.locked.
-      Defaults to 'Gemfile.lock' if the file exists and 'latest' otherwise.
-    required: false
-    default: 'default'
+      Defaults to 'default', which means 'Gemfile.lock' if the file exists and 'latest' otherwise.
   bundler-cache:
     description: 'Run "bundle install", and cache the result automatically. Either true or false.'
-    required: false
     default: 'false'
   working-directory:
     description: 'The working directory to use for resolving paths for .ruby-version, .tool-versions and Gemfile.lock.'
-    required: false
-    default: '.'
   cache-version:
     description: |
       Arbitrary string that will be added to the cache key of the bundler cache. Set or change it if you need
       to invalidate the cache.
-    required: false
-    default: '0'
 outputs:
   ruby-prefix:
     description: 'The prefix of the installed ruby'

bundler.js

@@ -50,9 +50,14 @@ async function afterLockFile(lockFile, platform, engine, rubyVersion) {
   }
 }
 
-export async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefix, engine, rubyVersion) {
+export async function installBundler(bundlerVersionInput, rubygemsInputSet, lockFile, platform, rubyPrefix, engine, rubyVersion) {
   let bundlerVersion = bundlerVersionInput
 
+  if (rubygemsInputSet && bundlerVersion === 'default') {
+    console.log('Using the Bundler installed by updating RubyGems')
+    return 'unknown'
+  }
+
   if (bundlerVersion === 'default' || bundlerVersion === 'Gemfile.lock') {
     bundlerVersion = readBundledWithFromGemfileLock(lockFile)
 
@@ -73,15 +78,18 @@ export async function installBundler(bundlerVersionInput, lockFile, platform, ru
 
   const floatVersion = common.floatVersion(rubyVersion)
 
-  if (engine === 'ruby' && floatVersion <= 2.2) {
-    console.log('Bundler 2 requires Ruby 2.3+, using Bundler 1 on Ruby <= 2.2')
-    bundlerVersion = '1'
-  } else if (engine === 'ruby' && /^2\.3\.[01]/.test(rubyVersion)) {
-    console.log('Ruby 2.3.0 and 2.3.1 have shipped with an old rubygems that only works with Bundler 1')
-    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'
+  // Use Bundler 1 when we know Bundler 2 does not work
+  if (bundlerVersion.startsWith('2')) {
+    if (engine === 'ruby' && floatVersion <= 2.2) {
+      console.log('Bundler 2 requires Ruby 2.3+, using Bundler 1 on Ruby <= 2.2')
+      bundlerVersion = '1'
+    } else if (engine === 'ruby' && /^2\.3\.[01]/.test(rubyVersion)) {
+      console.log('Ruby 2.3.0 and 2.3.1 have shipped with an old rubygems that only works with Bundler 1')
+      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'
+    }
   }
 
   // Workaround for truffleruby 22.0 + latest Bundler, use shipped Bundler instead: https://github.com/oracle/truffleruby/issues/2586

dist/index.js

@@ -64,9 +64,14 @@ async function afterLockFile(lockFile, platform, engine, rubyVersion) {
   }
 }
 
-async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefix, engine, rubyVersion) {
+async function installBundler(bundlerVersionInput, rubygemsInputSet, lockFile, platform, rubyPrefix, engine, rubyVersion) {
   let bundlerVersion = bundlerVersionInput
 
+  if (rubygemsInputSet && bundlerVersion === 'default') {
+    console.log('Using the Bundler installed by updating RubyGems')
+    return 'unknown'
+  }
+
   if (bundlerVersion === 'default' || bundlerVersion === 'Gemfile.lock') {
     bundlerVersion = readBundledWithFromGemfileLock(lockFile)
 
@@ -87,15 +92,18 @@ async function installBundler(bundlerVersionInput, lockFile, platform, rubyPrefi
 
   const floatVersion = common.floatVersion(rubyVersion)
 
-  if (engine === 'ruby' && floatVersion <= 2.2) {
-    console.log('Bundler 2 requires Ruby 2.3+, using Bundler 1 on Ruby <= 2.2')
-    bundlerVersion = '1'
-  } else if (engine === 'ruby' && /^2\.3\.[01]/.test(rubyVersion)) {
-    console.log('Ruby 2.3.0 and 2.3.1 have shipped with an old rubygems that only works with Bundler 1')
-    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'
+  // Use Bundler 1 when we know Bundler 2 does not work
+  if (bundlerVersion.startsWith('2')) {
+    if (engine === 'ruby' && floatVersion <= 2.2) {
+      console.log('Bundler 2 requires Ruby 2.3+, using Bundler 1 on Ruby <= 2.2')
+      bundlerVersion = '1'
+    } else if (engine === 'ruby' && /^2\.3\.[01]/.test(rubyVersion)) {
+      console.log('Ruby 2.3.0 and 2.3.1 have shipped with an old rubygems that only works with Bundler 1')
+      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'
+    }
   }
 
   // Workaround for truffleruby 22.0 + latest Bundler, use shipped Bundler instead: https://github.com/oracle/truffleruby/issues/2586
@@ -60829,7 +60837,7 @@ const inputDefaults = {
   'ruby-version': 'default',
   'rubygems': 'default',
   'bundler': 'default',
-  'bundler-cache': 'true',
+  'bundler-cache': 'false',
   'working-directory': '.',
   'cache-version': bundler.DEFAULT_CACHE_VERSION,
 }
@@ -60882,7 +60890,8 @@ async function setupRuby(options = {}) {
   await common.measure('Print Ruby version', async () =>
     await exec.exec('ruby', ['--version']))
 
-  if (inputs['rubygems'] !== 'default') {
+  const rubygemsInputSet = inputs['rubygems'] !== 'default'
+  if (rubygemsInputSet) {
     await common.measure('Updating RubyGems', async () =>
       rubygems.rubygemsUpdate(inputs['rubygems'], rubyPrefix))
   }
@@ -60895,11 +60904,11 @@ async function setupRuby(options = {}) {
   }
 
   const [gemfile, lockFile] = bundler.detectGemfiles()
-  let bundlerVersion = "unknown"
+  let bundlerVersion = 'unknown'
 
   if (inputs['bundler'] !== 'none') {
     bundlerVersion = await common.measure('Installing Bundler', async () =>
-      bundler.installBundler(inputs['bundler'], lockFile, platform, rubyPrefix, engine, version))
+      bundler.installBundler(inputs['bundler'], rubygemsInputSet, lockFile, platform, rubyPrefix, engine, version))
   }
 
   if (inputs['bundler-cache'] === 'true') {

index.js

@@ -13,7 +13,7 @@ const inputDefaults = {
   'ruby-version': 'default',
   'rubygems': 'default',
   'bundler': 'default',
-  'bundler-cache': 'true',
+  'bundler-cache': 'false',
   'working-directory': '.',
   'cache-version': bundler.DEFAULT_CACHE_VERSION,
 }
@@ -66,7 +66,8 @@ export async function setupRuby(options = {}) {
   await common.measure('Print Ruby version', async () =>
     await exec.exec('ruby', ['--version']))
 
-  if (inputs['rubygems'] !== 'default') {
+  const rubygemsInputSet = inputs['rubygems'] !== 'default'
+  if (rubygemsInputSet) {
     await common.measure('Updating RubyGems', async () =>
       rubygems.rubygemsUpdate(inputs['rubygems'], rubyPrefix))
   }
@@ -79,11 +80,11 @@ export async function setupRuby(options = {}) {
   }
 
   const [gemfile, lockFile] = bundler.detectGemfiles()
-  let bundlerVersion = "unknown"
+  let bundlerVersion = 'unknown'
 
   if (inputs['bundler'] !== 'none') {
     bundlerVersion = await common.measure('Installing Bundler', async () =>
-      bundler.installBundler(inputs['bundler'], lockFile, platform, rubyPrefix, engine, version))
+      bundler.installBundler(inputs['bundler'], rubygemsInputSet, lockFile, platform, rubyPrefix, engine, version))
   }
 
   if (inputs['bundler-cache'] === 'true') {