Document the consequences of using a specific version or commit sha

* That was rather confusing.

.github/workflows/test.yml

@@ -3,7 +3,6 @@ on:
   pull_request:
   push:
     branches-ignore:
-    - master
     - v1
     tags-ignore:
     - '*'
@@ -15,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu, macos, windows ]
-        # Use various version syntaxes here for testing
+        # Use various version syntax here for testing
         ruby: [ 2.2, 2.3, 2.4, 2.5, 2.6.6, 2.7, ruby-head, jruby-9.1, jruby, jruby-head, truffleruby, truffleruby-head ]
         include:
         - { os: ubuntu, ruby: rubinius }
@@ -29,15 +28,17 @@ jobs:
     runs-on: ${{ matrix.os }}-latest
     steps:
     - uses: actions/checkout@v2
+
     - uses: ./
       with:
         ruby-version: ${{ matrix.ruby }}
     - run: ruby -v
+
     - name: build compiler
       run: |
         ruby -e "puts 'build compiler: ' + RbConfig::CONFIG.fetch('CC_VERSION_MESSAGE', 'unknown').lines.first"
     - name: gcc and ridk version (mingw)
-      if: startsWith(matrix.os, 'windows')
+      if: matrix.os == 'windows'
       run: |
         $abi, $plat = $(ruby -e "STDOUT.write RbConfig::CONFIG['ruby_version'] + ' ' + RUBY_PLATFORM").split(' ')
         if ($plat.Contains('mingw')) {
@@ -48,22 +49,25 @@ jobs:
             echo 'ridk is unavailable'
           }
         }
+
     - name: Subprocess test
       run: ruby test_subprocess.rb
     - name: OpenSSL version
       run: ruby -ropenssl -e 'puts OpenSSL::OPENSSL_LIBRARY_VERSION'
     - name: OpenSSL test
       run: ruby -ropen-uri -e 'puts open(%{https://rubygems.org/}) { |f| f.read(1024) }'
+
     - name: C extension test
       run: gem install json:2.2.0 --no-document
     - run: bundle --version
     - run: bundle install
     - run: bundle exec rake --version
+
     - name: which ruby, rake
-      if: startsWith(matrix.os, 'windows') == false
+      if: matrix.os != 'windows'
       run: which -a ruby rake
     - name: where ruby, rake
-      if: startsWith(matrix.os, 'windows')
+      if: matrix.os == 'windows'
       run: |
         $ErrorActionPreference = 'Continue'
         $where = 'ruby', 'rake'
@@ -74,6 +78,7 @@ jobs:
           echo ''
         }
 
+
   lint:
     runs-on: ubuntu-latest
     steps:

README.md

@@ -146,15 +146,22 @@ It is recommended to first get your build working on Ubuntu and macOS before try
 * For Ruby < 2.4, the DevKit MSYS tools are installed and prepended to the `Path`.
 * JRuby on Windows has a known bug that `bundle exec rake` [fails](https://github.com/ruby/setup-ruby/issues/18).
 
-## Limitations
-
-* This action currently only works with GitHub-hosted runners, not private runners.
-
 ## Versioning
 
+It is highly recommended to use `ruby/setup-ruby@v1` for the version of this action.
+This will provide the best experience by automatically getting bug fixes, new Ruby versions and new features.
+
+If you instead choose a specific version (v1.2.3) or a commit sha, there will be no automatic bug fixes and
+it will be your responsibility to update every time the action no longer works.
+Make sure to always use the latest release before reporting an issue on GitHub.
+
 This action follows semantic versioning with a moving `v1` branch.
 This follows the [recommendations](https://github.com/actions/toolkit/blob/master/docs/action-versioning.md) of GitHub Actions.
 
+## Limitations
+
+* This action currently only works with GitHub-hosted runners, not private runners.
+
 ## History
 
 This action used to be at `eregon/use-ruby-action` and was moved to the `ruby` organization.

dist/index.js

@@ -984,8 +984,10 @@ async function run() {
 
     setupPath(ruby, newPathEntries)
 
-    await common.measure('Installing Bundler', async () =>
+    if (core.getInput('bundler') !== 'none') {
-      installBundler(platform, rubyPrefix, engine, version))
+      await common.measure('Installing Bundler', async () =>
+        installBundler(platform, rubyPrefix, engine, version))
+    }
 
     core.setOutput('ruby-prefix', rubyPrefix)
   } catch (error) {
@@ -1093,9 +1095,6 @@ function readBundledWithFromGemfileLock() {
 
 async function installBundler(platform, rubyPrefix, engine, rubyVersion) {
   var bundlerVersion = core.getInput('bundler')
-  if (bundlerVersion === 'none') {
-    return
-  }
 
   if (bundlerVersion === 'default' || bundlerVersion === 'Gemfile.lock') {
     bundlerVersion = readBundledWithFromGemfileLock()

index.js

@@ -26,8 +26,10 @@ export async function run() {
 
     setupPath(ruby, newPathEntries)
 
-    await common.measure('Installing Bundler', async () =>
+    if (core.getInput('bundler') !== 'none') {
-      installBundler(platform, rubyPrefix, engine, version))
+      await common.measure('Installing Bundler', async () =>
+        installBundler(platform, rubyPrefix, engine, version))
+    }
 
     core.setOutput('ruby-prefix', rubyPrefix)
   } catch (error) {
@@ -135,9 +137,6 @@ function readBundledWithFromGemfileLock() {
 
 async function installBundler(platform, rubyPrefix, engine, rubyVersion) {
   var bundlerVersion = core.getInput('bundler')
-  if (bundlerVersion === 'none') {
-    return
-  }
 
   if (bundlerVersion === 'default' || bundlerVersion === 'Gemfile.lock') {
     bundlerVersion = readBundledWithFromGemfileLock()