Keep documentation about the version syntax in one place

* Fixes https://github.com/eregon/use-ruby-action/issues/4

.github/workflows/test.yml

@@ -7,7 +7,7 @@ jobs:
       matrix:
         os: [ ubuntu-16.04, ubuntu-18.04, macos-latest, windows-latest ]
         # Use various version syntaxes here for testing
-        ruby: [ 2.3, ruby-2.4, 2.5, ruby-2.6.5, 2.7.0, jruby, truffleruby ]
+        ruby: [ .ruby-version, 2.3, ruby-2.4, 2.5, ruby-2.6.5, 2.7.0, jruby, truffleruby ]
         exclude:
         - os: windows-latest
           ruby: 2.3
@@ -21,8 +21,21 @@ jobs:
     - uses: ./
       with:
         ruby-version: ${{ matrix.ruby }}
-    - run: ruby -v
+    - run: ruby --version
     - run: ridk version
       if: matrix.os == 'windows-latest'
-    - run: ruby -ropen-uri -e 'puts open(%{https://rubygems.org/}) { |f| f.read(2014) }'
-    - run: gem install json --no-document
+    - name: OpenSSL test
+      run: ruby -ropen-uri -e 'puts open(%{https://rubygems.org/}) { |f| f.read(2014) }'
+    - name: C extension test
+      run: gem install json --no-document
+    - name: Check that Bundler is installed
+      run: bundle --version
+    - name: Check that Bundler works
+      run: bundle install
+
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - run: yarn install
+    - run: yarn run lint

.ruby-version

@@ -0,0 +1 @@
+ruby-2.6.5

Gemfile

@@ -0,0 +1,5 @@
+# Used for testing
+source 'https://rubygems.org'
+
+gem "path"
+gem "json"

README.md

@@ -82,6 +82,13 @@ jobs:
 * short version like `2.6`, automatically using the latest release matching that version (`2.6.5`)
 * version only like `2.6.5`, assumes MRI for the engine
 * engine only like `truffleruby`, uses the latest stable release of that implementation
+* `.ruby-version` (also the default value) reads from the project's `.ruby-version` file
+
+### Bundler
+
+Currently, Bundler is guaranteed to be installed for all versions.
+If the Ruby ships with Bundler (Ruby >= 2.6), that version is used.
+Otherwise (Ruby < 2.6), the latest version of Bundler is installed when that Ruby was built.
 
 ## Limitations
 

action.yml

@@ -6,8 +6,8 @@ branding:
   icon: download
 inputs:
   ruby-version:
-    description: 'Engine and version to use, see the syntax in the README'
-    required: true
+    description: 'Engine and version to use, see the syntax in the README. Reads from .ruby-version if unset.'
+    default: '.ruby-version'
 outputs:
   ruby-prefix:
     description: 'The prefix of the installed ruby'

dist/index.js

@@ -1428,6 +1428,11 @@ async function getLatestReleaseTag() {
 }
 
 async function getRubyEngineAndVersion(rubyVersion) {
+  if (rubyVersion === '.ruby-version') { // Read from .ruby-version
+    rubyVersion = fs.readFileSync('.ruby-version', 'utf8').trim()
+    console.log(`Using ${rubyVersion} as input from file .ruby-version`)
+  }
+
   let engine, version
   if (rubyVersion.match(/^\d+/)) { // X.Y.Z => ruby-X.Y.Z
     engine = 'ruby'
@@ -6463,6 +6468,7 @@ __webpack_require__.r(__webpack_exports__);
 // Most of this logic is from
 // https://github.com/MSP-Greg/actions-ruby/blob/master/lib/main.js
 
+const fs = __webpack_require__(747)
 const core = __webpack_require__(470)
 const exec = __webpack_require__(986)
 const tc = __webpack_require__(533)
@@ -6488,6 +6494,10 @@ async function downloadExtractAndSetPATH(ruby) {
   const newPath = setupPath(msys2, rubyPrefix)
   core.exportVariable('PATH', newPath)
 
+  if (!fs.existsSync(`${rubyPrefix}\\bin\\bundle.cmd`)) {
+    await exec.exec(`${rubyPrefix}\\bin\\gem install bundler --no-document`)
+  }
+
   return rubyPrefix
 }
 

index.js

@@ -47,6 +47,11 @@ async function getLatestReleaseTag() {
 }
 
 async function getRubyEngineAndVersion(rubyVersion) {
+  if (rubyVersion === '.ruby-version') { // Read from .ruby-version
+    rubyVersion = fs.readFileSync('.ruby-version', 'utf8').trim()
+    console.log(`Using ${rubyVersion} as input from file .ruby-version`)
+  }
+
   let engine, version
   if (rubyVersion.match(/^\d+/)) { // X.Y.Z => ruby-X.Y.Z
     engine = 'ruby'

windows.js

@@ -1,6 +1,7 @@
 // Most of this logic is from
 // https://github.com/MSP-Greg/actions-ruby/blob/master/lib/main.js
 
+const fs = require('fs')
 const core = require('@actions/core')
 const exec = require('@actions/exec')
 const tc = require('@actions/tool-cache')
@@ -26,6 +27,10 @@ export async function downloadExtractAndSetPATH(ruby) {
   const newPath = setupPath(msys2, rubyPrefix)
   core.exportVariable('PATH', newPath)
 
+  if (!fs.existsSync(`${rubyPrefix}\\bin\\bundle.cmd`)) {
+    await exec.exec(`${rubyPrefix}\\bin\\gem install bundler --no-document`)
+  }
+
   return rubyPrefix
 }