Ensure an engine-only ruby-version picks the latest stable version and not a preview or RC

README.md

@@ -170,6 +170,7 @@ 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 default tool cache directory (`/opt/hostedtoolcache` on Linux, `/Users/runner/hostedtoolcache` on macOS,

common.js

@@ -28,6 +28,10 @@ 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')

dist/index.js

@@ -32096,6 +32096,7 @@ __webpack_require__.r(__webpack_exports__);
 /* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "drive", function() { return drive; });
 /* 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; });
@@ -32132,6 +32133,10 @@ 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')
@@ -51290,7 +51295,7 @@ 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))
+    const found = latestToFirstVersion.find(v => common.isStableVersion(v) && v.startsWith(parsedVersion))
     if (found) {
       version = found
     } else {

index.js

@@ -132,7 +132,7 @@ 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))
+    const found = latestToFirstVersion.find(v => common.isStableVersion(v) && v.startsWith(parsedVersion))
     if (found) {
       version = found
     } else {