Incorporate reviewer feedback.

src/features/check-for-updates.ts

@@ -14,7 +14,7 @@ export async function checkForUpdates(
   ) {
     const recommendedJDK = javaVersion === '17' ? '17' : '20'
     core.notice(
-      `A new GraalVM release is available! Please consider upgrading to GraalVM for JDK ${recommendedJDK}. Release notes: https://www.graalvm.org/release-notes/JDK_${recommendedJDK}/`
+      `A new GraalVM release is available! Please consider upgrading to GraalVM for JDK ${recommendedJDK}. Instructions: https://github.com/graalvm/setup-graalvm#migrating-from-graalvm-223-or-earlier-to-the-new-graalvm-for-jdk-17-and-later`
     )
     return
   }

src/graalvm.ts

@@ -9,7 +9,7 @@ import {
 import {downloadGraalVMEELegacy} from './gds'
 import {downloadTool} from '@actions/tool-cache'
 import {basename} from 'path'
-import {gt} from 'semver'
+import {gt as semverGt, valid as semverValid} from 'semver'
 
 const GRAALVM_DL_BASE = 'https://download.oracle.com/graalvm'
 const GRAALVM_CE_DL_BASE = `https://github.com/graalvm/${c.GRAALVM_RELEASES_REPO}/releases/download`
@@ -70,7 +70,10 @@ export async function findLatestGraalVMJDKCEJavaVersion(
   const versionNumberStartIndex = `refs/tags/${GRAALVM_JDK_TAG_PREFIX}`.length
   for (const matchingRef of matchingRefs) {
     const currentVersion = matchingRef.ref.substring(versionNumberStartIndex)
-    if (gt(currentVersion, highestVersion)) {
+    if (
+      semverValid(currentVersion) &&
+      semverGt(currentVersion, highestVersion)
+    ) {
       highestVersion = currentVersion
     }
   }

src/main.ts

@@ -1,6 +1,7 @@
 import * as c from './constants'
 import * as core from '@actions/core'
 import * as graalvm from './graalvm'
+import {gte as semverGte, valid as semverValid} from 'semver'
 import {isFeatureAvailable as isCacheAvailable} from '@actions/cache'
 import {join} from 'path'
 import {restore} from './features/cache'
@@ -69,7 +70,10 @@ async function run(): Promise<void> {
     } else {
       switch (graalvmVersion) {
         case c.VERSION_LATEST:
-          if (javaVersion.startsWith('17') || javaVersion.startsWith('20')) {
+          if (
+            javaVersion.startsWith('17') ||
+            (semverValid(javaVersion) && semverGte(javaVersion, '20'))
+          ) {
             core.info(
               `This build is using the new Oracle GraalVM. To select a specific distribution, use the 'distribution' option (see https://github.com/graalvm/setup-graalvm/tree/main#options).`
             )