Resolve latest JReleaser release

README.adoc

@@ -89,7 +89,7 @@ Following inputs can be used as `step.with` keys
 [%header,cols="<2,<,<2,<3",width="100%"]
 |===
 | Name              | Type   | Default                 | Description
-| version           | String | early-access            | The JReleaser version to use. +
+| version           | String | latest                  | The JReleaser version to use. +
 Should match any of the link:https://github.com/jreleaser/jreleaser/releases[published releases].
 | arguments         | String | full-release            | The JReleaser command to run.
 | working-directory | String | ${{ github.workspace }} | The directory to change into. +

action.yml

@@ -10,7 +10,7 @@ inputs:
 
   version:
     description: 'The version of JReleaser to download and execute.'
-    default: 'early-access'
+    default: 'latest'
     required: true
 
   arguments:

get_jreleaser.java

@@ -7,14 +7,47 @@ import java.nio.file.StandardCopyOption;
 
 class get_jreleaser {
     public static void main(String... args) throws Exception {
-    if (args.length != 1) {
+        // default version
-      System.err.println("Usage: java get_jreleaser.java VERSION");
+        var version = "latest";
+
+        if (args.length > 1) {
+            System.err.println("Usage: java get_jreleaser.java [VERSION]");
             System.exit(1);
         }
 
-    // TODO: handle version = 'latest'
+        // grab the version if specified
+        if (args.length == 1) {
+            version = args[0];
+        }
 
-    var version = args[0];
+        // check
+        if (null == version || version.isEmpty()) {
+            System.out.printf("❌ Version '%s' is invalid%n", version);
+            System.exit(1);
+        }
+
+        // resolve latest to a tagged release
+        if ("latest".equalsIgnoreCase(version)) {
+            var url = "https://jreleaser.org/releases/latest/download/VERSION";
+            var file = Path.of("VERSION");
+
+            try (var stream = new URL(url).openStream()) {
+                System.out.printf("✅ Located version marker%n");
+                Files.copy(stream, file, StandardCopyOption.REPLACE_EXISTING);
+                version = new String(Files.readAllBytes(file)).trim();
+                System.out.printf("✅ JReleaser latest resolves to %s%n", version);
+            } catch (FileNotFoundException e) {
+                System.out.printf("❌ JReleaser %s not found%n", version);
+                e.printStackTrace();
+                System.exit(1);
+            } catch (IOException e) {
+                System.out.printf("☠️  JReleaser %s could not be downloaded/copied%n", version);
+                e.printStackTrace();
+                System.exit(1);
+            }
+        }
+
+        // setup the actual download
         var url = "https://github.com/jreleaser/jreleaser/releases/download/" + version + "/jreleaser-tool-provider-" + version + ".jar";
         var file = Path.of("jreleaser-cli.jar");