feat: suppress Maven transfer progress via MAVEN_ARGS by default

Set MAVEN_ARGS to include -ntp (--no-transfer-progress) so Maven invocations
in the job produce cleaner CI logs without download/transfer progress noise.
Add a new optional 'show-download-progress' input (default false); set it to
true to keep the progress output.

The change preserves any existing MAVEN_ARGS value (the flag is appended,
not overwritten) and is idempotent (it won't add the flag twice if -ntp or
--no-transfer-progress is already present). Applies on all platforms; honored
by Maven 3.9.0+ and the Maven Wrapper, and is a no-op for non-Maven builds.

- action.yml: add show-download-progress input
- src/constants.ts: add input + MAVEN_ARGS constants
- src/maven-args.ts: new configureMavenArgs()
- src/setup-java.ts: invoke configureMavenArgs() during setup
- __tests__/maven-args.test.ts: unit tests
- docs/advanced-usage.md: document the behavior and input
- dist: rebuild bundled action

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/constants.ts

@@ -28,5 +28,10 @@ export const MVN_SETTINGS_FILE = 'settings.xml';
 export const MVN_TOOLCHAINS_FILE = 'toolchains.xml';
 export const INPUT_MVN_TOOLCHAIN_ID = 'mvn-toolchain-id';
 export const INPUT_MVN_TOOLCHAIN_VENDOR = 'mvn-toolchain-vendor';
+export const INPUT_SHOW_DOWNLOAD_PROGRESS = 'show-download-progress';
+
+export const MAVEN_ARGS_ENV = 'MAVEN_ARGS';
+export const MAVEN_NO_TRANSFER_PROGRESS_FLAG = '-ntp';
+export const MAVEN_NO_TRANSFER_PROGRESS_LONG_FLAG = '--no-transfer-progress';
 
 export const DISTRIBUTIONS_ONLY_MAJOR_VERSION = ['corretto'];

src/maven-args.ts

@@ -0,0 +1,69 @@
+import * as core from '@actions/core';
+import {getBooleanInput} from './util';
+import {
+  INPUT_SHOW_DOWNLOAD_PROGRESS,
+  MAVEN_ARGS_ENV,
+  MAVEN_NO_TRANSFER_PROGRESS_FLAG,
+  MAVEN_NO_TRANSFER_PROGRESS_LONG_FLAG
+} from './constants';
+
+/**
+ * Configures the MAVEN_ARGS environment variable so that Maven suppresses
+ * artifact transfer/download progress output by default, producing cleaner
+ * CI logs.
+ *
+ * Behavior:
+ * - When `show-download-progress` is `false` (the default), `-ntp`
+ *   (`--no-transfer-progress`) is appended to any existing MAVEN_ARGS value.
+ * - When `show-download-progress` is `true`, MAVEN_ARGS is left untouched so
+ *   the user's own configuration (and Maven's default progress output) is
+ *   preserved.
+ *
+ * The change is idempotent: if MAVEN_ARGS already disables transfer progress
+ * (via `-ntp` or `--no-transfer-progress`) nothing is added. Any pre-existing
+ * MAVEN_ARGS value is preserved.
+ *
+ * MAVEN_ARGS is honored by Maven 3.9.0+ and the Maven Wrapper; older Maven
+ * versions ignore it, so this is a no-op there. It has no effect on non-Maven
+ * builds such as Gradle or sbt.
+ */
+export function configureMavenArgs(): void {
+  const showDownloadProgress = getBooleanInput(
+    INPUT_SHOW_DOWNLOAD_PROGRESS,
+    false
+  );
+
+  if (showDownloadProgress) {
+    core.debug(
+      `${INPUT_SHOW_DOWNLOAD_PROGRESS} is true; leaving ${MAVEN_ARGS_ENV} unchanged`
+    );
+    return;
+  }
+
+  const existingArgs = (process.env[MAVEN_ARGS_ENV] ?? '').trim();
+
+  const alreadyDisabled = existingArgs
+    .split(/\s+/)
+    .some(
+      arg =>
+        arg === MAVEN_NO_TRANSFER_PROGRESS_FLAG ||
+        arg === MAVEN_NO_TRANSFER_PROGRESS_LONG_FLAG
+    );
+
+  if (alreadyDisabled) {
+    core.debug(
+      `${MAVEN_ARGS_ENV} already disables transfer progress; leaving it unchanged`
+    );
+    return;
+  }
+
+  const updatedArgs = existingArgs
+    ? `${existingArgs} ${MAVEN_NO_TRANSFER_PROGRESS_FLAG}`
+    : MAVEN_NO_TRANSFER_PROGRESS_FLAG;
+
+  core.exportVariable(MAVEN_ARGS_ENV, updatedArgs);
+  core.info(
+    `Set ${MAVEN_ARGS_ENV} to '${updatedArgs}' to suppress Maven transfer progress logs. ` +
+      `Set 'show-download-progress: true' to keep the download progress output.`
+  );
+}

src/setup-java.ts

@@ -12,6 +12,7 @@ import {restore} from './cache';
 import * as path from 'path';
 import {getJavaDistribution} from './distributions/distribution-factory';
 import {JavaInstallerOptions} from './distributions/base-models';
+import {configureMavenArgs} from './maven-args';
 
 async function run() {
   try {
@@ -79,6 +80,7 @@ async function run() {
     core.info(`##[add-matcher]${path.join(matchersPath, 'java.json')}`);
 
     await auth.configureAuthentication();
+    configureMavenArgs();
     if (cache && isCacheFeatureAvailable()) {
       await restore(cache, cacheDependencyPath);
     }