Add busybox wget support as fallback in only-mvnw script

- Enhanced only-mvnw script to try busybox wget when neither wget nor curl is available
- Added busybox wget detection in all HTTP request functions:
  * resolve_jdk_url() for JDK URL resolution API calls
  * redirect URL resolution logic
  * get_latest_version_from_disco() for version API calls
  * install_jdk() for JDK file downloads
  * main Maven distribution download section
- Updated error messages to include busybox wget as supported option
- Updated integration tests to handle busybox wget error messages
- Improves compatibility with minimal Linux environments like Alpine containers

Author: gnodet

maven-wrapper-distribution/src/resources/only-mvnw

@@ -196,8 +196,10 @@ resolve_jdk_url() {
     _resolve_api_response="$(curl -s -f "$_resolve_disco_api_url" 2>/dev/null)"
   elif command -v wget >/dev/null; then
     _resolve_api_response="$(wget -q -O - "$_resolve_disco_api_url" 2>/dev/null)"
+  elif command -v busybox >/dev/null && busybox wget --help >/dev/null 2>&1; then
+    _resolve_api_response="$(busybox wget -q -O - "$_resolve_disco_api_url" 2>/dev/null)"
   else
-    die "Cannot resolve JDK URL: curl or wget required"
+    die "Cannot resolve JDK URL: curl, wget, or busybox wget required"
   fi
 
   if [ -z "$_resolve_api_response" ]; then
@@ -216,6 +218,8 @@ resolve_jdk_url() {
     _resolve_download_url="$(curl -s -I "$_resolve_redirect_url" 2>/dev/null | grep -i '^location:' | cut -d' ' -f2- | tr -d '\r\n')"
   elif command -v wget >/dev/null; then
     _resolve_download_url="$(wget -q -S -O /dev/null "$_resolve_redirect_url" 2>&1 | grep -i '^  location:' | cut -d' ' -f4- | tr -d '\r\n')"
+  elif command -v busybox >/dev/null && busybox wget --help >/dev/null 2>&1; then
+    _resolve_download_url="$(busybox wget -q -S -O /dev/null "$_resolve_redirect_url" 2>&1 | grep -i '^  location:' | cut -d' ' -f4- | tr -d '\r\n')"
   else
     # Fallback to using the redirect URL directly
     _resolve_download_url="$_resolve_redirect_url"
@@ -334,8 +338,10 @@ get_latest_version_from_disco() {
     api_response="$(curl -s -f "$disco_api_url" 2>/dev/null)"
   elif command -v wget >/dev/null; then
     api_response="$(wget -q -O - "$disco_api_url" 2>/dev/null)"
+  elif command -v busybox >/dev/null && busybox wget --help >/dev/null 2>&1; then
+    api_response="$(busybox wget -q -O - "$disco_api_url" 2>/dev/null)"
   else
-    verbose "No HTTP client (curl/wget) available for Disco API"
+    verbose "No HTTP client (curl/wget/busybox wget) available for Disco API"
     return 1 # No HTTP client available
   fi
 
@@ -508,8 +514,10 @@ install_jdk() {
     wget ${__MVNW_QUIET_WGET:+"$__MVNW_QUIET_WGET"} "$url" -O "$jdk_file" || die "wget: Failed to fetch JDK from $url"
   elif [ -z "${MVNW_USERNAME-}" ] && command -v curl >/dev/null; then
     curl ${__MVNW_QUIET_CURL:+"$__MVNW_QUIET_CURL"} -f -L -o "$jdk_file" "$url" || die "curl: Failed to fetch JDK from $url"
+  elif [ -z "${MVNW_USERNAME-}" ] && command -v busybox >/dev/null && busybox wget --help >/dev/null 2>&1; then
+    busybox wget ${__MVNW_QUIET_WGET:+"$__MVNW_QUIET_WGET"} "$url" -O "$jdk_file" || die "busybox wget: Failed to fetch JDK from $url"
   else
-    die "Cannot download JDK: wget or curl required"
+    die "Cannot download JDK: wget, curl, or busybox wget required"
   fi
 
   # Verify checksum if provided
@@ -670,6 +678,9 @@ if [ -z "${MVNW_USERNAME-}" ] && command -v wget >/dev/null; then
 elif [ -z "${MVNW_USERNAME-}" ] && command -v curl >/dev/null; then
   verbose "Found curl ... using curl"
   curl ${__MVNW_QUIET_CURL:+"$__MVNW_QUIET_CURL"} -f -L -o "$TMP_DOWNLOAD_DIR/$distributionUrlName" "$distributionUrl" || die "curl: Failed to fetch $distributionUrl"
+elif [ -z "${MVNW_USERNAME-}" ] && command -v busybox >/dev/null && busybox wget --help >/dev/null 2>&1; then
+  verbose "Found busybox wget ... using busybox wget"
+  busybox wget ${__MVNW_QUIET_WGET:+"$__MVNW_QUIET_WGET"} "$distributionUrl" -O "$TMP_DOWNLOAD_DIR/$distributionUrlName" || die "busybox wget: Failed to fetch $distributionUrl"
 elif set_java_home; then
   verbose "Falling back to use Java to download"
   javaSource="$TMP_DOWNLOAD_DIR/Downloader.java"

maven-wrapper-plugin/src/it/projects/jdk_checksum_verification/verify.groovy

@@ -44,7 +44,7 @@ assert log.contains('[INFO] Unpacked only-script type wrapper distribution')
 // 2. Network issues preventing download
 // 3. System JDK usage (if JDK download is skipped)
 boolean checksumFailure = log.contains("checksum") || log.contains("SHA-256") || log.contains("verification")
-boolean networkIssue = log.contains("Failed to fetch") || log.contains("curl:") || log.contains("wget:")
+boolean networkIssue = log.contains("Failed to fetch") || log.contains("curl:") || log.contains("wget:") || log.contains("busybox wget:")
 
 // The test should either fail checksum verification or use system JDK
 assert checksumFailure || networkIssue || systemJdkUsed, "Either checksum verification should occur, network issue encountered, or system JDK should be used"

maven-wrapper-plugin/src/it/projects/type_only-script-fail/verify.groovy

@@ -27,5 +27,5 @@ if (isWindows) {
 } else {
     // on non-Windows: verify clear messages as well
     // cover all methods: point is, there is no Maven version 0.0.0
-    assert log.contains('wget: Failed to fetch') || log.contains('curl: Failed to fetch') || log.contains('- Error downloading:')
+    assert log.contains('wget: Failed to fetch') || log.contains('curl: Failed to fetch') || log.contains('busybox wget: Failed to fetch') || log.contains('- Error downloading:')
 }