fix ash -jvm-debugger on java 8

src/main/resources/com/typesafe/sbt/packager/archetypes/scripts/ash-template

@@ -57,7 +57,12 @@ addResidual () {
 }
 
 addDebugger () {
-  addJava "-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:$1"
+  local major_version=$(get_java_major_version)
+  local address="*:$1"
+  if [ $major_version -le 8 ]; then
+    address="$1"
+  fi
+  addJava "-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=$address"
 }
 
 require_arg () {
@@ -69,6 +74,24 @@ require_arg () {
   fi
 }
 
+get_java_major_version () {
+  readonly java_version=$("$java_cmd" -version 2>&1 | awk -F '"' '/version/ {print $2}')
+  if [[ "$java_version" == "" ]]; then
+    echoerr "Could not determine Java version. Assuming 8."
+    echo 8
+  else
+    local major=$(echo "$java_version" | cut -d'.' -f1)
+    if [[ "$major" -eq "1" ]]; then
+      local major=$(echo "$java_version" | cut -d'.' -f2)
+    fi
+    echo $major
+  fi
+}
+
+echoerr () {
+  echo 1>&2 "$@"
+}
+
 # Allow user to specify java options. These get listed first per bash-template.
 if [ -n "$JAVA_OPTS" ]
 then
@@ -95,13 +118,16 @@ get_java_cmd() {
 # Processes incoming arguments and places them in appropriate global variables.  called by the run method.
 process_args () {
   local no_more_snp_opts=0
+  # this depends on -java-home, so we need to delay calling addDebugger until all opts have been parsed
+  local should_add_debugger=
+
   while [ $# -gt 0 ]; do
     case "$1" in
              --) shift && no_more_snp_opts=1 && break ;;
        -h|-help) usage; exit 1 ;;
 
            -mem) echo "!! WARNING !! -mem option is ignored. Please use -J-Xmx and -J-Xms" && shift 2 ;;
-     -jvm-debug) require_arg port "$1" "$2" && addDebugger $2 && shift 2 ;;
+     -jvm-debug) require_arg port "$1" "$2" && should_add_debugger=$2 && shift 2 ;;
 
           -main) custom_mainclass="$2" && shift 2 ;;
 
@@ -113,6 +139,10 @@ process_args () {
     esac
   done
 
+  if [[ $should_add_debugger ]]; then
+    addDebugger $should_add_debugger
+  fi
+
   if [ $no_more_snp_opts ]; then
     while [ $# -gt 0 ]; do
       addResidual "$1" && shift
@@ -158,6 +188,7 @@ app_mainclass=${{app_mainclass}}
 
 ${{template_declares}}
 
+java_cmd="$(get_java_cmd)"
 process_args "$@"
 
 # Fallback to custom mainclass if main class is not provided (this is the case if the JAR contains multiple apps)
@@ -170,8 +201,6 @@ if [ "$app_mainclass" = "" ] || [ $custom_mainclass ];then
   app_mainclass=$custom_mainclass
 fi
 
-java_cmd="$(get_java_cmd)"
-
 # If a configuration file exist, read the contents to $opts
 [ -f "$script_conf_file" ] && opts=$(loadConfigFile "$script_conf_file")
 

src/sbt-test/ash/script-debug/build.sbt

@@ -1,5 +1,3 @@
-import java.net.ServerSocket
-
 enablePlugins(JavaAppPackaging, AshScriptPlugin)
 
 name := "script-debug"

src/sbt-test/bash/script-debug/build.sbt

@@ -1,5 +1,3 @@
-import java.net.ServerSocket
-
 enablePlugins(JavaAppPackaging)
 
 name := "script-debug"