Missing argument for option -D, fixes #662 (#679)

Co-authored-by: 核桃 <hetao@2dfire.com>

client/src/main/java/org/mvndaemon/mvnd/client/DefaultClient.java

@@ -30,11 +30,14 @@ import java.time.format.DateTimeFormatter;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.EnumSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+
 import org.fusesource.jansi.Ansi;
 import org.fusesource.jansi.internal.CLibrary;
 import org.jline.utils.AttributedString;
@@ -139,9 +142,23 @@ public class DefaultClient implements Client {
     }
 
     public static void setSystemPropertiesFromCommandLine(List<String> args) {
-        for (String arg : args) {
+        final Iterator<String> iterator = args.iterator();
+        boolean defineIsEmpty = false;
+        while (iterator.hasNext()) {
+            final String arg = iterator.next();
             String val = Environment.MAVEN_DEFINE.removeCommandLineOption(new ArrayList<>(Collections.singletonList(arg)));
+            /* not -D or --define and pre define is empty */
+            if (val == null && defineIsEmpty) {
+                defineIsEmpty = false;
+                /* not all of Environment, use arg as pre define value */
+                val = maybeDefineCommandLineOption(arg) ? arg : "";
+            }
             if (val != null) {
+                /* empty -D or --define, next arg is value */
+                if (val.isEmpty() && iterator.hasNext()) {
+                    defineIsEmpty = true;
+                    continue;
+                }
                 if (val.isEmpty()) {
                     throw new IllegalArgumentException("Missing argument for option " + arg);
                 }
@@ -156,6 +173,14 @@ public class DefaultClient implements Client {
         }
     }
 
+    private static boolean maybeDefineCommandLineOption(String arg) {
+        // if arg maybe MAVEN_DEFINE value
+        return EnumSet.allOf(Environment.class)
+                .stream()
+                .filter(e -> e != Environment.MAVEN_DEFINE)
+                .noneMatch(e -> e.hasCommandLineOption(Collections.singletonList(arg)));
+    }
+
     public DefaultClient(DaemonParameters parameters) {
         // Those options are needed in order to be able to set the environment correctly
         this.parameters = parameters.withJdkJavaOpts(

integration-tests/src/test/java/org/mvndaemon/mvnd/it/MavenConfNativeIT.java

@@ -37,8 +37,9 @@ public class MavenConfNativeIT {
     @Test
     void version() throws IOException, InterruptedException {
         final TestClientOutput o = new TestClientOutput();
+        // this test also exercise the "-D foo=bar" syntax for defining properties
         client.execute(o, "org.apache.maven.plugins:maven-help-plugin:3.2.0:evaluate",
-                "-Dexpression=maven.conf", "-q", "-DforceStdout", "--raw-streams").assertSuccess();
+                "-D", "expression=maven.conf", "-q", "-DforceStdout", "--raw-streams").assertSuccess();
         String conf = parameters.mvndHome().resolve("mvn/conf").toString();
         assertTrue(o.getMessages().stream()
                 .anyMatch(m -> m.toString().contains(conf)), "Output should contain " + conf);