Fix completion logic to only see words pertaining to args

spring-shell2-core/src/main/java/org/springframework/shell2/CompletionContext.java

@@ -16,6 +16,7 @@
 
 package org.springframework.shell2;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -78,4 +79,11 @@ public class CompletionContext {
 		String currentWord = currentWord();
 		return currentWord != null ? currentWord.substring(0, getPosition()) : null;
 	}
+
+	/**
+	 * Return a copy of this context, as if the first {@literal nbWords} were not present
+	 */
+	public CompletionContext drop(int nbWords) {
+		return new CompletionContext(new ArrayList<String>(words.subList(nbWords, words.size())), wordIndex-nbWords, position);
+	}
 }

spring-shell2-core/src/main/java/org/springframework/shell2/Shell.java

@@ -154,12 +154,13 @@ public class Shell implements CommandRegistry {
 			return candidates;
 		}
 
+		CompletionContext argsContext = context.drop(best.split(" ").length);
 		// Try to complete arguments
 		MethodTarget methodTarget = methodTargets.get(best);
 		Method method = methodTarget.getMethod();
 		return Arrays.stream(method.getParameters())
 			.map(Utils::createMethodParameter)
-			.flatMap(mp -> findResolver(mp).complete(mp, context).stream())
+			.flatMap(mp -> findResolver(mp).complete(mp, argsContext).stream())
 			.collect(Collectors.toList());
 	}