fix long name option completion. close #318

core/src/main/java/com/taobao/arthas/core/shell/cli/CompletionUtils.java

@@ -99,7 +99,12 @@ public class CompletionUtils {
         } else {
             String commonPrefix = CompletionUtils.findLongestCommonPrefix(candidates);
             if (commonPrefix.length() > 0) {
-                completion.complete(commonPrefix, false);
+                if (commonPrefix.length() == prefix.length()) {
+                    completion.complete(candidates);
+                } else {
+                    completion.complete(commonPrefix.substring(prefix.length(), commonPrefix.length()), false);
+                }
+
             } else {
                 completion.complete(candidates);
             }

core/src/main/java/com/taobao/arthas/core/shell/term/impl/CompletionAdaptor.java

@@ -49,9 +49,11 @@ class CompletionAdaptor implements Completion {
                 CliToken lastToken = tokens.get(tokens.size() - 1);
                 if (!commonPrefix.equals(lastToken.value())) {
                     // only complete if the common prefix is longer than the last token
-                    String strToComplete = commonPrefix.substring(lastToken.value().length());
+                    if (commonPrefix.length() > lastToken.value().length()) {
-                    completion.complete(io.termd.core.util.Helper.toCodePoints(strToComplete), false);
+                        String strToComplete = commonPrefix.substring(lastToken.value().length());
-                    return;
+                        completion.complete(io.termd.core.util.Helper.toCodePoints(strToComplete), false);
+                        return;
+                    }
                 }
             }
         }