public Builder mergeFrom(main.Messages.ExecuteStepRequest other) {
        if (other == main.Messages.ExecuteStepRequest.getDefaultInstance()) return this;
        if (other.hasStepText()) {
          bitField0_ |= 0x00000001;
          stepText_ = other.stepText_;
          onChanged();
        }
        if (other.hasScenarioFailing()) {
          setScenarioFailing(other.getScenarioFailing());
        }
        if (argsBuilder_ == null) {
          if (!other.args_.isEmpty()) {
            if (args_.isEmpty()) {
              args_ = other.args_;
              bitField0_ = (bitField0_ & ~0x00000004);
            } else {
              ensureArgsIsMutable();
              args_.addAll(other.args_);
            }
            onChanged();
          }
        } else {
          if (!other.args_.isEmpty()) {
            if (argsBuilder_.isEmpty()) {
              argsBuilder_.dispose();
              argsBuilder_ = null;
              args_ = other.args_;
              bitField0_ = (bitField0_ & ~0x00000004);
              argsBuilder_ = 
                com.google.protobuf.GeneratedMessage.alwaysUseFieldBuilders ?
                   getArgsFieldBuilder() : null;
            } else {
              argsBuilder_.addAllMessages(other.args_);
            }
          }
        }
        this.mergeUnknownFields(other.getUnknownFields());
        return this;
      }