Repository: appsmithorg/appsmith
File: app/client/src/widgets/ListWidgetV2/widget/index.tsx (TypeScript)

Code before:
  generatePrimaryKeys = () => {
    const { listData, primaryKeys } = this.props;

    if (!listData) return [];

    return listData.map((datum, index) => {
      const key = primaryKeys?.[index];

      if (typeof key === "number" || typeof key === "string") {
        return key.toString();
      }

      const datumToHash = datum ?? index;

      return hash(datumToHash, { algorithm: "md5" });
    });
  };

  generateMetaWidgets = () => {
    const { listData } = this.props;
    const hasEmptyData = !listData || listData.length === 0;

    // Check if data is empty and generate empty meta widgets to prevent currentItem binding errors
    if (hasEmptyData) {
      this.previouslyHadEmptyData = true;
      this.generateEmptyMetaWidgets();

      return;
    }

    // Check if we're transitioning from empty data to non-empty data
    // In this case, we need to flush existing meta widgets to prevent conflicts
    if (this.previouslyHadEmptyData) {
      this.previouslyHadEmptyData = false;
      // Clear the meta widget cache to ensure fresh generation
      this.metaWidgetGenerator.resetCache();
    }

    const generatorOptions = this.metaWidgetGeneratorOptions();

    const { metaWidgets, propertyUpdates, removedMetaWidgetIds } =
      this.metaWidgetGenerator.withOptions(generatorOptions).generate();

    this.updateCurrentItemsViewBinding();
    const mainCanvasWidget = this.generateMainMetaCanvasWidget();

    this.syncMetaContainerNames();

    const updates: ModifyMetaWidgetPayload = {
      addOrUpdate: metaWidgets,
      deleteIds: removedMetaWidgetIds,

Review comment (suggestion):
Weird idea: what if instead of having a specific function for generating empty meta widgets; when data is empty or undefined we simply pass `[{}]` as data to the list widget generator. We just need the first row of widgets which it can produce. Not 100% sure if it would work or not but the idea is to play with the data property and make the existing logic work rather than handling it as a special case.

Code after:
        afterMetaWidgetGenerate: this.afterMetaWidgetGenerate,
      },
      isEmptyListWidgetCase,
    };
  };

  generatePrimaryKeys = () => {
    const { listData, primaryKeys } = this.props;

    if (!listData) return [];

    return listData.map((datum, index) => {
      const key = primaryKeys?.[index];

      if (typeof key === "number" || typeof key === "string") {
        return key.toString();
      }

      const datumToHash = datum ?? index;

      return hash(datumToHash, { algorithm: "md5" });
    });
  };

  generateMetaWidgets = () => {
    // The metaWidgetGeneratorOptions method already handles empty data
    // by providing [{}] when listData is empty, so we can use normal generation flow

    const generatorOptions = this.metaWidgetGeneratorOptions();

    const { metaWidgets, propertyUpdates, removedMetaWidgetIds } =
      this.metaWidgetGenerator.withOptions(generatorOptions).generate();

    this.updateCurrentItemsViewBinding();
    const mainCanvasWidget = this.generateMainMetaCanvasWidget();

    this.syncMetaContainerNames();

    const updates: ModifyMetaWidgetPayload = {
      addOrUpdate: metaWidgets,
      deleteIds: removedMetaWidgetIds,
      propertyUpdates,
    };

    /**
     * The else if condition checks if the List's canvas widget is present in the
     * metaWidgetChildrenStructure, if not then it tries to re-hydrate it with the
     * previously generated mainCanvasWidget.
     *
     * This handles a case where the inner List widget is dragged an dropped outside
     * the list widget and into the main canvas. This operation results into the calling