JetBrains/intellij-community · error · IllegalStateException

The setColumns operation can only be performed on top-level

Error message

The setColumns operation can only be performed on top-level tables. Nested tables do not support this operation because the column structure of nested tables is encapsulated within the nested table object.

What it means

NestedTablesDataGridModel.setColumns throws IllegalStateException when a nested table is currently selected. Column structure of nested tables lives inside the NestedTable value itself, so replacing the top-level column list from within a drilled-down view is disallowed.

Source

Thrown at grid/core-impl/src/datagrid/NestedTablesDataGridModel.java:244

  }

  @Override
  public void removeRows(int firstRowIndex, int rowCount) {
    if (isTopLevelGrid()) {
      myModel.removeRows(firstRowIndex, rowCount);
      return;
    }
    for (int i = firstRowIndex + rowCount - 1; i >= firstRowIndex; --i) {
      myCurrentlySelectedNestedTable.removeRow(i);
    }
    myRowsCache.clearCache(myCurrentlySelectedNestedTable);
    updateNestedTableSelection();
  }

  @Override
  public void setColumns(@NotNull List<? extends GridColumn> columns) {
    if (!isTopLevelGrid()) {
      throw new IllegalStateException(
        "The setColumns operation can only be performed on top-level tables. Nested tables do not support this operation because the column structure of nested tables is encapsulated within the nested table object.");
    }
    myModel.setColumns(columns);
    clearCaches();
  }

  @Override
  public void clearColumns() {
    if (!isTopLevelGrid()) {
      throw new IllegalStateException(
        "The setColumns operation can only be performed on top-level tables. Nested tables do not support this operation because the column structure of nested tables is encapsulated within the nested table object.");
    }
    myModel.clearColumns();
    clearCaches();
  }

  @Override
  public void set(int i, GridRow objects) {

View on GitHub (pinned to be881553f2)

Solutions

Exit the nested view first (clear nested selection / pop path coordinates) before setColumns.
Guard with isTopLevelGrid() and defer or queue the column update until the user returns to the top level.
For a full reload, reset the whole nested-navigation state instead of only swapping columns.

Example fix

// before
model.setColumns(newColumns);

// after
while (!model.isTopLevelGrid()) {
  model.removeLastNCellCoordinates(1);
}
model.setColumns(newColumns);

Defensive patterns

Strategy: validation

Validate before calling

if (!model.isTopLevelGrid()) {
  while (!model.isTopLevelGrid()) model.removeLastNCellCoordinates(1);
}
model.setColumns(newColumns);

Prevention

Exit the nested view (pop all coordinates) before any schema mutation.
Defer column updates triggered by background reloads until the top-level view is active.

When it happens

Trigger: Calling setColumns(columns) while the user is inside a nested grid (navigation path non-empty), e.g. a schema-refresh routine that does not account for drill-down state.

Common situations: Reload/refresh actions firing while a nested table is open; automated pipelines calling setColumns without resetting the nested-table selection first.

Related errors

AI-assisted analysis of JetBrains/intellij-community@be881553f2 (2026-08-14). Data as JSON: /api/errors/59c6cde69d33ad72. Report an issue: GitHub.