JetBrains/intellij-community · error · IllegalArgumentException

Row %d access failed: hierarchicalIdx cannot be empty

Error message

Row %d access failed: hierarchicalIdx cannot be empty

What it means

HierarchicalColumnsDataGridModel.validateHierarchicalIndex throws IllegalArgumentException when the hierarchical index array is non-null but empty (length == 0). An empty path addresses no column level, so traversal cannot even start; the message identifies the offending row number.

Source

Thrown at grid/core-impl/src/datagrid/HierarchicalColumnsDataGridModel.java:410

    return CsvImportUtil.getPreferredTypeMergerBasedOnContent(
      values, STRING_MERGER, INTEGER_MERGER, BIG_INTEGER_MERGER, DOUBLE_MERGER, BOOLEAN_MERGER);
  }

  private static Object getValue(GridRow row, int[] hierarchicalIdx) {
    validateHierarchicalIndex(hierarchicalIdx, row.getRowNum());
    return tryExtractValueByHierarchicalIndex(GridRow.getValues(row), hierarchicalIdx, row.getRowNum());
  }

  private static void validateHierarchicalIndex(int[] hierarchicalIdx, int rowNum) {
    if (hierarchicalIdx == null) {
      throw new IllegalArgumentException(
        String.format("Row %d failed: hierarchicalIdx cannot be null", rowNum)
      );
    }

    if (hierarchicalIdx.length == 0) {
      throw new IllegalArgumentException(
        String.format("Row %d access failed: hierarchicalIdx cannot be empty", rowNum)
      );
    }
  }

  private static @Nullable Object tryExtractValueByHierarchicalIndex(Object[] topLevelValues, int[] hierarchicalIdx, int rowNum) {
    try {
      return extractValueByHierarchicalIndex(topLevelValues, hierarchicalIdx);
    } catch (IndexOutOfBoundsException | NullPointerException | IllegalArgumentException e) {
      throw new RuntimeException(String.format("Row %d access failed: %s", rowNum, e.getMessage()), e);
    }
  }

  public static Object extractValueByHierarchicalIndex(Object[] topLevelValues, int[] hierarchicalIdx) {
    Object result = null;
    Object[] data = topLevelValues;
    for (int i = 0; i < hierarchicalIdx.length; ++i) {
      int idx = hierarchicalIdx[i];

View on GitHub (pinned to be881553f2)

Solutions

1. Ensure every column has at least one level in its hierarchical path (top-level columns get a single-element array like [colIdx]).
2. Skip hierarchical access for columns without a path and use the flat index instead.
3. Assert path.length > 0 when building/validating column definitions, before any row access.

Example fix

// before
int[] idx = levels.toArray(new int[0]); // empty for top-level
getValue(row, idx);

// after
int[] idx = levels.isEmpty() ? new int[]{flatColIdx} : levels.stream().mapToInt(Integer::intValue).toArray();
getValue(row, idx);

if (hierarchicalIdx == null || hierarchicalIdx.length == 0) {
  hierarchicalIdx = new int[]{column.getFlatIdx()};
}

static boolean isUsableIdx(@Nullable int[] idx) { return idx != null && idx.length > 0; }

When it happens

Trigger: Calling hierarchical value access with new int[0] — e.g. a column whose hierarchy path was never populated (root-only column) or a list-of-levels that was filtered to empty.

Common situations: Columns built programmatically without a hierarchy path; data-driven column definitions where the path list is empty for top-level columns and code converts it to an array unconditionally.

Related errors

• Row %d failed: hierarchicalIdx cannot be null
• Row %d access failed: %s
• Access by hierarchical idx %s failed: Index out of bounds at
• Access by hierarchical idx %s failed: Encountered a null ele
• Access by hierarchical idx %s failed: Encountered an unexpec

AI-assisted analysis of JetBrains/intellij-community@be881553f2 (2026-08-14). Data as JSON: /api/errors/308e709a0d3d39e0. Report an issue: GitHub.