[two_dimensional_scrollables] Add pinned extent assertions

packages/two_dimensional_scrollables/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+* Adds assertions against pinned row and column configurations that exceed the viewport or block additional cells.
+
 ## 0.0.3
 
 * Fixes paint issue when axes are reversed and TableView has pinned rows and columns.

packages/two_dimensional_scrollables/lib/src/table_view/table.dart

@@ -588,6 +588,58 @@ class RenderTableViewport extends RenderTwoDimensionalViewport {
     }
   }
 
+  bool _debugCheckPinnedSpanExtents() {
+    // Ensure pinned spans do not exceed the viewport dimensions. Pinned spans
+    // do not scroll.
+    assert(
+      _pinnedRowsExtent <= viewportDimension.height,
+      'The extent of pinned rows has overflowed the viewport by '
+      '${_pinnedRowsExtent - viewportDimension.height} pixels.',
+    );
+    assert(
+      _pinnedColumnsExtent <= viewportDimension.width,
+      'The extent of pinned columns has overflowed the viewport by '
+      '${_pinnedColumnsExtent - viewportDimension.width} pixels.',
+    );
+    // If pinned rows or columns take up the full extent of the viewport, and
+    // there are additional rows and columns that follow,
+    assert(() {
+      if (_pinnedRowsExtent == viewportDimension.height &&
+          _firstNonPinnedRow != null) {
+        throw FlutterError.fromParts(<DiagnosticsNode>[
+          ErrorSummary(
+            'The extent of pinned rows in the TableView has consumed the '
+            'full extent of the viewport.',
+          ),
+          ErrorDescription(
+            'The unpinned rows that follow will not be visible in the '
+            'viewport as the pinned extent has taken up all of the '
+            'available space.\n',
+          ),
+        ]);
+      }
+      return true;
+    }());
+    assert(() {
+      if (_pinnedColumnsExtent == viewportDimension.width &&
+          _firstNonPinnedColumn != null) {
+        throw FlutterError.fromParts(<DiagnosticsNode>[
+          ErrorSummary(
+            'The extent of pinned columns in the TableView has consumed the '
+            'full extent of the viewport.',
+          ),
+          ErrorDescription(
+            'The unpinned columns that follow will not be visible in the '
+            'viewport as the pinned extent has taken up all of the '
+            'available space.\n',
+          ),
+        ]);
+      }
+      return true;
+    }());
+    return true;
+  }
+
   @override
   void layoutChildSequence() {
     if (needsDelegateRebuild || didResize) {
@@ -605,6 +657,8 @@ class RenderTableViewport extends RenderTwoDimensionalViewport {
       return;
     }
 
+    assert(_debugCheckPinnedSpanExtents());
+
     final double? offsetIntoColumn = _firstNonPinnedColumn != null
         ? horizontalOffset.pixels -
             _columnMetrics[_firstNonPinnedColumn]!.leadingOffset -

packages/two_dimensional_scrollables/test/table_view/table_test.dart

@@ -4,6 +4,7 @@
 
 import 'dart:io' show Platform;
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
@@ -1159,6 +1160,167 @@ void main() {
         SystemMouseCursors.basic,
       );
     });
+
+    testWidgets('asserts pinned span extents cannot exceed viewport dimensions',
+        (WidgetTester tester) async {
+      final List<Object> exceptions = <Object>[];
+      final FlutterExceptionHandler? oldHandler = FlutterError.onError;
+      FlutterError.onError = (FlutterErrorDetails details) {
+        exceptions.add(details.exception);
+      };
+      // Row
+      TableView tableView = TableView.builder(
+        rowCount: 1,
+        columnCount: 1,
+        pinnedRowCount: 1,
+        pinnedColumnCount: 1,
+        rowBuilder: (int index) => const TableSpan(
+          // Exceeds the viewport height.
+          extent: FixedTableSpanExtent(1000),
+        ),
+        columnBuilder: (int index) => span,
+        cellBuilder: (BuildContext context, TableVicinity vicinty) => cell,
+      );
+
+      await tester.pumpWidget(MaterialApp(home: tableView));
+      FlutterError.onError = oldHandler;
+      expect(exceptions.length, 2);
+      expect(
+        exceptions[0].toString(),
+        contains('The extent of pinned rows has overflowed the viewport'),
+      );
+
+      await tester.pumpWidget(Container());
+      exceptions.clear();
+      FlutterError.onError = (FlutterErrorDetails details) {
+        exceptions.add(details.exception);
+      };
+      // Column
+      tableView = TableView.builder(
+        rowCount: 1,
+        columnCount: 1,
+        pinnedRowCount: 1,
+        pinnedColumnCount: 1,
+        columnBuilder: (int index) => const TableSpan(
+          // Exceeds the viewport height.
+          extent: FixedTableSpanExtent(1000),
+        ),
+        rowBuilder: (int index) => span,
+        cellBuilder: (BuildContext context, TableVicinity vicinty) => cell,
+      );
+
+      await tester.pumpWidget(MaterialApp(home: tableView));
+      FlutterError.onError = oldHandler;
+      expect(exceptions.length, 2);
+      expect(
+        exceptions[0].toString(),
+        contains('The extent of pinned columns has overflowed the viewport'),
+      );
+    });
+
+    testWidgets('asserts for pinned spans that block additional unpinned spans',
+        (WidgetTester tester) async {
+      final List<Object> exceptions = <Object>[];
+      final FlutterExceptionHandler? oldHandler = FlutterError.onError;
+      FlutterError.onError = (FlutterErrorDetails details) {
+        exceptions.add(details.exception);
+      };
+
+      // Row ----------
+      TableView tableView = TableView.builder(
+        rowCount: 1,
+        columnCount: 1,
+        pinnedRowCount: 1,
+        pinnedColumnCount: 1,
+        rowBuilder: (int index) => const TableSpan(
+          // Exceeds the viewport height.
+          extent: FixedTableSpanExtent(600), // == viewportDimension.height
+        ),
+        columnBuilder: (int index) => span,
+        cellBuilder: (BuildContext context, TableVicinity vicinty) => cell,
+      );
+
+      await tester.pumpWidget(MaterialApp(home: tableView));
+      FlutterError.onError = oldHandler;
+      // No additional rows, so this is ok.
+      expect(exceptions.length, 0);
+      FlutterError.onError = (FlutterErrorDetails details) {
+        exceptions.add(details.exception);
+      };
+      tableView = TableView.builder(
+        rowCount: 2, // One row would be obscured
+        columnCount: 1,
+        pinnedRowCount: 1,
+        pinnedColumnCount: 1,
+        rowBuilder: (int index) => const TableSpan(
+          // Exceeds the viewport height.
+          extent: FixedTableSpanExtent(600), // == viewportDimension.height
+        ),
+        columnBuilder: (int index) => span,
+        cellBuilder: (BuildContext context, TableVicinity vicinty) => cell,
+      );
+
+      await tester.pumpWidget(MaterialApp(home: tableView));
+      FlutterError.onError = oldHandler;
+      expect(exceptions.length, 2);
+      expect(
+        exceptions[0].toString(),
+        contains(
+          'The extent of pinned rows in the TableView has consumed the full '
+          'extent of the viewport.',
+        ),
+      );
+
+      await tester.pumpWidget(Container());
+      exceptions.clear();
+      FlutterError.onError = (FlutterErrorDetails details) {
+        exceptions.add(details.exception);
+      };
+      // Column ----------
+      tableView = TableView.builder(
+        rowCount: 1,
+        columnCount: 1,
+        pinnedRowCount: 1,
+        pinnedColumnCount: 1,
+        columnBuilder: (int index) => const TableSpan(
+          // Exceeds the viewport height.
+          extent: FixedTableSpanExtent(800), // == viewportDimension.width
+        ),
+        rowBuilder: (int index) => span,
+        cellBuilder: (BuildContext context, TableVicinity vicinty) => cell,
+      );
+
+      await tester.pumpWidget(MaterialApp(home: tableView));
+      FlutterError.onError = oldHandler;
+      // No additional rows, so this is ok.
+      expect(exceptions.length, 0);
+      FlutterError.onError = (FlutterErrorDetails details) {
+        exceptions.add(details.exception);
+      };
+      tableView = TableView.builder(
+        rowCount: 1,
+        columnCount: 2, // One column would be obscured
+        pinnedRowCount: 1,
+        pinnedColumnCount: 1,
+        columnBuilder: (int index) => const TableSpan(
+          // Exceeds the viewport height.
+          extent: FixedTableSpanExtent(800), // == viewportDimension.height
+        ),
+        rowBuilder: (int index) => span,
+        cellBuilder: (BuildContext context, TableVicinity vicinty) => cell,
+      );
+
+      await tester.pumpWidget(MaterialApp(home: tableView));
+      FlutterError.onError = oldHandler;
+      expect(exceptions.length, 2);
+      expect(
+        exceptions[0].toString(),
+        contains(
+          'The extent of pinned columns in the TableView has consumed the full '
+          'extent of the viewport.',
+        ),
+      );
+    });
   });
 }