[table] fix: invalidate grid before rendering table when dimensions c…

…hange (#3888)

packages/table/src/table.tsx

@@ -810,6 +810,10 @@ export class Table extends AbstractComponent2<ITableProps, ITableState, ITableSn
             enableColumnInteractionBar,
         } = this.props;
         const { horizontalGuides, numFrozenColumnsClamped, numFrozenRowsClamped, verticalGuides } = this.state;
+        if (!this.gridDimensionsMatchProps()) {
+            // Ensure we're rendering the correct number of rows & columns
+            this.invalidateGrid();
+        }
         this.validateGrid();
 
         const classes = classNames(
@@ -993,6 +997,13 @@ export class Table extends AbstractComponent2<ITableProps, ITableState, ITableSn
         }
     }
 
+    private gridDimensionsMatchProps() {
+        const { children, numRows } = this.props;
+        return (
+            this.grid != null && this.grid.numCols === React.Children.count(children) && this.grid.numRows === numRows
+        );
+    }
+
     // Hotkeys
     // =======
 

packages/table/test/tableTests.tsx

@@ -582,6 +582,24 @@ describe("<Table>", function(this) {
             expect(onCompleteRenderSpy.callCount, "call count on update").to.equal(2);
         });
 
+        it("does not try to render cells that no longer exist", () => {
+            const onCompleteRenderSpy = sinon.spy();
+            let numRows = 2;
+            const cellRenderer = (rowIndex: number) => {
+                if (rowIndex >= numRows) {
+                    throw new Error(`There is no row with index ${rowIndex}`);
+                }
+                return <Cell>Row ${rowIndex}</Cell>;
+            };
+            const table = mount(
+                <Table numRows={numRows} onCompleteRender={onCompleteRenderSpy} renderMode={RenderMode.NONE}>
+                    <Column cellRenderer={cellRenderer} />
+                </Table>,
+            );
+            numRows = 1;
+            expect(() => table.setProps({ numRows })).does.not.throw();
+        });
+
         it("triggers immediately on mount with RenderMode.BATCH_ON_UPDATE", () => {
             const onCompleteRenderSpy = sinon.spy();
             mount(