I/6346: TableSelection should work with external changes.

src/tableselection.js

@@ -103,7 +103,7 @@ export default class TableSelection extends Plugin {
 
 		setupTableSelectionHighlighting( editor, this );
 
-		this.listenTo( selection, 'change:range', () => this._clearSelectionOnExternalChange( selection ) );
+		this.listenTo( selection, 'change:range', () => this._checkSelectionOnExternalChange(), { priority: 'highest' } );
 		this.listenTo( model, 'deleteContent', ( evt, args ) => this._handleDeleteContent( evt, args ), { priority: 'high' } );
 	}
 
@@ -296,14 +296,31 @@ export default class TableSelection extends Plugin {
 	}
 
 	/**
-	 * Checks if the selection has changed via an external change and if it is required to clear the internal state of the plugin.
+	 * Checks if the selection has changed via an external change and if it is required to update the internal state of the plugin.
 	 *
-	 * @param {module:engine/model/documentselection~DocumentSelection} selection
 	 * @private
 	 */
-	_clearSelectionOnExternalChange( selection ) {
+	_checkSelectionOnExternalChange() {
+		const model = this.editor.model;
+		const selection = model.document.selection;
+
 		if ( selection.rangeCount <= 1 && this.hasMultiCellSelection ) {
 			this.clearSelection();
+
+			return;
+		}
+
+		const tableCells = Array.from( selection.getSelectedBlocks() )
+			.map( element => findAncestor( 'tableCell', model.createPositionAt( element, 0 ) ) )
+			.filter( tableCell => !!tableCell );
+
+		const size = tableCells.length;
+
+		if ( !this.hasMultiCellSelection && size ) {
+			// this is undo or external change to the selection so "fix" internal state.
+
+			this._startElement = tableCells[ 0 ];
+			this._endElement = tableCells[ tableCells.length - 1 ];
 		}
 	}
 

tests/tableselection-integration.js

@@ -18,6 +18,7 @@ import ClassicTestEditor from '@ckeditor/ckeditor5-core/tests/_utils/classictest
 import { getCode } from '@ckeditor/ckeditor5-utils/src/keyboard';
 import Input from '@ckeditor/ckeditor5-typing/src/input';
 import ViewText from '@ckeditor/ckeditor5-engine/src/view/text';
+import UndoEditing from '@ckeditor/ckeditor5-undo/src/undoediting';
 
 describe( 'table selection', () => {
 	let editor, model, tableSelection, modelRoot, element, viewDocument;
@@ -151,6 +152,48 @@ describe( 'table selection', () => {
 		} );
 	} );
 
+	describe( 'TableSelection - undo integration', () => {
+		afterEach( async () => {
+			element.remove();
+			await editor.destroy();
+		} );
+
+		describe( 'on undo', () => {
+			beforeEach( async () => {
+				await setupEditor( [ Input, UndoEditing ] );
+			} );
+
+			it( 'should clear contents of the selected table cells and put selection in last cell on backward delete', () => {
+				tableSelection.startSelectingFrom( modelRoot.getNodeByPath( [ 0, 0, 0 ] ) );
+				tableSelection.setSelectingTo( modelRoot.getNodeByPath( [ 0, 1, 1 ] ) );
+
+				const node = modelRoot.getNodeByPath( [ 0, 0, 0, 0 ] );
+				editor.execute( 'input', {
+					text: 'foobar',
+					range: model.createRangeIn( modelRoot.getNodeByPath( [ 0, 0, 0, 0 ] ) ),
+					resultRange: model.createRange(
+						model.createPositionAt( node, 0 ),
+						model.createPositionAt( node, 0 )
+					)
+				} );
+
+				assertEqualMarkup( getModelData( model, { withoutSelection: true } ), modelTable( [
+					[ 'foobar', '12', '13' ],
+					[ '21', '22', '23' ],
+					[ '31', '32', '33' ]
+				] ) );
+
+				editor.execute( 'undo' );
+
+				assertEqualMarkup( getModelData( model ), modelTable( [
+					[ { contents: '11', isSelected: true }, { contents: '12', isSelected: true }, '13' ],
+					[ { contents: '21', isSelected: true }, { contents: '22', isSelected: true }, '23' ],
+					[ '31', '32', '33' ]
+				] ) );
+			} );
+		} );
+	} );
+
 	async function setupEditor( plugins ) {
 		element = document.createElement( 'div' );
 		document.body.appendChild( element );