Exclude focused block from block completer options

editor/components/autocompleters/block.js

@@ -10,12 +10,34 @@ import { createBlock } from '@wordpress/blocks';
 import './style.scss';
 import BlockIcon from '../block-icon';
 
-function defaultGetBlockInsertionPoint() {
-	return select( 'core/editor' ).getBlockInsertionPoint();
+/**
+ * Get the UID of the parent where a newly inserted block would be placed.
+ *
+ * @return {string} The UID of the parent where a newly inserted block would be placed.
+ */
+function defaultGetBlockInsertionParent() {
+	return select( 'core/editor' ).getBlockInsertionPoint().rootUID;
+}
+
+/**
+ * Get the inserter items for the specified parent block.
+ *
+ * @param {string} parentUID The UID of the block for which to retrieve inserter items.
+ *
+ * @return {Array<Editor.InserterItem>} The inserter items for the specified parent.
+ */
+function defaultGetInserterItems( parentUID ) {
+	return select( 'core/editor' ).getInserterItems( parentUID );
 }
 
-function defaultGetInserterItems( { rootUID } ) {
-	return select( 'core/editor' ).getInserterItems( rootUID );
+/**
+ * Get the name of the currently selected block.
+ *
+ * @return {string?} The name of the currently selected block or `null` if no block is selected.
+ */
+function defaultGetSelectedBlockName() {
+	const selectedBlock = select( 'core/editor' ).getSelectedBlock();
+	return selectedBlock ? selectedBlock.name : null;
 }
 
 /**
@@ -25,15 +47,20 @@ function defaultGetInserterItems( { rootUID } ) {
  */
 export function createBlockCompleter( {
 	// Allow store-based selectors to be overridden for unit test.
-	getBlockInsertionPoint = defaultGetBlockInsertionPoint,
+	getBlockInsertionParent = defaultGetBlockInsertionParent,
 	getInserterItems = defaultGetInserterItems,
+	getSelectedBlockName = defaultGetSelectedBlockName,
 } = {} ) {
 	return {
 		name: 'blocks',
 		className: 'editor-autocompleters__block',
 		triggerPrefix: '/',
 		options() {
-			return getInserterItems( getBlockInsertionPoint() );
+			const selectedBlockName = getSelectedBlockName();
+			return getInserterItems( getBlockInsertionParent() ).filter(
+				// Avoid offering to replace the current block with a block of the same type.
+				( inserterItem ) => selectedBlockName !== inserterItem.name
+			);
 		},
 		getOptionKeywords( inserterItem ) {
 			const { title, keywords = [] } = inserterItem;

editor/components/autocompleters/test/block.js

@@ -11,18 +11,33 @@ import blockCompleter, { createBlockCompleter } from '../block';
 describe( 'block', () => {
 	it( 'should retrieve block options for current insertion point', () => {
 		const expectedOptions = [ {}, {}, {} ];
-		const mockGetBlockInsertionPoint = jest.fn( () => 'expected-insertion-point' );
+		const mockGetBlockInsertionParent = jest.fn( () => 'expected-insertion-point' );
 		const mockGetInserterItems = jest.fn( () => expectedOptions );
 
 		const completer = createBlockCompleter( {
-			getBlockInsertionPoint: mockGetBlockInsertionPoint,
+			getBlockInsertionParent: mockGetBlockInsertionParent,
 			getInserterItems: mockGetInserterItems,
+			getSelectedBlockName: () => 'non-existent-block-name',
 		} );
 
 		const actualOptions = completer.options();
-		expect( mockGetBlockInsertionPoint ).toHaveBeenCalled();
+		expect( mockGetBlockInsertionParent ).toHaveBeenCalled();
 		expect( mockGetInserterItems ).toHaveBeenCalledWith( 'expected-insertion-point' );
-		expect( actualOptions ).toBe( expectedOptions );
+		expect( actualOptions ).toEqual( expectedOptions );
+	} );
+
+	it( 'should exclude the currently selected block from the options', () => {
+		const option1 = { name: 'block-1' };
+		const option2CurrentlySelected = { name: 'block-2-currently-selected' };
+		const option3 = { name: 'block-3' };
+
+		const completer = createBlockCompleter( {
+			getBlockInsertionParent: () => 'ignored',
+			getInserterItems: () => [ option1, option2CurrentlySelected, option3 ],
+			getSelectedBlockName: () => 'block-2-currently-selected',
+		} );
+
+		expect( completer.options() ).toEqual( [ option1, option3 ] );
 	} );
 
 	it( 'should derive option keywords from block keywords and block title', () => {