useBlockSync(): Reset inner blocks when component unmounts

packages/block-editor/src/components/provider/test/use-block-sync.js

@@ -48,7 +48,7 @@ describe( 'useBlockSync hook', () => {
 		jest.clearAllMocks();
 	} );
 
-	it( 'resets the block-editor blocks when the controll value changes', async () => {
+	it( 'resets the block-editor blocks when the controlled value changes', async () => {
 		const fakeBlocks = [];
 		const resetBlocks = jest.spyOn( blockEditorActions, 'resetBlocks' );
 		const replaceInnerBlocks = jest.spyOn(
@@ -58,7 +58,7 @@ describe( 'useBlockSync hook', () => {
 		const onChange = jest.fn();
 		const onInput = jest.fn();
 
-		const { rerender } = render(
+		const { rerender, unmount } = render(
 			<TestWrapper
 				value={ fakeBlocks }
 				onChange={ onChange }
@@ -88,9 +88,16 @@ describe( 'useBlockSync hook', () => {
 		expect( onInput ).not.toHaveBeenCalled();
 		expect( replaceInnerBlocks ).not.toHaveBeenCalled();
 		expect( resetBlocks ).toHaveBeenCalledWith( testBlocks );
+
+		unmount();
+
+		expect( onChange ).not.toHaveBeenCalled();
+		expect( onInput ).not.toHaveBeenCalled();
+		expect( replaceInnerBlocks ).not.toHaveBeenCalled();
+		expect( resetBlocks ).toHaveBeenCalledWith( [] );
 	} );
 
-	it( 'replaces the inner blocks of a block when the control value changes if a clientId is passed', async () => {
+	it( 'replaces the inner blocks of a block when the controlled value changes if a clientId is passed', async () => {
 		const fakeBlocks = [];
 		const replaceInnerBlocks = jest.spyOn(
 			blockEditorActions,
@@ -100,7 +107,7 @@ describe( 'useBlockSync hook', () => {
 		const onChange = jest.fn();
 		const onInput = jest.fn();
 
-		const { rerender } = render(
+		const { rerender, unmount } = render(
 			<TestWrapper
 				clientId="test"
 				value={ fakeBlocks }
@@ -138,8 +145,16 @@ describe( 'useBlockSync hook', () => {
 		expect( onChange ).not.toHaveBeenCalled();
 		expect( onInput ).not.toHaveBeenCalled();
 		expect( resetBlocks ).not.toHaveBeenCalled();
-		// We can't check the args because the blocks are cloned.
-		expect( replaceInnerBlocks ).toHaveBeenCalled();
+		expect( replaceInnerBlocks ).toHaveBeenCalledWith( 'test', [
+			expect.objectContaining( { name: 'test/test-block' } ),
+		] );
+
+		unmount();
+
+		expect( onChange ).not.toHaveBeenCalled();
+		expect( onInput ).not.toHaveBeenCalled();
+		expect( resetBlocks ).not.toHaveBeenCalled();
+		expect( replaceInnerBlocks ).toHaveBeenCalledWith( 'test', [] );
 	} );
 
 	it( 'does not add the controlled blocks to the block-editor store if the store already contains them', async () => {

packages/block-editor/src/components/provider/use-block-sync.js

@@ -134,6 +134,19 @@ export default function useBlockSync( {
 		}
 	};
 
+	// Clean up the changes made by setControlledBlocks() when the component
+	// containing useBlockSync() unmounts.
+	const unsetControlledBlocks = () => {
+		__unstableMarkNextChangeAsNotPersistent();
+		if ( clientId ) {
+			setHasControlledInnerBlocks( clientId, false );
+			__unstableMarkNextChangeAsNotPersistent();
+			replaceInnerBlocks( clientId, [] );
+		} else {
+			resetBlocks( [] );
+		}
+	};
+
 	// Add a subscription to the block-editor registry to detect when changes
 	// have been made. This lets us inform the data source of changes. This
 	// is an effect so that the subscriber can run synchronously without
@@ -287,4 +300,10 @@ export default function useBlockSync( {
 			unsubscribe();
 		};
 	}, [ registry, clientId ] );
+
+	useEffect( () => {
+		return () => {
+			unsetControlledBlocks();
+		};
+	}, [] );
 }