Merge trunk — 3.6.11 shipped; keep 3.7.0 as the unreleased section

Conflicts in changelog.txt and readme.txt, identical in both files.

trunk released 3.6.11 on 2026-08-05 carrying the WOOTAX-74 fix ("incomplete
tax response") that this branch still listed as unreleased, plus the React 19
store-notices fix. This branch had both that line and its own Tweak under an
unreleased 3.7.0 heading.

Resolution: 3.6.11 stays verbatim as shipped history, and the WOOTAX-74 line is
dropped from the unreleased section rather than duplicated across two versions.
3.7.0 keeps only this PR's Tweak entry, dated 2026-xx-xx for woorelease to fill.

3.7.0 remains the right target — it is still greater than the newly released
3.6.11, and it matches the five `@since 3.7.0` stamps already on the branch.
`Stable tag` and the plugin Version header auto-merged to 3.6.11, which is
correct; woorelease bumps them at release time.

Suite: 252 tests, 543 assertions, green.

Author: bartech

.eslintrc.js

@@ -23,4 +23,29 @@ Object.assign( calypsoLintConfig.globals, {
     global: true,
 });
 
+// The store notices bundle is rendered by the React that WordPress provides, inside the
+// Cart/Checkout blocks. React 19 rejects elements created by an older React runtime, so
+// importing the plugin's bundled React here would break the block cart and checkout.
+// Everything in this tree must build its elements with window.wp.element instead.
+calypsoLintConfig.overrides = [
+    ...( calypsoLintConfig.overrides || [] ),
+    {
+        files: [ 'client/store-notices.js', 'client/components/store/notices/*.js' ],
+        rules: {
+            'no-restricted-imports': [
+                'error',
+                {
+                    paths: [
+                        {
+                            name: 'react',
+                            message:
+                                'This tree is rendered by the host React: build elements with window.wp.element instead. See client/store-notices.js.',
+                        },
+                    ],
+                },
+            ],
+        },
+    },
+];
+
 module.exports = useE2EEsLintConfig( calypsoLintConfig );

changelog.txt

@@ -1,9 +1,12 @@
 *** WooCommerce Tax Changelog ***
 
 = 3.7.0 - 2026-xx-xx =
-* Fix   - Prevent a fatal error during cart and checkout tax calculation when TaxJar returns an incomplete tax response.
 * Tweak - Reduce redundant TaxJar API calls by matching cached tax responses across the cart and order paths and ignoring irrelevant formatting differences.
 
+= 3.6.11 - 2026-08-05 =
+* Fix   - Prevent a fatal error during cart and checkout tax calculation when TaxJar returns an incomplete tax response.
+* Fix   - React 19 compatibility for store notices on the block cart and checkout.
+
 = 3.6.10 - 2026-07-27 =
 * Tweak - WooCommerce 11.0 Compatibility.
 

client/components/store/notices/store-notices.js

@@ -1,7 +1,10 @@
 /**
- * External dependencies
+ * This component is rendered by the host React inside the Cart/Checkout blocks, so it must
+ * not import the plugin's bundled React or return JSX built with it: React 19 rejects
+ * elements created by an older React runtime. Hooks and elements come from window.wp.*.
+ *
+ * @see ../../../store-notices.js
  */
-import React from 'react';
 
 const { useDispatch, useSelect } = window.wp.data;
 const { useEffect }              = window.wp.element;
@@ -19,7 +22,7 @@ const noticeIdPrefix = 'wcservices-store-notices-';
  * @param {Object} props.extensions - An object containing store API response data related for all extensions.
  * @param {Object} props.cart - An object containing details about the cart.
  *
- * @returns {JSX.Element} - An empty React fragment.
+ * @returns {null} - Nothing is rendered; the component only manages notices.
  */
 export const StoreNotices = ( {
 	extensions, cart,
@@ -55,8 +58,14 @@ export const StoreNotices = ( {
 				return;
 			}
 
-			// Get new notices from the API response.
-			const newNotices = extensions[ 'woocommerce-services' ].notices;
+			// Get new notices from the API response. The extension data is
+			// missing on WooCommerce versions where the Store API extension
+			// is not registered, and anything else on the response is outside
+			// our control, so treat everything but a list as "no notices":
+			// throwing here would take down the whole checkout fill.
+			const wcservicesData = extensions[ 'woocommerce-services' ];
+			const rawNotices     = wcservicesData && wcservicesData.notices;
+			const newNotices     = Array.isArray( rawNotices ) ? rawNotices : [];
 
 			if ( 0 === newNotices.length ) {
 				return;
@@ -75,5 +84,5 @@ export const StoreNotices = ( {
 		[ extensions ]
 	);
 
-	return <></>;
+	return null;
 };

client/components/store/notices/test/store-notices.js

@@ -0,0 +1,134 @@
+/** @format */
+
+/**
+ * External dependencies
+ */
+import React from 'react';
+import { mount } from 'enzyme';
+
+describe( 'StoreNotices', () => {
+	let createNotice;
+	let removeNotices;
+	let StoreNotices;
+	let existingNotices;
+
+	const usCart = { shippingAddress: { country: 'US', state: 'CA', postcode: '94105' } };
+	const caCart = { shippingAddress: { country: 'CA', state: 'ON', postcode: 'M5V 2T6' } };
+
+	const zipNotices = {
+		'woocommerce-services': {
+			notices: [ { type: 'error', message: 'ZIP could not be validated.' } ],
+		},
+	};
+
+	beforeEach( () => {
+		jest.resetModules();
+
+		createNotice = jest.fn();
+		removeNotices = jest.fn();
+		existingNotices = [];
+
+		global.window.wp = {
+			element: { useEffect: React.useEffect },
+			data: {
+				useDispatch: () => ( { createNotice, removeNotices } ),
+				useSelect: ( selector ) => selector( () => ( { getNotices: () => existingNotices } ) ),
+			},
+		};
+
+		( { StoreNotices } = require( '../store-notices' ) );
+	} );
+
+	afterEach( () => {
+		delete global.window.wp;
+	} );
+
+	it( 'creates notices from the extension data for US addresses', () => {
+		mount( <StoreNotices extensions={ zipNotices } cart={ usCart } /> );
+
+		// The id prefix is the contract the removal path relies on to find our own
+		// notices, so it is asserted rather than ignored.
+		expect( createNotice ).toHaveBeenCalledWith(
+			'error',
+			'ZIP could not be validated.',
+			expect.objectContaining( { id: 'wcservices-store-notices-0', context: 'wc/cart' } )
+		);
+	} );
+
+	it( 'does not create notices for non-US addresses', () => {
+		mount( <StoreNotices extensions={ zipNotices } cart={ caCart } /> );
+
+		expect( createNotice ).not.toHaveBeenCalled();
+	} );
+
+	it( 'removes only its own notices for US addresses', () => {
+		existingNotices = [
+			{ id: 'wcservices-store-notices-0' },
+			{ id: 'some-other-plugin-notice' },
+		];
+
+		mount( <StoreNotices extensions={ {} } cart={ usCart } /> );
+
+		expect( removeNotices ).toHaveBeenCalledWith( [ 'wcservices-store-notices-0' ], 'wc/cart' );
+	} );
+
+	it( 'does not remove notices for non-US addresses', () => {
+		existingNotices = [ { id: 'wcservices-store-notices-0' } ];
+
+		mount( <StoreNotices extensions={ {} } cart={ caCart } /> );
+
+		expect( removeNotices ).not.toHaveBeenCalled();
+	} );
+
+	it( 'creates notices again when new extension data arrives', () => {
+		const wrapper = mount( <StoreNotices extensions={ zipNotices } cart={ usCart } /> );
+
+		wrapper.setProps( {
+			extensions: {
+				'woocommerce-services': {
+					notices: [ { type: 'error', message: 'Address could not be validated.' } ],
+				},
+			},
+		} );
+
+		expect( createNotice ).toHaveBeenCalledTimes( 2 );
+		expect( createNotice ).toHaveBeenLastCalledWith(
+			'error',
+			'Address could not be validated.',
+			expect.objectContaining( { id: 'wcservices-store-notices-0', context: 'wc/cart' } )
+		);
+	} );
+
+	it( 'renders without crashing when the extension data is missing', () => {
+		// Old WooCommerce versions register the blocks integration but not the
+		// Store API extension, so extensions has no woocommerce-services key.
+		expect( () => {
+			mount( <StoreNotices extensions={ {} } cart={ usCart } /> );
+		} ).not.toThrow();
+
+		expect( createNotice ).not.toHaveBeenCalled();
+	} );
+
+	it( 'renders without crashing when the notices key is missing', () => {
+		expect( () => {
+			mount( <StoreNotices extensions={ { 'woocommerce-services': {} } } cart={ usCart } /> );
+		} ).not.toThrow();
+
+		expect( createNotice ).not.toHaveBeenCalled();
+	} );
+
+	it( 'renders without crashing when the notices data is not a list', () => {
+		// Anything on the Store API response is outside our control; a non-list must not
+		// reach forEach and take down the checkout fill.
+		expect( () => {
+			mount(
+				<StoreNotices
+					extensions={ { 'woocommerce-services': { notices: {} } } }
+					cart={ usCart }
+				/>
+			);
+		} ).not.toThrow();
+
+		expect( createNotice ).not.toHaveBeenCalled();
+	} );
+} );

client/store-notices.js

@@ -1,29 +1,31 @@
-/**
- * External dependencies
- */
-import React from 'react';
-
 /**
  * Internal dependencies
  */
 import { StoreNotices } from 'components/store/notices';
 
+// Every global read here is a script dependency: keep this list in sync with the
+// dependencies declared in WooCommerceBlocksIntegration::register_script(), which is
+// what guarantees these are loaded before this script runs.
 const { registerPlugin } = window.wp.plugins;
+const { createElement } = window.wp.element;
 const { ExperimentalOrderMeta } = window.wc.blocksCheckout;
 
 /**
  * Render function for the store notices.
  *
+ * Elements here must be created with the WordPress-provided React
+ * (window.wp.element), not the plugin's bundled React: this tree is rendered
+ * by the host React inside the Cart/Checkout blocks, and React 19 rejects
+ * elements created by an older React runtime. This is why the slot fill is
+ * built with createElement rather than the JSX used in the doc below.
+ *
  * @see https://github.com/woocommerce/woocommerce/blob/a7231863c014a95602f5932f702171465fa7bcf2/docs/cart-and-checkout-blocks/available-slot-fills.md?plain=1#L53
+ *   ExperimentalOrderMeta slot fill reference.
  *
- * @return {JSX.Element} The plugin content.
+ * @return {Object} The plugin content, as a host React element.
  */
 const render = () => {
-	return (
-		<ExperimentalOrderMeta>
-			<StoreNotices />
-		</ExperimentalOrderMeta>
-	);
+	return createElement( ExperimentalOrderMeta, null, createElement( StoreNotices ) );
 };
 
 registerPlugin( 'woocommerce-services-store-notices', {

client/test/store-notices.js

@@ -0,0 +1,65 @@
+/** @format */
+
+describe( 'store-notices entry', () => {
+	let registerPlugin;
+	let hostCreateElement;
+	const ExperimentalOrderMeta = () => null;
+
+	beforeEach( () => {
+		jest.resetModules();
+
+		registerPlugin = jest.fn();
+		hostCreateElement = jest.fn( ( type, props, ...children ) => ( {
+			type,
+			props,
+			children,
+			createdByHost: true,
+		} ) );
+
+		global.window.wp = {
+			plugins: { registerPlugin },
+			element: { createElement: hostCreateElement, useEffect: () => {} },
+			data: { useDispatch: () => ( {} ), useSelect: () => [] },
+		};
+		global.window.wc = { blocksCheckout: { ExperimentalOrderMeta } };
+	} );
+
+	afterEach( () => {
+		delete global.window.wp;
+		delete global.window.wc;
+	} );
+
+	it( 'registers the store notices plugin for the checkout scope', () => {
+		require( '../store-notices' );
+
+		expect( registerPlugin ).toHaveBeenCalledTimes( 1 );
+		expect( registerPlugin ).toHaveBeenCalledWith(
+			'woocommerce-services-store-notices',
+			expect.objectContaining( { scope: 'woocommerce-checkout' } )
+		);
+	} );
+
+	it( 'creates elements with the host React (window.wp.element), not a bundled React', () => {
+		// Share the entry's module registry so this is the same component instance
+		// the entry renders.
+		const { StoreNotices } = require( 'components/store/notices' );
+		require( '../store-notices' );
+
+		const { render } = registerPlugin.mock.calls[ 0 ][ 1 ];
+		const element = render();
+
+		// Every element handed to the host renderer must be created by the host
+		// createElement. An element created by the plugin's bundled React is
+		// rejected by React 19 ("A React Element from an older version of
+		// React was rendered").
+		expect( hostCreateElement ).toHaveBeenCalledTimes( 2 );
+		expect( element.createdByHost ).toBe( true );
+		expect( element.type ).toBe( ExperimentalOrderMeta );
+
+		// The child counts too: building only the outer element with the host React
+		// leaves the same React 19 rejection one level down.
+		const child = element.children[ 0 ];
+		expect( child.createdByHost ).toBe( true );
+		expect( child.type ).toBe( StoreNotices );
+	} );
+} );