fix: create svg nested children with correct namespace

.changeset/long-shirts-thank.md

@@ -0,0 +1,5 @@
+---
+'@qwik.dev/core': patch
+---
+
+fix: create svg nested children with correct namespace

packages/qwik/src/core/client/vnode-diff.ts

@@ -722,7 +722,9 @@ export const vnode_diff = (
 
   function expectElement(jsx: JSXNodeInternal, elementName: string) {
     const isSameElementName =
-      vCurrent && vnode_isElementVNode(vCurrent) && elementName === vnode_getElementName(vCurrent);
+      vCurrent &&
+      vnode_isElementVNode(vCurrent) &&
+      elementName.toLowerCase() === vnode_getElementName(vCurrent);
     const jsxKey: string | null = jsx.key;
     let needsQDispatchEventPatch = false;
     const currentFile = getFileLocationFromJsx(jsx.dev);

packages/qwik/src/core/client/vnode-namespace.ts

@@ -10,6 +10,7 @@ import {
 } from './types';
 import {
   ensureElementVNode,
+  fastNamespaceURI,
   shouldIgnoreChildren,
   vnode_getDOMChildNodes,
   vnode_getDomParentVNode,
@@ -35,13 +36,15 @@ export const vnode_isDefaultNamespace = (vnode: ElementVNode): boolean => {
   return (flags & VNodeFlags.NAMESPACE_MASK) === 0;
 };
 
-export const vnode_getElementNamespaceFlags = (elementName: string) => {
-  if (isSvgElement(elementName)) {
-    return VNodeFlags.NS_svg;
-  } else if (isMathElement(elementName)) {
-    return VNodeFlags.NS_math;
-  } else {
-    return VNodeFlags.NS_html;
+export const vnode_getElementNamespaceFlags = (element: Element) => {
+  const namespace = fastNamespaceURI(element);
+  switch (namespace) {
+    case SVG_NS:
+      return VNodeFlags.NS_svg;
+    case MATH_NS:
+      return VNodeFlags.NS_math;
+    default:
+      return VNodeFlags.NS_html;
   }
 };
 

packages/qwik/src/core/client/vnode.ts

@@ -1192,9 +1192,10 @@ export const vnode_getElementName = (vnode: ElementVNode): string => {
   const elementVNode = ensureElementVNode(vnode);
   let elementName = elementVNode[ElementVNodeProps.elementName];
   if (elementName === undefined) {
-    elementName = elementVNode[ElementVNodeProps.elementName] =
-      elementVNode[ElementVNodeProps.element].nodeName.toLowerCase();
-    elementVNode[VNodeProps.flags] |= vnode_getElementNamespaceFlags(elementName);
+    const element = elementVNode[ElementVNodeProps.element];
+    const nodeName = fastNodeName(element)!.toLowerCase();
+    elementName = elementVNode[ElementVNodeProps.elementName] = nodeName;
+    elementVNode[VNodeProps.flags] |= vnode_getElementNamespaceFlags(element);
   }
   return elementName;
 };
@@ -1405,6 +1406,22 @@ const fastFirstChild = (node: Node | null): Node | null => {
   return node;
 };
 
+let _fastNamespaceURI: ((this: Element) => string | null) | null = null;
+export const fastNamespaceURI = (element: Element): string | null => {
+  if (!_fastNamespaceURI) {
+    _fastNamespaceURI = fastGetter<typeof _fastNamespaceURI>(element, 'namespaceURI')!;
+  }
+  return _fastNamespaceURI.call(element);
+};
+
+let _fastNodeName: ((this: Element) => string | null) | null = null;
+export const fastNodeName = (element: Element): string | null => {
+  if (!_fastNodeName) {
+    _fastNodeName = fastGetter<typeof _fastNodeName>(element, 'nodeName')!;
+  }
+  return _fastNodeName.call(element);
+};
+
 const fastGetter = <T>(prototype: any, name: string): T => {
   let getter: any;
   while (prototype && !(getter = Object.getOwnPropertyDescriptor(prototype, name)?.get)) {

packages/qwik/src/core/tests/render-namespace.spec.tsx

@@ -117,6 +117,66 @@ describe.each([
 
       await expect(container.document.body.querySelector('button')).toMatchDOM(<button></button>);
     });
+
+    it('should rerender svg nested children', async () => {
+      const SvgComp = component$((props: { show: boolean }) => {
+        return (
+          <svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg" key="0">
+            <defs>
+              {props.show && (
+                <linearGradient id="grad1" x1="0%" y1="0%" x2="100%" y2="0%">
+                  <stop offset="0%" style="stop-color:#ff0000;stop-opacity:1px" />
+                  <stop offset="100%" style="stop-color:#0000ff;stop-opacity:1px" />
+                </linearGradient>
+              )}
+            </defs>
+          </svg>
+        );
+      });
+      const Parent = component$(() => {
+        const show = useSignal(false);
+        return (
+          <button onClick$={() => (show.value = !show.value)}>
+            <SvgComp show={show.value} />
+          </button>
+        );
+      });
+      const { vNode, container } = await render(<Parent />, { debug });
+      expect(vNode).toMatchVDOM(
+        <Component>
+          <button>
+            <Component>
+              <svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg" key="0">
+                <defs></defs>
+              </svg>
+            </Component>
+          </button>
+        </Component>
+      );
+
+      await trigger(container.element, 'button', 'click');
+      expect(vNode).toMatchVDOM(
+        <Component>
+          <button>
+            <Component>
+              <svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg" key="0">
+                <defs>
+                  <linearGradient id="grad1" x1="0%" y1="0%" x2="100%" y2="0%">
+                    <stop offset="0%" style="stop-color:#ff0000;stop-opacity:1px" />
+                    <stop offset="100%" style="stop-color:#0000ff;stop-opacity:1px" />
+                  </linearGradient>
+                </defs>
+              </svg>
+            </Component>
+          </button>
+        </Component>
+      );
+
+      expect(
+        container.document.querySelector('svg')?.querySelector('linearGradient')?.namespaceURI
+      ).toEqual(SVG_NS);
+    });
+
     it('should rerender svg child elements', async () => {
       const SvgComp = component$((props: { child: JSXOutput }) => {
         return (