fix(parser): properly set initial inXML state based on root ns

packages/compiler-core/src/parser.ts

@@ -978,6 +978,10 @@ export function baseParse(input: string, options?: ParserOptions): RootNode {
         ? ParseMode.SFC
         : ParseMode.BASE
 
+  tokenizer.inXML =
+    currentOptions.ns === Namespaces.SVG ||
+    currentOptions.ns === Namespaces.MATH_ML
+
   const delimiters = options?.delimiters
   if (delimiters) {
     tokenizer.delimiterOpen = toCharCodes(delimiters[0])

packages/compiler-dom/__tests__/parse.spec.ts

@@ -481,5 +481,20 @@ describe('DOM parser', () => {
       expect(elementForieng.ns).toBe(Namespaces.SVG)
       expect(element.ns).toBe(Namespaces.HTML)
     })
+
+    test('correct XML handling with root ns', () => {
+      // when root ns is an XML namespace, there should be no special content
+      // treatment for <script>, <style>, <textarea> etc.
+      const ast = parse('<script><g/><g/></script>', {
+        ...parserOptions,
+        ns: Namespaces.SVG
+      })
+      const elementSvg = ast.children[0] as ElementNode
+      // should parse as nodes instead of text
+      expect(elementSvg.children).toMatchObject([
+        { type: NodeTypes.ELEMENT, tag: 'g' },
+        { type: NodeTypes.ELEMENT, tag: 'g' }
+      ])
+    })
   })
 })