From 4e1793e0020e2af4a3f9f5e6bc309079a2b67b0b Mon Sep 17 00:00:00 2001
From: Thibaut Gery <thibaut.gery@datadoghq.com>
Date: Thu, 16 Feb 2023 09:20:31 +0100
Subject: [PATCH] :bug:[RUMF-1493] Avoid infinite loop on `form > 
 input[name="host"]` element (#2017)

* [REPLAY] Fix freeze

Make sure to not count form element with child input as name host as a shadow root

* [REPLAY] Refactor unit tests for clarity

* [REPLAY] Update test labels for clarity

Co-authored-by: Bastien Caudan <1331991+bcaudan@users.noreply.github.com>

---------

Co-authored-by: Bastien Caudan <1331991+bcaudan@users.noreply.github.com>
---
 .../rum-core/src/browser/htmlDomUtils.spec.ts | 43 ++++++++++++++-----
 packages/rum-core/src/browser/htmlDomUtils.ts |  2 +-
 2 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/packages/rum-core/src/browser/htmlDomUtils.spec.ts b/packages/rum-core/src/browser/htmlDomUtils.spec.ts
index 4b7a309428..2fb5dbeb52 100644
--- a/packages/rum-core/src/browser/htmlDomUtils.spec.ts
+++ b/packages/rum-core/src/browser/htmlDomUtils.spec.ts
@@ -59,21 +59,42 @@ describe('isElementNode', () => {
 
 if (!isIE()) {
   describe('isShadowRoot', () => {
-    const parent = document.createElement('div')
-    parent.attachShadow({ mode: 'open' })
-    const parameters: Array<[Node, boolean]> = [
-      [parent.shadowRoot!, true],
-      [parent, false],
-      [document.body, false],
-      [document.createTextNode('hello'), false],
-      [document.createComment('hello'), false],
+    const notShadowDomNodes: Node[] = [
+      document,
+      document.head,
+      document.body,
+      document.createElement('div'),
+      document.createTextNode('hello'),
+      document.createComment('hello'),
     ]
 
-    parameters.forEach(([element, result]) => {
-      it(`should return ${String(result)} for "${String(element)}"`, () => {
-        expect(isNodeShadowRoot(element)).toBe(result)
+    notShadowDomNodes.forEach((element) => {
+      it(`should return false for "${String(element.nodeName)}"`, () => {
+        expect(isNodeShadowRoot(element)).toBe(false)
       })
     })
+
+    it('should return true for shadow root but not its host', () => {
+      const parent = document.createElement('div')
+      const shadowRoot = parent.attachShadow({ mode: 'open' })
+      expect(isNodeShadowRoot(parent)).toBe(false)
+      expect(isNodeShadowRoot(shadowRoot)).toBe(true)
+    })
+
+    it('should return false for a[href] despite it has a host property', () => {
+      const link = document.createElement('a')
+      link.setAttribute('href', 'http://localhost/some/path')
+      expect(link.host).toBeTruthy()
+      expect(isNodeShadowRoot(link)).toBe(false)
+    })
+
+    it('should return false for a form with an input[name="host"] despite it has a host property', () => {
+      const form = document.createElement('form')
+      const input = document.createElement('input')
+      input.setAttribute('name', 'host')
+      form.appendChild(input)
+      expect(isNodeShadowRoot(form)).toBe(false)
+    })
   })
 }
 
diff --git a/packages/rum-core/src/browser/htmlDomUtils.ts b/packages/rum-core/src/browser/htmlDomUtils.ts
index 0e05b69f5e..0cd2efe448 100644
--- a/packages/rum-core/src/browser/htmlDomUtils.ts
+++ b/packages/rum-core/src/browser/htmlDomUtils.ts
@@ -16,7 +16,7 @@ export function isNodeShadowHost(node: Node): node is Element & { shadowRoot: Sh
 
 export function isNodeShadowRoot(node: Node): node is ShadowRoot {
   const shadowRoot = node as ShadowRoot
-  return !!shadowRoot.host && isElementNode(shadowRoot.host)
+  return !!shadowRoot.host && shadowRoot.nodeType === Node.DOCUMENT_FRAGMENT_NODE && isElementNode(shadowRoot.host)
 }
 
 export function getChildNodes(node: Node) {