From 068394cd3c12d6c7be7a36ee89227c3ad546d6ed Mon Sep 17 00:00:00 2001
From: Dominic Farolino <dom@chromium.org>
Date: Wed, 13 Mar 2024 12:25:22 -0700
Subject: [PATCH] WPT: Script child removal does not trigger execution

Given the old Chromium change that introduced this behavior:
 - https://source.chromium.org/chromium/chromium/src/+/604e798ec6ee30f44d57a5c4a44ce3dab3a871ed

... the old discussion in:
 - https://github.com/whatwg/dom/pull/732#pullrequestreview-328249015
 - https://github.com/whatwg/html/pull/4354#issuecomment-476038918

... and the much newer discussion in:
 - https://github.com/whatwg/dom/pull/1261
 - https://github.com/whatwg/html/pull/10188

This CL upstreams an old test ensuring that removal of a child node
from a script node that has not "already started" [1], does not trigger
script execution. Only the *insertion* of child nodes (to a
non-already-started script node) should trigger that script's execution.

[1]: https://html.spec.whatwg.org/C#already-started

R=nrosenthal@chromium.org

Bug: 40150299
Change-Id: I750ccee0a2be834360c557042e975547c8ddd32c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5367238
Reviewed-by: Noam Rosenthal <nrosenthal@chromium.org>
Commit-Queue: Dominic Farolino <dom@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1272330}
---
 ...pt-does-not-run-on-child-removal.window.js | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 dom/nodes/insertion-removing-steps/script-does-not-run-on-child-removal.window.js

diff --git a/dom/nodes/insertion-removing-steps/script-does-not-run-on-child-removal.window.js b/dom/nodes/insertion-removing-steps/script-does-not-run-on-child-removal.window.js
new file mode 100644
index 00000000000000..ed5bfbaa60116c
--- /dev/null
+++ b/dom/nodes/insertion-removing-steps/script-does-not-run-on-child-removal.window.js
@@ -0,0 +1,33 @@
+// See:
+//  - https://github.com/whatwg/dom/issues/808
+//  - https://github.com/whatwg/dom/pull/1261
+//  - https://github.com/whatwg/html/pull/10188
+//  - https://source.chromium.org/chromium/chromium/src/+/604e798ec6ee30f44d57a5c4a44ce3dab3a871ed
+//  - https://github.com/whatwg/dom/pull/732#pullrequestreview-328249015
+//  - https://github.com/whatwg/html/pull/4354#issuecomment-476038918
+test(() => {
+  window.script_did_run = false;
+
+  const script = document.createElement('script');
+  // This prevents execution on insertion.
+  script.type = '0';
+  script.textContent = `script_did_run = true;`;
+  document.body.append(script);
+  assert_false(script_did_run,
+      'Appending script with invalid type does not trigger execution');
+
+  const div = document.createElement('div');
+  script.append(div);
+  assert_false(script_did_run,
+      'Appending a child to an invalid-type script does not trigger execution');
+
+  // This enables, but does not trigger, execution.
+  script.type = '';
+  assert_false(script_did_run,
+      'Unsetting script type does not trigger execution');
+
+  div.remove();
+  assert_false(script_did_run,
+      'Removing child from valid script that has not already run, does not ' +
+      'trigger execution');
+}, "Script execution is never triggered on child removals");