From c0b8f47a76e5a47e1dcf2c6e5a1a84f7b9efcfba Mon Sep 17 00:00:00 2001
From: Sam Atkins <sam@ladybird.org>
Date: Thu, 27 Nov 2025 15:57:18 +0000
Subject: [PATCH] LibWeb/HTML: Move connectedness check for script
 post_connection()

Corresponds to:
https://github.com/whatwg/html/commit/905384d140e5a5f093bb024114fd59aee40a30d8

Also import the test added along with that change.
---
 Libraries/LibWeb/HTML/HTMLScriptElement.cpp   | 29 ++++++------
 ...later-script-removed-by-earlier-script.txt |  7 +++
 ...ater-script-removed-by-earlier-script.html | 45 +++++++++++++++++++
 3 files changed, 67 insertions(+), 14 deletions(-)
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/dom/nodes/insertion-removing-steps/later-script-removed-by-earlier-script.txt
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/dom/nodes/insertion-removing-steps/later-script-removed-by-earlier-script.html

diff --git a/Libraries/LibWeb/HTML/HTMLScriptElement.cpp b/Libraries/LibWeb/HTML/HTMLScriptElement.cpp
index a085e91d25d..a09baa6d011 100644
--- a/Libraries/LibWeb/HTML/HTMLScriptElement.cpp
+++ b/Libraries/LibWeb/HTML/HTMLScriptElement.cpp
@@ -63,7 +63,7 @@ void HTMLScriptElement::attribute_changed(FlyString const& name, Optional<String
     } else if (name == HTML::AttributeNames::referrerpolicy) {
         m_referrer_policy = ReferrerPolicy::from_string(value.value_or(""_string)).value_or(ReferrerPolicy::ReferrerPolicy::EmptyString);
     } else if (name == HTML::AttributeNames::src) {
-        // https://html.spec.whatwg.org/multipage/scripting.html#script-processing-model:html-element-post-connection-steps-6
+        // https://html.spec.whatwg.org/multipage/scripting.html#script-processing-model:concept-element-attributes-change-ext
         // 1. If namespace is not null, then return.
         if (namespace_.has_value())
             return;
@@ -73,8 +73,9 @@ void HTMLScriptElement::attribute_changed(FlyString const& name, Optional<String
         if (!value.has_value())
             return;
 
-        // 2. If localName is src, then run the script HTML element post-connection steps, given element.
-        post_connection();
+        // 2. If localName is src and element is connected, then run the script HTML element post-connection steps, given element.
+        if (is_connected())
+            post_connection();
     } else if (name == HTML::AttributeNames::async) {
         // https://html.spec.whatwg.org/multipage/scripting.html#script-processing-model:script-force-async
         // When an async attribute is added to a script element el, the user agent must set el's force async to false.
@@ -631,27 +632,27 @@ void HTMLScriptElement::prepare_script()
     }
 }
 
-// https://html.spec.whatwg.org/multipage/scripting.html#script-processing-model:html-element-post-connection-steps-4
+// https://html.spec.whatwg.org/multipage/scripting.html#script-processing-model:children-changed-steps
 void HTMLScriptElement::children_changed(ChildrenChangedMetadata const* metadata)
 {
     Base::children_changed(metadata);
 
-    // 1. Run the script HTML element post-connection steps, given the script element.
-    post_connection();
-}
-
-// https://html.spec.whatwg.org/multipage/scripting.html#script-processing-model:prepare-the-script-element-5
-void HTMLScriptElement::post_connection()
-{
-    // 1. If insertedNode is not connected, then return.
+    // 1. If the script element is not connected, then return.
     if (!is_connected())
         return;
 
-    // 2. If insertedNode is parser-inserted, then return.
+    // 2. Run the script HTML element post-connection steps, given the script element.
+    post_connection();
+}
+
+// https://html.spec.whatwg.org/multipage/scripting.html#script-processing-model:html-element-post-connection-steps
+void HTMLScriptElement::post_connection()
+{
+    // 1. If insertedNode is parser-inserted, then return.
     if (is_parser_inserted())
         return;
 
-    // 3. Prepare the script element given insertedNode.
+    // 2. Prepare the script element given insertedNode.
     prepare_script();
 }
 
diff --git a/Tests/LibWeb/Text/expected/wpt-import/dom/nodes/insertion-removing-steps/later-script-removed-by-earlier-script.txt b/Tests/LibWeb/Text/expected/wpt-import/dom/nodes/insertion-removing-steps/later-script-removed-by-earlier-script.txt
new file mode 100644
index 00000000000..51527a24aca
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/dom/nodes/insertion-removing-steps/later-script-removed-by-earlier-script.txt
@@ -0,0 +1,7 @@
+Harness status: OK
+
+Found 2 tests
+
+2 Pass
+Pass	A later-inserted script removed by an earlier-inserted script in the same document fragment should not run
+Pass	A later-inserted script removed by an earlier-inserted script in the same append() call should not run
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/dom/nodes/insertion-removing-steps/later-script-removed-by-earlier-script.html b/Tests/LibWeb/Text/input/wpt-import/dom/nodes/insertion-removing-steps/later-script-removed-by-earlier-script.html
new file mode 100644
index 00000000000..b648a0074c0
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/dom/nodes/insertion-removing-steps/later-script-removed-by-earlier-script.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>A later-inserted script removed by an earlier-inserted script does not run</title>
+<script src=../../../resources/testharness.js></script>
+<script src=../../../resources/testharnessreport.js></script>
+<body>
+<script>
+
+test(t => {
+  const fragment = document.createDocumentFragment();
+  // Global so they can be more easily accessed by the inner script blocks.
+  window.script1 = fragment.appendChild(document.createElement("script"));
+  window.script2 = fragment.appendChild(document.createElement("script"));
+
+  window.script2Run = false;
+  t.add_cleanup(() => { window.script2Run = false; });
+  script1.textContent = `
+    assert_true(script2.isConnected, 'script2 is connected when script2 runs');
+    script2.remove();
+  `;
+  script2.textContent = "window.script2Run = true;";
+
+  document.body.append(fragment);
+  assert_false(window.script2Run, "script2 did not run");
+}, "A later-inserted script removed by an earlier-inserted script in the " +
+   "same document fragment should not run");
+
+test(t => {
+  window.script1 = document.createElement("script");
+  window.script2 = document.createElement("script");
+
+  window.script2Run = false;
+  t.add_cleanup(() => { window.script2Run = false; });
+  script1.textContent = `
+    assert_true(script2.isConnected, 'script2 is connected when script2 runs');
+    script2.remove();
+  `;
+  script2.textContent = "window.script2Run = true;";
+
+  document.body.append(script1, script2);
+  assert_false(window.script2Run, "script2 did not run");
+}, "A later-inserted script removed by an earlier-inserted script in the " +
+   "same append() call should not run");
+</script>
+</body>