From 66c1f8a89891b93a25b0338d51281ba1bf3e259a Mon Sep 17 00:00:00 2001
From: MinhHaDuong <minh.haduong@gmail.com>
Date: Tue, 22 Sep 2026 11:37:07 +0200
Subject: [PATCH] Keep pending removals live during asynchronous teardown

---
 app/scripts/fetch_xulrunner                   | 22 +++++++------------
 .../addon-list-pending-uninstall.test.mjs     | 18 ++++++++++++++-
 2 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/app/scripts/fetch_xulrunner b/app/scripts/fetch_xulrunner
index fbc339d199..ebfb43de85 100755
--- a/app/scripts/fetch_xulrunner
+++ b/app/scripts/fetch_xulrunner
@@ -464,29 +464,23 @@ function modify_omni {
 	# The Add-ons window can retain the old add-on wrapper after a replacement.
 	# Finalizing that wrapper's pending uninstall would remove the new copy by ID.
 	replace_line '  disconnectedCallback\(\) \{' '  async disconnectedCallback() {' $file
-	remove_line '    this.pendingUninstallAddons.clear\(\);' $file
 	replace_line '    for \(const addon of this.pendingUninstallAddons\) \{' \
-		'    const pendingUninstalls = [...this.pendingUninstallAddons];
-    this.pendingUninstallAddons.clear();
-    for (let i = 0; i < pendingUninstalls.length; i++) {
-      const addon = pendingUninstalls[i];' $file
+		'    for (const addon of [...this.pendingUninstallAddons]) {' $file
 	replace_line '      if \(isPending\(addon, "uninstall"\)\) \{' \
 		'      let current;
       try {
         current = await AddonManager.getAddonByID(addon.id);
       } catch (error) {
         console.error(error);
-        this.pendingUninstallAddons.add(addon);
-      }
-      if (this.isConnected) {
-        for (const pending of pendingUninstalls.slice(i)) {
-          if (isPending(pending, "uninstall")) {
-            this.pendingUninstallAddons.add(pending);
-          }
-        }
         return;
       }
-      if (current === addon && isPending(current, "uninstall")) {' $file
+      if (this.isConnected) {
+        return;
+      }
+      if (this.pendingUninstallAddons.has(addon) && current === addon && isPending(current, "uninstall")) {' $file
+	replace_line '        addon.uninstall\(\);' \
+		'        addon.uninstall();
+        this.pendingUninstallAddons.delete(addon);' $file
 	replace_line '  onInstalled\(addon\) \{' '  onInstalled(addon) {
     if (!isPending(addon, "uninstall")) {
       for (const pending of this.pendingUninstallAddons) {
diff --git a/app/scripts/tests/addon-list-pending-uninstall.test.mjs b/app/scripts/tests/addon-list-pending-uninstall.test.mjs
index 8637d3e8ba..5241afc889 100644
--- a/app/scripts/tests/addon-list-pending-uninstall.test.mjs
+++ b/app/scripts/tests/addon-list-pending-uninstall.test.mjs
@@ -76,7 +76,7 @@ test('a reconnect during lookup leaves newly queued removals intact', async () =
 	const list = createList(() => new Promise(resolve => { resolveLookup = resolve; }));
 	list.pendingUninstallAddons.add(old);
 	const teardown = list.disconnectedCallback();
-	assert.equal(list.pendingUninstallAddons.size, 0);
+	assert.equal(list.pendingUninstallAddons.has(old), true);
 	list.isConnected = true;
 	list.pendingUninstallAddons.add(fresh);
 	resolveLookup(old);
@@ -85,6 +85,22 @@ test('a reconnect during lookup leaves newly queued removals intact', async () =
 	assert.equal(list.pendingUninstallAddons.has(fresh), true);
 });
 
+test('install notification during lookup removes the stale entry before reconnect', async () => {
+	let resolveLookup;
+	let uninstalls = 0;
+	const old = { id: 'plugin@test', pendingUninstall: true, uninstall: () => uninstalls++ };
+	const replacement = { id: old.id, pendingUninstall: false };
+	const list = createList(() => new Promise(resolve => { resolveLookup = resolve; }));
+	list.pendingUninstallAddons.add(old);
+	const teardown = list.disconnectedCallback();
+	list.onInstalled(replacement);
+	list.isConnected = true;
+	resolveLookup(replacement);
+	await teardown;
+	assert.equal(uninstalls, 0);
+	assert.equal(list.pendingUninstallAddons.has(old), false);
+});
+
 test('a reconnect mid-loop preserves the unprocessed pending removal', async () => {
 	let resolveSecond;
 	let firstUninstalls = 0;