gh-14534: Prevent pinned tab from closing

src/zen/spaces/ZenSpaceManager.mjs

@@ -1081,6 +1081,12 @@ class nsZenWorkspaces {
       return null;
     }
 
+    // If the tab being closed is not selected, we don't need to select
+    // a new empty tab (as the active selection is already on a different tab).
+    if (!tab.selected) {
+      return null;
+    }
+
     let workspaceID = tab.getAttribute("zen-workspace-id");
     if (!workspaceID) {
       return null;

src/zen/tests/tabs/browser.toml

@@ -13,6 +13,8 @@ tags = [
   "vertical-tabs"
 ]
 
+["browser_issue_14534.js"]
+
 ["browser_tabs_close_recently.js"]
 
 ["browser_tabs_cycle_by_attribute.js"]

src/zen/tests/tabs/browser_issue_14534.js

@@ -0,0 +1,67 @@
+/* Any copyright is dedicated to the Public Domain.
+   https://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_setup(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [["zen.workspaces.open-new-tab-if-last-unpinned-tab-is-closed", true]],
+  });
+  registerCleanupFunction(async () => {
+    await SpecialPowers.popPrefEnv();
+  });
+});
+
+add_task(async function test_Close_Unpinned_While_Focused_On_Pinned() {
+  if (!gZenWorkspaces.workspaceEnabled) {
+    ok(true, "Workspaces disabled; the regression cannot occur. Skipping.");
+    return;
+  }
+
+  // Pin the currently selected tab
+  const pinnedTab = gBrowser.selectedTab;
+  gBrowser.pinTab(pinnedTab);
+  registerCleanupFunction(() => {
+    if (pinnedTab.pinned && !pinnedTab.closing) {
+      gBrowser.unpinTab(pinnedTab);
+    }
+  });
+
+  ok(pinnedTab.pinned, "Main tab should be pinned");
+  ok(pinnedTab.selected, "Main pinned tab should be selected");
+
+  // Open an unpinned tab
+  const unpinnedTab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "https://example.com"
+  );
+  registerCleanupFunction(async () => {
+    if (!unpinnedTab.closing) {
+      await BrowserTestUtils.removeTab(unpinnedTab);
+    }
+  });
+
+  // Re-select the pinned tab so we are focused on it
+  await BrowserTestUtils.switchTab(gBrowser, pinnedTab);
+  ok(pinnedTab.selected, "Pinned tab should be selected again");
+
+  // Spy on selectEmptyTab
+  let selectEmptyTabCalled = false;
+  const originalSelectEmptyTab = gZenWorkspaces.selectEmptyTab;
+  gZenWorkspaces.selectEmptyTab = function (...args) {
+    selectEmptyTabCalled = true;
+    return originalSelectEmptyTab.apply(this, args);
+  };
+  registerCleanupFunction(() => {
+    gZenWorkspaces.selectEmptyTab = originalSelectEmptyTab;
+  });
+
+  // Close the unpinned tab
+  await BrowserTestUtils.removeTab(unpinnedTab);
+
+  ok(
+    !selectEmptyTabCalled,
+    "Closing an unselected unpinned tab must not invoke selectEmptyTab"
+  );
+  ok(pinnedTab.selected, "The pinned tab should remain selected");
+});