Refactor ZenTabUnloader and ZenWorkspaces to improve tab unloading logic and enhance session restoration handling

src/browser/base/content/browser-commands-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/base/content/browser-commands.js b/browser/base/content/browser-commands.js
-index 352de44dda36e3f6672eb353f42978ede0cd2681..66d1616da17df3430cec0994a346f0f446944f1a 100644
+index 352de44dda36e3f6672eb353f42978ede0cd2681..0fde717eaf755526ec65b676c43bd34c6a675934 100644
 --- a/browser/base/content/browser-commands.js
 +++ b/browser/base/content/browser-commands.js
 @@ -318,6 +318,10 @@ var BrowserCommands = {
@@ -13,7 +13,18 @@ index 352de44dda36e3f6672eb353f42978ede0cd2681..66d1616da17df3430cec0994a346f0f4
      // A notification intended to be useful for modular peformance tracking
      // starting as close as is reasonably possible to the time when the user
      // expressed the intent to open a new tab.  Since there are a lot of
-@@ -407,8 +411,8 @@ var BrowserCommands = {
+@@ -400,6 +404,10 @@ var BrowserCommands = {
+       return;
+     }
+ 
++    if (gBrowser.selectedTab.hasAttribute("zen-empty-tab")) {
++      return;
++    }
++
+     // Keyboard shortcuts that would close a tab that is pinned select the first
+     // unpinned tab instead.
+     if (
+@@ -407,8 +415,8 @@ var BrowserCommands = {
        (event.ctrlKey || event.metaKey || event.altKey) &&
        gBrowser.selectedTab.pinned
      ) {

src/browser/base/zen-components/ZenTabUnloader.mjs

@@ -225,6 +225,10 @@
 
     unloadTab() {
       const tabs = TabContextMenu.contextTab.multiselected ? gBrowser.selectedTabs : [TabContextMenu.contextTab];
+      this.explicitUnloadTabs(tabs);
+    }
+
+    explicitUnloadTabs(tabs) {
       for (let i = 0; i < tabs.length; i++) {
         if (this.canUnloadTab(tabs[i], Date.now(), this.intervalUnloader.excludedUrls, true)) {
           this.unload(tabs[i]);
@@ -263,7 +267,7 @@
         (tab.pictureinpicture && !ignoreTimestamp) ||
         (tab.soundPlaying && !ignoreTimestamp) ||
         (tab.zenIgnoreUnload && !ignoreTimestamp) ||
-        excludedUrls.some((url) => url.test(tab.linkedBrowser.currentURI.spec))
+        excludedUrls.some((url) => url.test(tab.linkedBrowser?.currentURI.spec))
       ) {
         return false;
       }

src/browser/base/zen-components/ZenWorkspaces.mjs

@@ -38,7 +38,7 @@ var ZenWorkspaces = new (class extends ZenMultiWindowFeature {
   `;
 
   async waitForPromises() {
-    await Promise.all([this.promiseDBInitialized, this.promisePinnedInitialized]);
+    await Promise.all([this.promiseDBInitialized, this.promisePinnedInitialized, SessionStore.promiseAllWindowsRestored]);
   }
 
   async init() {
@@ -599,9 +599,16 @@ var ZenWorkspaces = new (class extends ZenMultiWindowFeature {
     let showed = false;
     if (currentTab.pinned) {
       this.selectEmptyTab();
+      gZenTabUnloader.explicitUnloadTabs([currentTab]);
       showed = true;
     } else {
-      if (currentTab.isEmpty) {
+      const currentTabURL = currentTab.linkedBrowser?.currentURI?.spec;
+      // Check for empty tab being restored
+      if (
+        (currentTab.isEmpty &&
+          (currentTab.getAttribute('image') === gPageIcons[currentTabURL] || !currentTab.hasAttribute('image'))) ||
+        currentTab.hasAttribute('zen-empty-tab')
+      ) {
         this.selectEmptyTab();
         gBrowser.removeTab(currentTab);
         showed = true;

src/browser/components/sessionstore/SessionStore-sys-mjs.patch

@@ -1,20 +1,8 @@
 diff --git a/browser/components/sessionstore/SessionStore.sys.mjs b/browser/components/sessionstore/SessionStore.sys.mjs
-index 334c041c1748564094c6a177bb24f146791d96d8..c8f4ad6eeab4bf1ede6f23814d370d839ed83f76 100644
+index 334c041c1748564094c6a177bb24f146791d96d8..e301cc1df604e4a23fcf260d5952736f5b791803 100644
 --- a/browser/components/sessionstore/SessionStore.sys.mjs
 +++ b/browser/components/sessionstore/SessionStore.sys.mjs
-@@ -2174,9 +2174,10 @@ var SessionStoreInternal = {
+@@ -3848,6 +3848,7 @@ var SessionStoreInternal = {
-           TelemetryStopwatch.finish(
-             "FX_SESSION_RESTORE_STARTUP_ONLOAD_INITIAL_WINDOW_MS"
-           );
--
-+          aWindow.ZenWorkspaces.delayedStartup().then(() => {
-           // Let everyone know we're done.
-           this._deferredInitialized.resolve();
-+          });
-         }
-       })
-       .catch(ex => {
-@@ -3848,6 +3849,7 @@ var SessionStoreInternal = {
          aWindow.gBrowser.selectedTab = newTab;
        }
  
@@ -22,7 +10,7 @@ index 334c041c1748564094c6a177bb24f146791d96d8..c8f4ad6eeab4bf1ede6f23814d370d83
        // Restore the state into the new tab.
        this.restoreTab(newTab, tabState, {
          restoreImmediately: aRestoreImmediately,
-@@ -5315,14 +5317,14 @@ var SessionStoreInternal = {
+@@ -5315,14 +5316,14 @@ var SessionStoreInternal = {
      }
  
      let tabbrowser = aWindow.gBrowser;

src/browser/components/sessionstore/TabState-sys-mjs.patch

@@ -1,8 +1,8 @@
 diff --git a/browser/components/sessionstore/TabState.sys.mjs b/browser/components/sessionstore/TabState.sys.mjs
-index 8f7ed557e6aa61e7e16ed4a8d785ad5fe651b3d8..83bf443ca158c07e05075777da02b7f228d83dff 100644
+index 8f7ed557e6aa61e7e16ed4a8d785ad5fe651b3d8..05dbb00375523819163bcd225074117ef02b8b37 100644
 --- a/browser/components/sessionstore/TabState.sys.mjs
 +++ b/browser/components/sessionstore/TabState.sys.mjs
-@@ -84,6 +84,13 @@ class _TabState {
+@@ -84,6 +84,14 @@ class _TabState {
        tabData.groupId = tab.group.id;
      }
  
@@ -12,6 +12,7 @@ index 8f7ed557e6aa61e7e16ed4a8d785ad5fe651b3d8..83bf443ca158c07e05075777da02b7f2
 +    tabData.zenDefaultUserContextId = tab.getAttribute("zenDefaultUserContextId");
 +    tabData.zenPinnedEntry = tab.getAttribute("zen-pinned-entry");
 +    tabData.zenPinnedIcon = tab.getAttribute("zen-pinned-icon");
++    tabData.zenIsEmpty = tab.hasAttribute("zen-empty-tab");
 +
      tabData.searchMode = tab.ownerGlobal.gURLBar.getSearchMode(browser, true);
  

src/browser/components/tabbrowser/content/tabbrowser-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/components/tabbrowser/content/tabbrowser.js b/browser/components/tabbrowser/content/tabbrowser.js
-index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43a2c676bd 100644
+index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..3523627188284f0af992d29bb0863f8ae20d5094 100644
 --- a/browser/components/tabbrowser/content/tabbrowser.js
 +++ b/browser/components/tabbrowser/content/tabbrowser.js
 @@ -406,11 +406,52 @@
@@ -187,13 +187,16 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        // Additionally send pinned tab events
        if (pinned) {
          this._notifyPinnedStatus(t);
-@@ -3403,6 +3469,21 @@
+@@ -3403,6 +3469,24 @@
          ) {
            tabWasReused = true;
            tab = this.selectedTab;
 +          if (tabData.zenWorkspace) {
 +            tab.setAttribute("zen-workspace-id", tabData.zenWorkspace);
 +          }
++          if (tabData.zenIsEmpty) {
++            tab.setAttribute("zen-empty-tab", "true");
++          }
 +          if (tabData.zenPinnedId) {
 +            tab.setAttribute("zen-pin-id", tabData.zenPinnedId);
 +          }
@@ -209,7 +212,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
            if (!tabData.pinned) {
              this.unpinTab(tab);
            } else {
-@@ -3416,6 +3497,7 @@
+@@ -3416,6 +3500,7 @@
              restoreTabsLazily && !select && !tabData.pinned;
  
            let url = "about:blank";
@@ -217,7 +220,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
            if (tabData.entries?.length) {
              let activeIndex = (tabData.index || tabData.entries.length) - 1;
              // Ensure the index is in bounds.
-@@ -3451,7 +3533,21 @@
+@@ -3451,7 +3536,24 @@
              skipLoad: true,
              preferredRemoteType,
            });
@@ -228,6 +231,9 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
 +          if (tabData.zenPinnedId) {
 +            tab.setAttribute("zen-pin-id", tabData.zenPinnedId);
 +          }
++          if (tabData.zenIsEmpty) {
++            tab.setAttribute("zen-empty-tab", "true");
++          }
 +          if (tabData.zenEssential) {
 +            tab.setAttribute("zen-essential", "true");
 +          }
@@ -240,7 +246,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
            if (select) {
              tabToSelect = tab;
            }
-@@ -3464,8 +3560,8 @@
+@@ -3464,8 +3566,8 @@
            // inserted in the DOM. If the tab is not yet in the DOM,
            // just insert it in the right place from the start.
            if (!tab.parentNode) {
@@ -251,7 +257,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
              tab.toggleAttribute("pinned", true);
              this.tabContainer._invalidateCachedTabs();
              // Then ensure all the tab open/pinning information is sent.
-@@ -3729,7 +3825,7 @@
+@@ -3729,7 +3831,7 @@
        // Ensure we have an index if one was not provided.
        if (typeof index != "number") {
          // Move the new tab after another tab if needed, to the end otherwise.
@@ -260,7 +266,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
          if (
            !bulkOrderedOpen &&
            ((openerTab &&
-@@ -3780,7 +3876,7 @@
+@@ -3780,7 +3882,7 @@
        }
  
        /** @type {MozTabbrowserTab|undefined} */
@@ -269,7 +275,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        this.tabContainer._invalidateCachedTabs();
  
        if (tabGroup) {
-@@ -4095,6 +4191,9 @@
+@@ -4095,6 +4197,9 @@
          return;
        }
  
@@ -279,7 +285,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        this.removeTabs(selectedTabs);
      }
  
-@@ -4427,6 +4526,7 @@
+@@ -4427,6 +4532,7 @@
          skipSessionStore,
        } = {}
      ) {
@@ -287,7 +293,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        if (UserInteraction.running("browser.tabs.opening", window)) {
          UserInteraction.finish("browser.tabs.opening", window);
        }
-@@ -4443,6 +4543,12 @@
+@@ -4443,6 +4549,12 @@
          TelemetryStopwatch.start("FX_TAB_CLOSE_TIME_NO_ANIM_MS", aTab);
        }
  
@@ -300,7 +306,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        // Handle requests for synchronously removing an already
        // asynchronously closing tab.
        if (!animate && aTab.closing) {
-@@ -4457,7 +4563,9 @@
+@@ -4457,7 +4569,9 @@
        // frame created for it (for example, by updating the visually selected
        // state).
        let tabWidth = window.windowUtils.getBoundsWithoutFlushing(aTab).width;
@@ -311,7 +317,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        if (
          !this._beginRemoveTab(aTab, {
            closeWindowFastpath: true,
-@@ -4471,7 +4579,6 @@
+@@ -4471,7 +4585,6 @@
          TelemetryStopwatch.cancel("FX_TAB_CLOSE_TIME_NO_ANIM_MS", aTab);
          return;
        }
@@ -319,16 +325,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        let lockTabSizing =
          !this.tabContainer.verticalMode &&
          !aTab.pinned &&
-@@ -4550,7 +4657,7 @@
+@@ -4610,14 +4723,14 @@
-         skipSessionStore = false,
-       } = {}
-     ) {
--      if (aTab.closing || this._windowIsClosing) {
-+      if (aTab.closing || this._windowIsClosing || aTab.hasAttribute("zen-empty-tab")) {
-         return false;
-       }
- 
-@@ -4610,14 +4717,14 @@
          !!this.tabsInCollapsedTabGroups.length;
        if (
          aTab.visible &&
@@ -345,7 +342,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
  
          if (closeWindow) {
            // We've already called beforeunload on all the relevant tabs if we get here,
-@@ -4681,9 +4788,7 @@
+@@ -4681,9 +4794,7 @@
        aTab._mouseleave();
  
        if (newTab) {
@@ -356,7 +353,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        } else {
          TabBarVisibility.update();
        }
-@@ -4812,6 +4917,8 @@
+@@ -4812,6 +4923,8 @@
          this.tabs[i]._tPos = i;
        }
  
@@ -365,7 +362,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        if (!this._windowIsClosing) {
          if (wasPinned) {
            this.tabContainer._positionPinnedTabs();
-@@ -5025,7 +5132,7 @@
+@@ -5025,7 +5138,7 @@
          !excludeTabs.has(aTab.owner) &&
          Services.prefs.getBoolPref("browser.tabs.selectOwnerOnClose")
        ) {
@@ -374,7 +371,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        }
  
        // Try to find a remaining tab that comes after the given tab
-@@ -5047,7 +5154,7 @@
+@@ -5047,7 +5160,7 @@
        }
  
        if (tab) {
@@ -383,7 +380,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        }
  
        // If no qualifying visible tab was found, see if there is a tab in
-@@ -5465,10 +5572,10 @@
+@@ -5465,10 +5578,10 @@
        SessionStore.deleteCustomTabValue(aTab, "hiddenBy");
      }
  
@@ -396,7 +393,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
          aTab.selected ||
          aTab.closing ||
          // Tabs that are sharing the screen, microphone or camera cannot be hidden.
-@@ -5706,9 +5813,9 @@
+@@ -5706,9 +5819,9 @@
  
        // Don't allow mixing pinned and unpinned tabs.
        if (aTab.pinned) {
@@ -408,7 +405,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        }
        if (aTab._tPos == aIndex) {
          return;
-@@ -5717,7 +5824,7 @@
+@@ -5717,7 +5830,7 @@
        this._lastRelatedTabMap = new WeakMap();
  
        this._handleTabMove(aTab, () => {
@@ -417,7 +414,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
          if (forceStandaloneTab && neighbor.group) {
            neighbor = neighbor.group;
          }
-@@ -5802,7 +5909,7 @@
+@@ -5802,7 +5915,7 @@
          createLazyBrowser,
        };
  
@@ -426,7 +423,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
        if (aIndex < numPinned || (aTab.pinned && aIndex == numPinned)) {
          params.pinned = true;
        }
-@@ -7443,6 +7550,7 @@
+@@ -7443,6 +7556,7 @@
              aWebProgress.isTopLevel
            ) {
              this.mTab.setAttribute("busy", "true");
@@ -434,7 +431,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
              gBrowser._tabAttrModified(this.mTab, ["busy"]);
              this.mTab._notselectedsinceload = !this.mTab.selected;
              gBrowser.syncThrobberAnimations(this.mTab);
-@@ -8411,7 +8519,7 @@ var TabContextMenu = {
+@@ -8411,7 +8525,7 @@ var TabContextMenu = {
      );
      contextUnpinSelectedTabs.hidden =
        !this.contextTab.pinned || !multiselectionContext;
@@ -443,7 +440,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
      // Move Tab items
      let contextMoveTabOptions = document.getElementById(
        "context_moveTabOptions"
-@@ -8444,7 +8552,7 @@ var TabContextMenu = {
+@@ -8444,7 +8558,7 @@ var TabContextMenu = {
      let contextMoveTabToStart = document.getElementById("context_moveToStart");
      let isFirstTab =
        tabsToMove[0] == visibleTabs[0] ||
@@ -452,7 +449,7 @@ index ff90a70bdad6c94ec4b90027ff102972d0eb28e5..5ae4351d7438c0e03c0a24551c910d43
      contextMoveTabToStart.disabled = isFirstTab && allSelectedTabsAdjacent;
  
      document.getElementById("context_openTabInWindow").disabled =
-@@ -8677,6 +8785,7 @@ var TabContextMenu = {
+@@ -8677,6 +8791,7 @@ var TabContextMenu = {
      if (this.contextTab.multiselected) {
        gBrowser.removeMultiSelectedTabs();
      } else {