Patch Zen window sync blank tabs

apps/zen.nix

@@ -1,6 +1,19 @@
 #./apps/zen.nix
-{ inputs, pkgs, lib, config, ... }:
-let
+{
+  inputs,
+  pkgs,
+  lib,
+  config,
+  ...
+}: let
+  # Zen keeps one live docshell for each logical tab and mirrors about:blank
+  # placeholders into the other synced windows. Upstream 1.23b changes the
+  # placeholder's ownership flags before confirming that the docshell swap
+  # succeeded (zen-browser/desktop#15702), so one failed swap can promote the
+  # blank placeholder and make later selections show "New Tab". Patch the
+  # shipped browser module until Zen includes an upstream fix.
+  windowSyncPatch = ../patches/zen-browser/window-sync-commit-ownership-after-swap.patch;
+
   # Autoconfig (mozilla.cfg) runs privileged JS in the parent process at
   # startup — the only scriptable way into chrome, since Gecko has no reload
   # for userChrome.css and Zen exposes no command for one.
@@ -97,33 +110,62 @@ let
       Components.utils.reportError("zen-theme: " + e);
     }
   '';
-in
-{
-  config = lib.mkIf (lib.elem config.networking.hostName [ "FredOS-Gaming" "FredOS-Macbook" ]) {
+in {
+  config = lib.mkIf (lib.elem config.networking.hostName ["FredOS-Gaming" "FredOS-Macbook"]) {
     environment.systemPackages = [
       ((inputs.zen-browser.packages.${pkgs.stdenv.hostPlatform.system}.default.override {
-        # Lands in defaults/pref/autoconfig.js, the only place this pref is
-        # read — setting it from mozilla.cfg is too late to unsandbox itself.
-        extraAutoConfig = ''
-          pref("general.config.sandbox_enabled", false);
-          pref("fred.zenTheme.autoconfig", true);
-        '';
-        extraPrefs = themeHotReload;
-      }).overrideAttrs (old: {
-        # wrapFirefox copies the executable it knows by name so that Gecko,
-        # which derives its application directory from the binary's *resolved*
-        # path, lands in the wrapper's tree. It knows this one as "zen-beta"
-        # (binaryName), but the binary actually exec'd is lib/zen-bin-*/zen —
-        # left behind as a symlink into the unwrapped package. So the app dir
-        # resolved to the unwrapped tree, which has no defaults/pref and no
-        # mozilla.cfg, and every pref and script above was silently skipped.
-        buildCommand = old.buildCommand + ''
-          for exe in "$out"/lib/zen*/zen "$out"/lib/zen*/zen-bin; do
-            cp --remove-destination "$(readlink -f "$exe")" "$exe"
-            chmod u+w "$exe"
-          done
-        '';
-      }))
+          # Lands in defaults/pref/autoconfig.js, the only place this pref is
+          # read — setting it from mozilla.cfg is too late to unsandbox itself.
+          extraAutoConfig = ''
+            pref("general.config.sandbox_enabled", false);
+            pref("fred.zenTheme.autoconfig", true);
+          '';
+          extraPrefs = themeHotReload;
+        }).overrideAttrs (old: {
+          # wrapFirefox copies the executable it knows by name so that Gecko,
+          # which derives its application directory from the binary's *resolved*
+          # path, lands in the wrapper's tree. It knows this one as "zen-beta"
+          # (binaryName), but the binary actually exec'd is lib/zen-bin-*/zen —
+          # left behind as a symlink into the unwrapped package. So the app dir
+          # resolved to the unwrapped tree, which has no defaults/pref and no
+          # mozilla.cfg, and every pref and script above was silently skipped.
+          buildCommand =
+            old.buildCommand
+            + ''
+              for exe in "$out"/lib/zen*/zen "$out"/lib/zen*/zen-bin; do
+                cp --remove-destination "$(readlink -f "$exe")" "$exe"
+                chmod u+w "$exe"
+              done
+
+              # Zen ships its privileged browser modules inside browser/omni.ja.
+              # Repack that archive with the local Window Sync fix; keeping this as
+              # a normal patch makes an upstream update fail loudly when the source
+              # changes instead of silently dropping the workaround.
+              for omni in "$out"/lib/zen*/browser/omni.ja; do
+                [ -f "$omni" ] || continue
+                cp "$(readlink -f "$omni")" "$omni.local"
+                mv -f "$omni.local" "$omni"
+
+                omniWork="$(mktemp -d)"
+                ${pkgs.unzip}/bin/unzip -q "$omni" -d "$omniWork" || {
+                  unzipStatus=$?
+                  # Mozilla's startup-optimized omnijar places its central
+                  # directory first. Info-ZIP extracts it correctly but exits 2
+                  # after warning about the nonstandard layout.
+                  [ "$unzipStatus" -eq 2 ] || exit "$unzipStatus"
+                }
+                ${pkgs.patch}/bin/patch --directory="$omniWork" -p1 \
+                  < ${windowSyncPatch}
+
+                rm "$omni"
+                (
+                  cd "$omniWork"
+                  ${pkgs.zip}/bin/zip -0 -X -q -r "$omni" .
+                )
+                rm -rf "$omniWork"
+              done
+            '';
+        }))
     ];
   };
 }