🐛 Restore parent sync state when undoing child structure edits

Add, remove and move inverses restore the copy parent's remote-synced
flag with its touched groups. Swapping a child clears that flag during
delete; undo must restore the original parent state (F157).

Swap and add/remove regressions fail before the change. The focused swap
suite passes 49 tests and 191 assertions; common lint and format pass.
Benchmark ratios: mains 0.49/0.57/0.62; levels 0.53; chain 0.57; library
0.69; many shapes 0.62; switch 0.62, no regression flags.

AI-assisted-by: GPT-6

.serena/memories/common/changes-architecture.md

@@ -36,4 +36,9 @@ For component touched semantics and sync groups, read `mem:common/component-data
 
 ## Inspection
 
-To inspect what a UI action emitted, use `mem:frontend/cljs-repl` with the snippets in `mem:common/component-debugging-recipes` rather than adding temporary source instrumentation.
+To inspect what a UI action emitted, use `mem:frontend/cljs-repl` with the snippets in `mem:common/component-debugging-recipes` rather than adding temporary source instrumentation.
+
+- Structural add/remove and change-parent inverses restore the copy parent's
+  `:remote-synced` as well as `:touched`. Removing or adding a child clears
+  the former even when touched groups do not change; restoring only the
+  groups loses prior state on undo (F157).

common/src/app/common/files/changes_builder.cljc

@@ -458,6 +458,15 @@
 
 ;; Shape tree changes
 
+(defn- restore-parent-state-change
+  [page-id parent]
+  {:type :mod-obj
+   :page-id page-id
+   :id (:id parent)
+   :operations (cond-> [{:type :set-touched :touched (:touched parent)}]
+                 (:remote-synced parent)
+                 (conj {:type :set-remote-synced :remote-synced true}))})
+
 (defn add-object
   ([changes obj]
    (add-object changes obj nil))
@@ -489,11 +498,7 @@
           :ignore-touched true}
 
          restore-touched-change
-         {:type :mod-obj
-          :page-id (::page-id (meta changes))
-          :id (:id parent)
-          :operations [{:type :set-touched
-                        :touched (:touched parent)}]}]
+         (restore-parent-state-change (::page-id (meta changes)) parent)]
 
      (-> changes
          (update :redo-changes conj add-change)
@@ -552,11 +557,7 @@
                      (assoc :allow-altering-copies true)))))
 
          restore-touched-change
-         {:type :mod-obj
-          :page-id (::page-id (meta changes))
-          :id (:id parent)
-          :operations [{:type :set-touched
-                        :touched (:touched parent)}]}]
+         (restore-parent-state-change (::page-id (meta changes)) parent)]
 
      (-> changes
          (update :redo-changes conj set-parent-change)
@@ -723,6 +724,13 @@
     (-> changes
         (update :redo-changes #(reduce add-redo-change % ids))
         (update :undo-changes #(as-> % $
+                                 (reduce (fn [undo parent-id]
+                                           (let [parent (get objects parent-id)]
+                                             (cond-> undo
+                                               (and (not ignore-touched) (:shape-ref parent)
+                                                    (:remote-synced parent))
+                                               (conj (restore-parent-state-change page-id parent)))))
+                                         $ (distinct (keep (fn [id] (:parent-id (get objects id))) ids)))
                                  (reduce add-undo-change-parent $ ids)
                                  (reduce add-undo-change-shape $ ids))))))
 

common/test/common_tests/logic/swap_group_test.cljc

@@ -821,3 +821,30 @@
         undone (r/step moved (n/undo))]
     (t/is (nil? (:touched head)))
     (t/is (= (thn/normalize-file file) (thn/normalize-file (tm/file undone))))))
+
+(t/deftest swapping-a-child-restores-its-parents-remote-sync-flag-on-undo
+  (let [initial (tm/make-situation (ths/update-shape (setup-sized) :copy :remote-synced true))
+        swapped (-> initial (r/step (n/swap-shape :copy-star :heart)) r/settle)
+        undone (r/step swapped (n/undo))]
+    (t/is (:remote-synced (tm/resolve-shape initial :copy)))
+    (t/is (not (:remote-synced (tm/resolve-shape swapped :copy))))
+    (t/is (:remote-synced (tm/resolve-shape undone :copy)))
+    (t/is (= (thn/normalize-file (tm/file initial))
+             (thn/normalize-file (tm/file undone))))))
+
+(t/deftest structural-child-changes-restore-the-parents-remote-sync-state
+  (doseq [operation [:add :remove]]
+    (let [file (ths/update-shape (setup-sized) :copy-star :remote-synced true)
+          page (thf/current-page file)
+          parent (ths/get-shape file :copy-star)
+          changes (-> (pcb/empty-changes nil (:id page))
+                      (pcb/with-objects (:objects page)))
+          changes (case operation
+                    :add (pcb/add-object changes (ths/sample-shape :added
+                                                                   :parent-id (:id parent)
+                                                                   :frame-id (:id parent)))
+                    :remove (pcb/remove-objects changes [(first (:shapes parent))]))
+          changed (thf/apply-changes file changes :validate? false)
+          undone (thf/apply-undo-changes changed changes)]
+      (t/is (not (:remote-synced (ths/get-shape changed :copy-star))) (name operation))
+      (t/is (= (thn/normalize-file file) (thn/normalize-file undone)) (name operation)))))