WIP Fix for cases where a router is simultaneously frozen from 2 sources

Needs tests before merging

conductor/src/main/java/com/bluelinelabs/conductor/Controller.java

@@ -1364,20 +1364,21 @@ public abstract class Controller {
         changeHandler.onEnd();
     }
 
-    final void setDetachFrozen(boolean frozen) {
-        if (isDetachFrozen != frozen) {
-            isDetachFrozen = frozen;
+    final void onDetachFreezeUpdated(boolean frozen) {
+        if (isDetachFrozen == frozen) {
+            return;
+        }
 
-            for (ControllerHostedRouter router : childRouters) {
-                router.setDetachFrozen(frozen);
-            }
+        isDetachFrozen = frozen;
+        for (ControllerHostedRouter router : childRouters) {
+            router.onParentDetachFreezeUpdated(frozen);
+        }
 
-            if (!frozen && view != null && viewWasDetached) {
-                View aView = view;
-                detach(view, false, false);
-                if (view == null && aView.getParent() == router.container) {
-                    router.container.removeView(aView); // need to remove the view when this controller is a child controller
-                }
+        if (!frozen && view != null && viewWasDetached) {
+            View aView = view;
+            detach(view, false, false);
+            if (view == null && aView.getParent() == router.container) {
+                router.container.removeView(aView); // need to remove the view when this controller is a child controller
             }
         }
     }

conductor/src/main/java/com/bluelinelabs/conductor/ControllerHostedRouter.java

@@ -29,6 +29,7 @@ class ControllerHostedRouter extends Router {
 
     @IdRes private int hostId;
     private String tag;
+    private boolean isParentDetachFrozen;
     private boolean isDetachFrozen;
     private boolean boundToContainer;
 
@@ -89,13 +90,24 @@ class ControllerHostedRouter extends Router {
         container = null;
     }
 
+    final void onParentDetachFreezeUpdated(boolean frozen) {
+        isParentDetachFrozen = frozen;
+        for (RouterTransaction transaction : backstack) {
+            reportDetachFrozen(transaction.controller());
+        }
+    }
+
     final void setDetachFrozen(boolean frozen) {
         isDetachFrozen = frozen;
         for (RouterTransaction transaction : backstack) {
-            transaction.controller().setDetachFrozen(frozen);
+            reportDetachFrozen(transaction.controller());
         }
     }
 
+    private void reportDetachFrozen(@NonNull Controller controller) {
+        controller.onDetachFreezeUpdated(isDetachFrozen || isParentDetachFrozen);
+    }
+
     @Override
     void destroy(boolean popViews) {
         setDetachFrozen(false);
@@ -104,17 +116,17 @@ class ControllerHostedRouter extends Router {
 
     @Override
     protected void pushToBackstack(@NonNull RouterTransaction entry) {
-        if (isDetachFrozen) {
-            entry.controller().setDetachFrozen(true);
+        if (isDetachFrozen || isParentDetachFrozen) {
+            reportDetachFrozen(entry.controller());
         }
         super.pushToBackstack(entry);
     }
 
     @Override
     public void setBackstack(@NonNull List<RouterTransaction> newBackstack, @Nullable ControllerChangeHandler changeHandler) {
-        if (isDetachFrozen) {
+        if (isDetachFrozen || isParentDetachFrozen) {
             for (RouterTransaction transaction : newBackstack) {
-                transaction.controller().setDetachFrozen(true);
+                reportDetachFrozen(transaction.controller());
             }
         }
         super.setBackstack(newBackstack, changeHandler);