diff options
| -rw-r--r-- | server/src/com/vaadin/util/CurrentInstance.java | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/server/src/com/vaadin/util/CurrentInstance.java b/server/src/com/vaadin/util/CurrentInstance.java index 39c2a60a5c..4c62ef49be 100644 --- a/server/src/com/vaadin/util/CurrentInstance.java +++ b/server/src/com/vaadin/util/CurrentInstance.java @@ -237,6 +237,22 @@ public class CurrentInstance implements Serializable { if (v == null) { removeStale = true; } else if (v == NULL_OBJECT) { + /* + * NULL_OBJECT is used to identify objects that are null when + * #setCurrent(UI) or #setCurrent(VaadinSession) are called on a + * CurrentInstance. Without this a reference to an already + * collected instance may be left in the CurrentInstance when it + * really should be restored to null. + * + * One example case that this fixes: + * VaadinService.runPendingAccessTasks() clears all current + * instances and then sets everything but the UI. This makes + * UI.accessSynchronously() save these values before calling + * setCurrent(UI), which stores UI=null in the map it returns. + * This map will be restored after UI.accessSync(), which, + * unless it respects null values, will just leave the wrong UI + * instance registered. + */ set(c, null, ci.inheritable); } else { set(c, v, ci.inheritable); |