Trigger ein:notebook-empty-undo-maybe via event

Previous tests were failed because undo was not reset after the
execution callbacks modified the buffer.  This is fixed by calling
ein:notebook-empty-undo-maybe via event in all the callbacks.

ein-cell.el

@@ -794,12 +794,15 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
 (defmethod ein:cell--handle-execute-reply ((cell ein:codecell) content)
   (ein:cell-set-input-prompt cell (plist-get content :execution_count))
   (ein:cell-running-set cell nil)
-  (ein:events-trigger
-   (oref cell :events) 'set_dirty.Notebook '(:value t)))
+  (let ((events (oref cell :events)))
+    (ein:events-trigger events 'set_dirty.Notebook '(:value t))
+    (ein:events-trigger events 'maybe_reset_undo.Notebook)))
 
 (defmethod ein:cell--handle-set-next-input ((cell ein:codecell) text)
-  (ein:events-trigger
-   (oref cell :events) 'set_next_input.Notebook (list :cell cell :text text)))
+  (let ((events (oref cell :events)))
+    (ein:events-trigger events 'set_next_input.Notebook
+                        (list :cell cell :text text))
+    (ein:events-trigger events 'maybe_reset_undo.Notebook)))
 
 
 
@@ -826,7 +829,7 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
        (plist-put json :traceback (plist-get content :traceback))))
     (ein:cell-append-output cell json t)
     ;; (oset cell :dirty t)
-    ))
+    (ein:events-trigger (oref cell :events) 'maybe_reset_undo.Notebook)))
 
 
 (defun ein:output-area-convert-mime-types (json data)
@@ -848,7 +851,8 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
   (ein:cell-clear-output cell
                          (plist-get content :stdout)
                          (plist-get content :stderr)
-                         (plist-get content :other)))
+                         (plist-get content :other))
+  (ein:events-trigger (oref cell :events) 'maybe_reset_undo.Notebook))
 
 
 ;;; Misc.

ein-events.el

@@ -62,7 +62,9 @@
 When EVENT-TYPE is triggered on the event handler EVENTS,
 CALLBACK is called.  CALLBACK must take two arguments:
 ARG as the first argument and DATA, which is passed via
-`ein:events-trigger', as the second."
+`ein:events-trigger', as the second.  When calling the function,
+current buffer is set to the configured buffer.  `ein:events-new'
+is used to configure the buffer."
   (assert (symbolp event-type))
   (let* ((table (oref events :callbacks))
          (cbs (gethash event-type table)))

ein-notebook.el

@@ -356,6 +356,10 @@ See `ein:notebook-open' for more information."
                    (setf (ein:$notebook-dirty notebook)
                          (plist-get data :value)))
                  notebook)
+  (ein:events-on events
+                 'maybe_reset_undo.Notebook
+                 (lambda (&rest -ignore-)
+                   (ein:notebook-empty-undo-maybe)))
   ;; Bind events for sub components:
   (mapc (lambda (cell) (oset cell :events (ein:$notebook-events notebook)))
         (ein:notebook-get-cells notebook))

tests/test-ein-notebook.el

@@ -49,8 +49,7 @@
     (with-current-buffer (ein:notebook-request-open-callback
                           (ein:notebook-new "DUMMY-URL" notebook-id)
                           :data (ein:json-read-from-string json-string))
-      (let ((events (ein:events-new (current-buffer))))
-        (setf (ein:$notebook-events ein:notebook) events)
+      (let ((events (ein:$notebook-events ein:notebook)))
         (setf (ein:$notebook-kernel ein:notebook)
               (ein:kernel-new 8888 "/kernels" events)))
       (current-buffer))))