From 6d8b93ce84411075541ec9b21f07abd424ebd345 Mon Sep 17 00:00:00 2001
From: Nick Hall <nick-h@gramps-project.org>
Date: Sat, 29 Jul 2023 22:31:03 +0100
Subject: [PATCH] Allow custom undo managers in database plugins

Add a _create_undo_manager method in DbGeneric which can be
overridden to supply a custom undo manager rather than the
default DbGenericUndo.
---
 gramps/gen/db/generic.py  | 10 ++++++++--
 gramps/gen/db/undoredo.py |  7 +++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/gramps/gen/db/generic.py b/gramps/gen/db/generic.py
index 59410209671..674a9aa9216 100644
--- a/gramps/gen/db/generic.py
+++ b/gramps/gen/db/generic.py
@@ -626,11 +626,11 @@ def load(self, directory, callback=None, mode=DBMODE_W,
 
         self._set_save_path(directory)
 
-        if self._directory:
+        if self._directory and self._directory != ":memory:":
             self.undolog = os.path.join(self._directory, DBUNDOFN)
         else:
             self.undolog = None
-        self.undodb = DbGenericUndo(self, self.undolog)
+        self.undodb = self._create_undo_manager()
         self.undodb.open()
 
         # Other items to load
@@ -665,6 +665,12 @@ def load(self, directory, callback=None, mode=DBMODE_W,
                 self.close()
                 raise DbUpgradeRequiredError(dbversion, self.VERSION[0])
 
+    def _create_undo_manager(self):
+        """
+        Create the undo manager.
+        """
+        return DbGenericUndo(self, self.undolog)
+
     def _close(self):
         """
         Close database backend.
diff --git a/gramps/gen/db/undoredo.py b/gramps/gen/db/undoredo.py
index a8bff6784c8..51fa9dc2d38 100644
--- a/gramps/gen/db/undoredo.py
+++ b/gramps/gen/db/undoredo.py
@@ -125,6 +125,13 @@ def commit(self, txn, msg):
         txn.set_description(msg)
         txn.timestamp = time.time()
         self.undoq.append(txn)
+        self._after_commit(txn)
+
+    def _after_commit(self, transaction):
+        """
+        Post-transaction commit processing.
+        """
+        pass
 
     def undo(self, update_history=True):
         """