[nongnu] elpa/undo-fu 2b1e53285a 55/82: Fix checkpoint initialization with undo data from undo-fu-session

[ELPA Syncer]

branch: elpa/undo-fu
commit 2b1e53285a55ce50ca6fd60b050f2171e235d8f9
Author: Campbell Barton <ideasman42@gmail.com>
Commit: Campbell Barton <ideasman42@gmail.com>

    Fix checkpoint initialization with undo data from undo-fu-session
---
 changelog.rst | 2 ++
 undo-fu.el    | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/changelog.rst b/changelog.rst
index bf33687479..57787c5684 100644
--- a/changelog.rst
+++ b/changelog.rst
@@ -5,6 +5,8 @@ Change Log
 
 - In development
 
+  - Fix undo checkpoint initialization when running for the first with 
existing undo data.
+    This could happen when running undo immediately upon loading a file with 
undo data from ``undo-fu-session``.
   - Undo in *unconstrained* mode no longer uses ``undo-only``,
     matching redo behavior.
   - Raise an error when using undo commands when undo has been disabled for 
the buffer.
diff --git a/undo-fu.el b/undo-fu.el
index a9ded87138..ac70a1ef67 100644
--- a/undo-fu.el
+++ b/undo-fu.el
@@ -358,6 +358,12 @@ Optional argument ARG the number of steps to undo."
           'undo-fu-disable-checkpoint
           'keyboard-quit)))
 
+    ;; Special case, for first execution, `was-undo-or-redo' may be true
+    ;; based on saved undo history, yet the `undo-fu--checkpoint' can be nil.
+    ;; In this case it's simplest to behave as if the last command was not 
undo.
+    (when (and was-undo-or-redo undo-fu--respect (null undo-fu--checkpoint))
+      (setq was-undo-or-redo nil))
+
     ;; Reset the option to not respect the checkpoint
     ;; after running non-undo related commands.
     (unless undo-fu--respect