Re: master f450798: Don't move point in vc-dir on vc-register/vc-checkin (bug#43188)

[Andrii Kolomoiets <andreyk.mad@gmail.com>]

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Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> -		      (ewoc-invalidate vc-ewoc node))
>> +                      ;; `ewoc-invalidate' will kill line and insert new text,
>> +                      ;; let's keep point column.
>> +                      (let ((p (point)))
>> +		        (ewoc-invalidate vc-ewoc node)
>> +                        (goto-char p)))
>
> Shouldn't this be done in `ewoc-invalidate` instead?

Good point!  According 'ewoc-invalidate' docstring, refreshing is done
by deleting the text and inserting the new one thus the 'save-excursion'
is not really helpful.

Please see attached patch.

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From 6f07dca7bff37c6ca7e98f38e8613445d3e8ea32 Mon Sep 17 00:00:00 2001
From: Andrii Kolomoiets <andreyk.mad@gmail.com>
Date: Sat, 5 Sep 2020 22:18:59 +0300
Subject: [PATCH] Save and restore point in ewoc-invalidate

* lisp/emacs-lisp/ewoc.el (ewoc-invalidate): Use 'goto-char' instead of
'save-excursion'.
* lisp/vc/vc-dir.el (vc-dir-update): Don't save/restore point on calling
'ewoc-invalidate'.
---
 lisp/emacs-lisp/ewoc.el | 5 +++--
 lisp/vc/vc-dir.el       | 6 +-----
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/lisp/emacs-lisp/ewoc.el b/lisp/emacs-lisp/ewoc.el
index 78ada3e076..7244fd9359 100644
--- a/lisp/emacs-lisp/ewoc.el
+++ b/lisp/emacs-lisp/ewoc.el
@@ -461,9 +461,10 @@ ewoc-invalidate
 Delete current text first, thus effecting a \"refresh\"."
   (ewoc--set-buffer-bind-dll-let* ewoc
       ((pp (ewoc--pretty-printer ewoc)))
-    (save-excursion
+    (let ((p (point)))
       (dolist (node nodes)
-        (ewoc--refresh-node pp node dll)))))
+        (ewoc--refresh-node pp node dll))
+      (goto-char p))))
 
 (defun ewoc-goto-prev (ewoc arg)
   "Move point to the ARGth previous element in EWOC.
diff --git a/lisp/vc/vc-dir.el b/lisp/vc/vc-dir.el
index 6c219005ce..cdf8ab984e 100644
--- a/lisp/vc/vc-dir.el
+++ b/lisp/vc/vc-dir.el
@@ -451,11 +451,7 @@ vc-dir-update
 		      (setf (vc-dir-fileinfo->state (ewoc-data node)) (nth 1 entry))
 		      (setf (vc-dir-fileinfo->extra (ewoc-data node)) (nth 2 entry))
 		      (setf (vc-dir-fileinfo->needs-update (ewoc-data node)) nil)
-                      ;; `ewoc-invalidate' will kill line and insert new text,
-                      ;; let's keep point column.
-                      (let ((p (point)))
-		        (ewoc-invalidate vc-ewoc node)
-                        (goto-char p)))
+		      (ewoc-invalidate vc-ewoc node))
 		  ;; If the state is nil, the file does not exist
 		  ;; anymore, so remember the entry so we can remove
 		  ;; it after we are done inserting all ENTRIES.
-- 
2.15.1