From: Yuan Fu <casouri@gmail.com>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel <emacs-devel@gnu.org>
Subject: Re: Distinguish between regional undo and undo to the beginning in undo-equiv-table
Date: Wed, 3 Mar 2021 15:33:13 -0500 [thread overview]
Message-ID: <4890CDDF-E0DD-464B-9268-AD404015129D@gmail.com> (raw)
In-Reply-To: <jwvy2f4gp6k.fsf-monnier+emacs@gnu.org>
[-- Attachment #1: Type: text/plain, Size: 764 bytes --]
>
> Thanks a lot (especially for improving the docstring ;-). In my
> experience, this part of the code is quite delicate and I wouldn't be
> surprised to find yet more bugs for other corner cases. So I think it's
> very important to document those corner cases with tests. Any chance
> you could add matching tests to test/lisp/simple-tests.el in your patch?
>
This patch applies on top of the first one. I added more docstrings since you seem to appreciate it. I came up with some simple test cases for ordinary mapping, t and ‘undo-in-region in the table. Do you have other corner cases in mind? I also added some simple test cases for undo in region. I couldn’t wrap my head around the original tests so I started a new one below.
Yuan
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From 72bbfd0e0d4c8a4175e44ccee49323323c018834 Mon Sep 17 00:00:00 2001
From: Yuan Fu <casouri@gmail.com>
Date: Wed, 3 Mar 2021 15:07:00 -0500
Subject: [PATCH] checkpoint
---
lisp/simple.el | 17 ++++++++-
test/lisp/simple-tests.el | 75 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 90 insertions(+), 2 deletions(-)
diff --git a/lisp/simple.el b/lisp/simple.el
index 05bf4b8784..8265639305 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -2826,7 +2826,22 @@ undo-equiv-table
"Table mapping redo records to the corresponding undo one.
A redo record for undo-in-region maps to 'undo-in-region.
A redo record for ordinary undo maps to the following (earlier) undo.
-An undo record that undoes to the beginning of the undo list maps to t.")
+An undo record that undoes to the beginning of the undo list maps to t.
+
+When you undo, the `pending-undo-list' shrinks and
+`buffer-undo-list' grows, and Emacs maps the tip of
+`buffer-undo-list' to the tip of `pending-undo-list' in this
+table.
+
+For example, consider this undo list where each node represents an
+undo record, if we undo from 4, `pending-undo-list' will be at 3,
+`buffer-undo-list' at 5, and 5 will map to 3.
+
+ |
+ 3 5
+ | /
+ |/
+ 4")
(defvar undo-in-region nil
"Non-nil if `pending-undo-list' is not just a tail of `buffer-undo-list'.")
diff --git a/test/lisp/simple-tests.el b/test/lisp/simple-tests.el
index f2ddc2e3fb..a4816951ce 100644
--- a/test/lisp/simple-tests.el
+++ b/test/lisp/simple-tests.el
@@ -465,8 +465,81 @@ simple-tests--undo
(simple-tests--exec '(backward-char undo-redo undo-redo))
(should (equal (buffer-string) "abc"))
(simple-tests--exec '(backward-char undo-redo undo-redo))
+ (should (equal (buffer-string) "abcde")))
+ ;; Test undo/redo in region.
+ (with-temp-buffer
+ (buffer-enable-undo)
+ (dolist (x '("a" "b" "c" "d" "e"))
+ (insert x)
+ (undo-boundary))
(should (equal (buffer-string) "abcde"))
- ))
+ (simple-tests--exec '(move-beginning-of-line
+ push-mark-command
+ forward-char
+ forward-char
+ undo))
+ (should (equal (buffer-string) "acde"))
+ (simple-tests--exec '(undo-only))
+ (should (equal (buffer-string) "cde"))
+ (simple-tests--exec '(undo-redo))
+ (should (equal (buffer-string) "acde"))
+ (simple-tests--exec '(undo-redo))
+ (should (equal (buffer-string) "abcde"))))
+
+(defun simple-tests--sans-leading-nil (lst)
+ "Return LST sans the leading nils."
+ (while (and (consp lst) (null (car lst)))
+ (setq lst (cdr lst)))
+ lst)
+
+(ert-deftest simple-tests--undo-equiv-table ()
+ (with-temp-buffer
+ (buffer-enable-undo)
+ (let ((ul-hash-table (make-hash-table :test #'equal)))
+ (dolist (x '("a" "b" "c"))
+ (insert x)
+ (puthash x (simple-tests--sans-leading-nil buffer-undo-list)
+ ul-hash-table)
+ (undo-boundary))
+ (should (equal (buffer-string) "abc"))
+
+ ;; Tests mappings in `undo-equiv-table'.
+ (simple-tests--exec '(undo))
+ (should (equal (buffer-string) "ab"))
+ (should (eq (gethash (simple-tests--sans-leading-nil
+ buffer-undo-list)
+ undo-equiv-table)
+ (gethash "b" ul-hash-table)))
+
+ (simple-tests--exec '(backward-char undo))
+ (should (equal (buffer-string) "abc"))
+ (should (eq (gethash (simple-tests--sans-leading-nil
+ buffer-undo-list)
+ undo-equiv-table)
+ (gethash "c" ul-hash-table)))
+
+ ;; Undo in region should map to 'undo-in-region.
+ (simple-tests--exec '(backward-char
+ push-mark-command
+ move-end-of-line
+ undo))
+ (should (equal (buffer-string) "ab"))
+ (should (eq (gethash (simple-tests--sans-leading-nil
+ buffer-undo-list)
+ undo-equiv-table)
+ 'undo-in-region))
+
+ ;; The undo that undoes to the beginning should map to t.
+ (deactivate-mark 'force)
+ (simple-tests--exec '(backward-char
+ undo undo undo
+ undo undo undo))
+ (should (equal (buffer-string) ""))
+ (should (eq (gethash (simple-tests--sans-leading-nil
+ buffer-undo-list)
+ undo-equiv-table)
+ t))
+ )))
;;; undo auto-boundary tests
(ert-deftest undo-auto-boundary-timer ()
--
2.24.3 (Apple Git-128)
next prev parent reply other threads:[~2021-03-03 20:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 20:40 Distinguish between regional undo and undo to the beginning in undo-equiv-table Yuan Fu
2021-03-02 23:50 ` Stefan Monnier
2021-03-03 15:42 ` Yuan Fu
2021-03-03 16:50 ` Stefan Monnier
2021-03-03 20:33 ` Yuan Fu [this message]
2021-03-03 21:29 ` Stefan Monnier
2021-03-03 21:59 ` Yuan Fu
2021-03-03 22:08 ` Yuan Fu
2021-03-03 22:28 ` Stefan Monnier
2021-03-04 16:18 ` Yuan Fu
2021-03-05 15:57 ` Stefan Monnier
2021-03-06 17:28 ` Yuan Fu
2021-03-06 18:40 ` Stefan Monnier
2021-03-11 17:50 ` Yuan Fu
2021-03-11 17:54 ` Stefan Monnier
2021-03-11 21:23 ` Yuan Fu
2021-03-11 22:41 ` Stefan Monnier
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