From c0daea3afd6a1e502e282a235a10643c785301f7 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Sat, 16 Mar 2024 17:10:20 +0800
Subject: [PATCH] vim-patch:9.1.0183: Wrong display or screenpos() result when
 toggling diff mode (#27882)

Problem:  Wrong display or screenpos() result when toggling diff mode.
Solution: Reset w_skipcol when disabling 'wrap'.  Reset w_leftcol when
          enabling 'wrap' (zeertzjq).

fixes: vim/vim#14210
closes: vim/vim#14211

https://github.com/vim/vim/commit/9e7f1fc2f159d58b2a4cd4b7060bead126fead49
---
 src/nvim/diff.c                    |  6 ++-
 test/old/testdir/test_diffmode.vim | 67 ++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index c680600d39..39d9e9e978 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -1429,6 +1429,7 @@ void diff_win_options(win_T *wp, bool addbuf)
       wp->w_p_wrap_save = wp->w_p_wrap;
     }
     wp->w_p_wrap = false;
+    wp->w_skipcol = 0;
   }
 
   if (!wp->w_p_diff) {
@@ -1497,8 +1498,9 @@ void ex_diffoff(exarg_T *eap)
           wp->w_p_crb = wp->w_p_crb_save;
         }
         if (!(diff_flags & DIFF_FOLLOWWRAP)) {
-          if (!wp->w_p_wrap) {
-            wp->w_p_wrap = wp->w_p_wrap_save;
+          if (!wp->w_p_wrap && wp->w_p_wrap_save) {
+            wp->w_p_wrap = true;
+            wp->w_leftcol = 0;
           }
         }
         free_string_option(wp->w_p_fdm);
diff --git a/test/old/testdir/test_diffmode.vim b/test/old/testdir/test_diffmode.vim
index 9a3e006430..c1a63a6f88 100644
--- a/test/old/testdir/test_diffmode.vim
+++ b/test/old/testdir/test_diffmode.vim
@@ -3,6 +3,7 @@
 source shared.vim
 source screendump.vim
 source check.vim
+source view_util.vim
 
 func Test_diff_fold_sync()
   enew!
@@ -1702,4 +1703,70 @@ func Test_diff_put_and_undo()
 endfunc
 
 
+func Test_diff_toggle_wrap_skipcol_leftcol()
+  61vnew
+  call setline(1, 'Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.')
+  30vnew
+  call setline(1, 'ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.')
+  let win1 = win_getid()
+  setlocal smoothscroll
+  exe "normal! $\<C-E>"
+  wincmd l
+  let win2 = win_getid()
+  setlocal smoothscroll
+  exe "normal! $\<C-E>"
+  call assert_equal([
+        \ '<<<sadipscing elitr, sed diam |<<<tetur sadipscing elitr, sed|',
+        \ 'nonumy eirmod tempor invidunt | diam nonumy eirmod tempor inv|',
+        \ 'ut labore et dolore magna aliq|idunt ut labore et dolore magn|',
+        \ 'uyam erat, sed diam voluptua. |a aliquyam erat, sed diam volu|',
+        \ '~                             |ptua.                         |',
+        \ ], ScreenLines([1, 5], 62))
+  call assert_equal({'col': 29, 'row': 4, 'endcol': 29, 'curscol': 29},
+        \ screenpos(win1, line('.', win1), col('.', win1)))
+  call assert_equal({'col': 36, 'row': 5, 'endcol': 36, 'curscol': 36},
+        \ screenpos(win2, line('.', win2), col('.', win2)))
+
+  wincmd h
+  diffthis
+  wincmd l
+  diffthis
+  normal! 0
+  call assert_equal([
+        \ '  ipsum dolor sit amet, conset|  Lorem ipsum dolor sit amet, |',
+        \ '~                             |~                             |',
+        \ ], ScreenLines([1, 2], 62))
+  call assert_equal({'col': 3, 'row': 1, 'endcol': 3, 'curscol': 3},
+        \ screenpos(win1, line('.', win1), col('.', win1)))
+  call assert_equal({'col': 34, 'row': 1, 'endcol': 34, 'curscol': 34},
+        \ screenpos(win2, line('.', win2), col('.', win2)))
+
+  normal! $
+  call assert_equal([
+        \ '  voluptua.                   |   diam voluptua.             |',
+        \ '~                             |~                             |',
+        \ ], ScreenLines([1, 2], 62))
+  call assert_equal({'col': 11, 'row': 1, 'endcol': 11, 'curscol': 11},
+        \ screenpos(win1, line('.', win1), col('.', win1)))
+  call assert_equal({'col': 48, 'row': 1, 'endcol': 48, 'curscol': 48},
+        \ screenpos(win2, line('.', win2), col('.', win2)))
+
+  diffoff!
+  call assert_equal([
+        \ 'ipsum dolor sit amet, consetet|Lorem ipsum dolor sit amet, co|',
+        \ 'ur sadipscing elitr, sed diam |nsetetur sadipscing elitr, sed|',
+        \ 'nonumy eirmod tempor invidunt | diam nonumy eirmod tempor inv|',
+        \ 'ut labore et dolore magna aliq|idunt ut labore et dolore magn|',
+        \ 'uyam erat, sed diam voluptua. |a aliquyam erat, sed diam volu|',
+        \ '~                             |ptua.                         |',
+        \ ], ScreenLines([1, 6], 62))
+  call assert_equal({'col': 29, 'row': 5, 'endcol': 29, 'curscol': 29},
+        \ screenpos(win1, line('.', win1), col('.', win1)))
+  call assert_equal({'col': 36, 'row': 6, 'endcol': 36, 'curscol': 36},
+        \ screenpos(win2, line('.', win2), col('.', win2)))
+
+  bwipe!
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab