vim-patch:8.1.1552: cursor position is wrong after sign column changes

Problem:    Cursor position is wrong after sign column appears or disappears.
            (Yegappan Lakshmanan)
Solution:   Call changed_line_abv_curs() instead of changed_cline_bef_curs().
https://github.com/vim/vim/commit/f85e40afc204c241c6a01023be3e7b8101d36367

2 files changed, 35 insertions, 5 deletions

diff --git a/src/nvim/sign.c b/src/nvim/sign.c
index baa9c6538f..079e95ada8 100644
--- a/src/nvim/sign.c
+++ b/src/nvim/sign.c
@@ -198,7 +198,7 @@ static void insert_sign(
     // column for signs.
     if (buf->b_signlist == NULL) {
       redraw_buf_later(buf, NOT_VALID);
-      changed_cline_bef_curs();
+      changed_line_abv_curs();
     }
 
     // first sign in signlist
@@ -495,11 +495,11 @@ linenr_T buf_delsign(
     }
   }
 
-  // When deleted the last sign needs to redraw the windows to remove the
-  // sign column.
+  // When deleting the last sign the cursor position may change, because the
+  // sign columns no longer shows.  And the 'signcolumn' may be hidden.
   if (buf->b_signlist == NULL) {
     redraw_buf_later(buf, NOT_VALID);
-    changed_cline_bef_curs();
+    changed_line_abv_curs();
   }
 
   return lnum;
@@ -572,7 +572,7 @@ void buf_delete_signs(buf_T *buf, char_u *group)
     // When deleting the last sign need to redraw the windows to remove the
     // sign column. Not when curwin is NULL (this means we're exiting).
     if (buf->b_signlist != NULL && curwin != NULL) {
-      changed_cline_bef_curs();
+      changed_line_abv_curs();
     }
 
     lastp = &buf->b_signlist;
diff --git a/src/nvim/testdir/test_signs.vim b/src/nvim/testdir/test_signs.vim
index 6af81e15c5..dcbb546a2e 100644
--- a/src/nvim/testdir/test_signs.vim
+++ b/src/nvim/testdir/test_signs.vim
@@ -4,6 +4,8 @@ if !has('signs')
   finish
 endif
 
+source screendump.vim
+
 func Test_sign()
   new
   call setline(1, ['a', 'b', 'c', 'd'])
@@ -1652,3 +1654,31 @@ func Test_sign_jump_func()
   sign undefine sign1
   enew! | only!
 endfunc
+
+" Test for correct cursor position after the sign column appears or disappears.
+func Test_sign_cursor_position()
+  if !CanRunVimInTerminal()
+    throw 'Skipped: cannot make screendumps'
+  endif
+
+  let lines =<< trim END
+	call setline(1, [repeat('x', 75), 'mmmm', 'yyyy'])
+	call cursor(2,1)
+   	sign define s1 texthl=Search text==>
+	redraw
+   	sign place 10 line=2 name=s1
+  END
+  call writefile(lines, 'XtestSigncolumn')
+  let buf = RunVimInTerminal('-S XtestSigncolumn', {'rows': 6})
+  call VerifyScreenDump(buf, 'Test_sign_cursor_01', {})
+
+  " update cursor position calculation
+  call term_sendkeys(buf, "lh")
+  call term_sendkeys(buf, ":sign unplace 10\<CR>")
+  call VerifyScreenDump(buf, 'Test_sign_cursor_02', {})
+
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('XtestSigncolumn')
+endfunc