fix(move): redraw for 'concealcursor' after changing w_wcol (#31276)

src/nvim/move.c

@@ -150,25 +150,20 @@ static void redraw_for_cursorline(win_T *wp)
   }
 }
 
-/// Redraw when w_virtcol changes and
+/// Redraw when 'concealcursor' is active, or when w_virtcol changes and:
 /// - 'cursorcolumn' is set, or
 /// - 'cursorlineopt' contains "screenline", or
-/// - 'concealcursor' is active, or
 /// - Visual mode is active.
 static void redraw_for_cursorcolumn(win_T *wp)
   FUNC_ATTR_NONNULL_ALL
 {
-  if (wp->w_valid & VALID_VIRTCOL) {
-    return;
-  }
-
   // If the cursor moves horizontally when 'concealcursor' is active, then the
   // current line needs to be redrawn to calculate the correct cursor position.
   if (wp->w_p_cole > 0 && conceal_cursor_line(wp)) {
     redrawWinline(wp, wp->w_cursor.lnum);
   }
 
-  if (pum_visible()) {
+  if ((wp->w_valid & VALID_VIRTCOL) || pum_visible()) {
     return;
   }
 

test/functional/ui/syntax_conceal_spec.lua

@@ -198,7 +198,7 @@ describe('Screen', function()
       end)
     end) -- a region of text (implicit concealing)
 
-    it('cursor position is correct when entering Insert mode with cocu=ni #13916', function()
+    it('cursor position when entering Insert mode with cocu=ni #13916', function()
       insert([[foobarfoobarfoobar]])
       -- move to end of line
       feed('$')
@@ -217,6 +217,37 @@ describe('Screen', function()
         {4:-- INSERT --}                                         |
       ]])
     end)
+
+    it('cursor position when scrolling in Normal mode with cocu=n #31271', function()
+      insert(('foo\n'):rep(9) .. 'foofoobarfoofoo' .. ('\nfoo'):rep(9))
+      command('set concealcursor=n')
+      command('syn match Foo /bar/ conceal cchar=&')
+      feed('gg5<C-E>10gg$')
+      screen:expect([[
+        foo                                                  |*4
+        foofoo{1:&}foofo^o                                        |
+        foo                                                  |*4
+                                                             |
+      ]])
+      feed('zz')
+      screen:expect_unchanged()
+      feed('zt')
+      screen:expect([[
+        foofoo{1:&}foofo^o                                        |
+        foo                                                  |*8
+                                                             |
+      ]])
+      feed('zt')
+      screen:expect_unchanged()
+      feed('zb')
+      screen:expect([[
+        foo                                                  |*8
+        foofoo{1:&}foofo^o                                        |
+                                                             |
+      ]])
+      feed('zb')
+      screen:expect_unchanged()
+    end)
   end) -- match and conceal
 
   describe('let the conceal level be', function()