vim-patch:9.1.1250: cannot set the maximum popup menu width

Problem:  cannot set the maximum popup menu width
          (Lucas Mior)
Solution: add the new global option value 'pummaxwidth'
          (glepnir)

fixes: vim/vim#10901
closes: vim/vim#16943

https://github.com/vim/vim/commit/88d75934c3d5bc4c406343f106e1a61638abd3a7

Co-authored-by: glepnir <glephunter@gmail.com>

9 files changed, 507 insertions, 3 deletions

diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
index aa6af1ef55..5f47c474a7 100644
--- a/runtime/doc/news.txt
+++ b/runtime/doc/news.txt
@@ -79,6 +79,7 @@ LUA
 OPTIONS
 
 • 'diffopt' `inline:` configures diff highlighting for changes within a line.
+• 'pummaxwidth' sets maximum width for the completion popup menu.
 
 PLUGINS
 
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index ada4e250bc..bdc4f20fac 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -4623,6 +4623,14 @@ A jump table for the options with a short description can be found at |Q_op|.
 	Maximum number of items to show in the popup menu
 	(|ins-completion-menu|). Zero means "use available screen space".
 
+						*'pummaxwidth'* *'pmw'*
+'pummaxwidth' 'pmw'	number	(default 0)
+			global
+	Maximum width for the popup menu (|ins-completion-menu|).  When zero,
+	there is no maximum width limit, otherwise the popup menu will never be
+	wider than this value.  Truncated text will be indicated by "..." at the
+	end.  Takes precedence over 'pumwidth'.
+
 						*'pumwidth'* *'pw'*
 'pumwidth' 'pw'		number	(default 15)
 			global
diff --git a/runtime/lua/vim/_meta/options.lua b/runtime/lua/vim/_meta/options.lua
index 5f93e42c35..9ff4770e7c 100644
--- a/runtime/lua/vim/_meta/options.lua
+++ b/runtime/lua/vim/_meta/options.lua
@@ -4802,6 +4802,17 @@ vim.o.ph = vim.o.pumheight
 vim.go.pumheight = vim.o.pumheight
 vim.go.ph = vim.go.pumheight
 
+--- Maximum width for the popup menu (`ins-completion-menu`).  When zero,
+--- there is no maximum width limit, otherwise the popup menu will never be
+--- wider than this value.  Truncated text will be indicated by "..." at the
+--- end.  Takes precedence over 'pumwidth'.
+---
+--- @type integer
+vim.o.pummaxwidth = 0
+vim.o.pmw = vim.o.pummaxwidth
+vim.go.pummaxwidth = vim.o.pummaxwidth
+vim.go.pmw = vim.go.pummaxwidth
+
 --- Minimum width for the popup menu (`ins-completion-menu`).  If the
 --- cursor column + 'pumwidth' exceeds screen width, the popup menu is
 --- nudged to fit on the screen.
diff --git a/runtime/optwin.vim b/runtime/optwin.vim
index 56fbb954a7..41f9fc0373 100644
--- a/runtime/optwin.vim
+++ b/runtime/optwin.vim
@@ -1,7 +1,7 @@
 " These commands create the option window.
 "
 " Maintainer:	The Vim Project <https://github.com/vim/vim>
-" Last Change:	2025 Mar 07
+" Last Change:	2025 Mar 27
 " Former Maintainer:	Bram Moolenaar <Bram@vim.org>
 
 " If there already is an option window, jump to that one.
@@ -736,6 +736,8 @@ if has("insert_expand")
   call <SID>OptionG("ph", &ph)
   call <SID>AddOption("pumwidth", gettext("minimum width of the popup menu"))
   call <SID>OptionG("pw", &pw)
+  call <SID>AddOption("pumaxmwidth", gettext("maximum width of the popup menu"))
+  call <SID>OptionG("pmw", &pmw)
   call <SID>AddOption("completefunc", gettext("user defined function for Insert mode completion"))
   call append("$", "\t" .. s:local_to_buffer)
   call <SID>OptionL("cfu")
diff --git a/src/nvim/option_vars.h b/src/nvim/option_vars.h
index 0b5d0a45b4..e624ab80ef 100644
--- a/src/nvim/option_vars.h
+++ b/src/nvim/option_vars.h
@@ -306,6 +306,7 @@ EXTERN char *p_csl;             ///< 'completeslash'
 EXTERN OptInt p_pb;             ///< 'pumblend'
 EXTERN OptInt p_ph;             ///< 'pumheight'
 EXTERN OptInt p_pw;             ///< 'pumwidth'
+EXTERN OptInt p_pmw;            ///< 'pummaxwidth'
 EXTERN char *p_com;             ///< 'comments'
 EXTERN char *p_cpo;             ///< 'cpoptions'
 EXTERN char *p_debug;           ///< 'debug'
diff --git a/src/nvim/options.lua b/src/nvim/options.lua
index 2f77d0ebb7..f261abf30e 100644
--- a/src/nvim/options.lua
+++ b/src/nvim/options.lua
@@ -6426,6 +6426,21 @@ local options = {
       varname = 'p_ph',
     },
     {
+      abbreviation = 'pmw',
+      defaults = 0,
+      desc = [=[
+        Maximum width for the popup menu (|ins-completion-menu|).  When zero,
+        there is no maximum width limit, otherwise the popup menu will never be
+        wider than this value.  Truncated text will be indicated by "..." at the
+        end.  Takes precedence over 'pumwidth'.
+      ]=],
+      full_name = 'pummaxwidth',
+      scope = { 'global' },
+      short_desc = N_('maximum width of the popup menu'),
+      type = 'number',
+      varname = 'p_pmw',
+    },
+    {
       abbreviation = 'pw',
       defaults = 15,
       desc = [=[
diff --git a/src/nvim/popupmenu.c b/src/nvim/popupmenu.c
index d26651fb84..75f1c93ed7 100644
--- a/src/nvim/popupmenu.c
+++ b/src/nvim/popupmenu.c
@@ -199,6 +199,9 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
     }
 
     int def_width = (int)p_pw;
+    if (p_pmw > 0 && def_width > p_pmw) {
+      def_width = (int)p_pmw;
+    }
 
     win_T *pvwin = NULL;
     FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
@@ -307,6 +310,9 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
 
     pum_compute_size();
     int max_width = pum_base_width;
+    if (p_pmw > 0 && max_width > p_pmw) {
+      max_width = (int)p_pmw;
+    }
 
     // if there are more items than room we need a scrollbar
     if (pum_height < size) {
@@ -339,6 +345,9 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
       if (pum_width > content_width && pum_width > p_pw) {
         // Reduce width to fit item
         pum_width = MAX(content_width, (int)p_pw);
+        if (p_pmw > 0 && pum_width > p_pmw) {
+          pum_width = (int)p_pmw;
+        }
       } else if (((cursor_col - min_col > p_pw
                    || cursor_col - min_col > max_width) && !pum_rl)
                  || (pum_rl && (cursor_col < max_col - p_pw
@@ -365,6 +374,9 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
 
         if (pum_width < p_pw) {
           pum_width = (int)p_pw;
+          if (p_pmw > 0 && pum_width > p_pmw) {
+            pum_width = (int)p_pmw;
+          }
           if (pum_rl) {
             if (pum_width > pum_col - min_col) {
               pum_width = pum_col - min_col;
@@ -376,6 +388,9 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
           }
         } else if (pum_width > content_width && pum_width > p_pw) {
           pum_width = MAX(content_width, (int)p_pw);
+          if (p_pmw > 0 && pum_width > p_pmw) {
+            pum_width = (int)p_pmw;
+          }
         }
       }
     } else if (max_col - min_col < def_width) {
@@ -386,11 +401,17 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
         pum_col = min_col;
       }
       pum_width = max_col - min_col - 1;
+      if (p_pmw > 0 && pum_width > p_pmw) {
+        pum_width = (int)p_pmw;
+      }
     } else {
       if (max_width > p_pw) {
         // truncate
         max_width = (int)p_pw;
       }
+      if (p_pmw > 0 && max_width > p_pmw) {
+        max_width = (int)p_pmw;
+      }
       if (pum_rl) {
         pum_col = min_col + max_width - 1;
       } else {
@@ -611,6 +632,8 @@ void pum_redraw(void)
     thumb_pos = (pum_first * (pum_height - thumb_height) + scroll_range / 2) / scroll_range;
   }
 
+  const int ellipsis_width = 3;
+
   for (int i = 0; i < pum_height; i++) {
     int idx = i + pum_first;
     const hlf_T *const hlfs = (idx == pum_selected) ? hlfsSel : hlfsNorm;
@@ -685,6 +708,9 @@ void pum_redraw(void)
             char *rt = reverse_text(st);
             char *rt_start = rt;
             int cells = vim_strsize(rt);
+            bool need_ellipsis = p_pmw > ellipsis_width
+                                 && pum_width == p_pmw
+                                 && grid_col - cells < col_off - pum_width;
 
             if (grid_col - cells < col_off - pum_width) {
               do {
@@ -692,7 +718,41 @@ void pum_redraw(void)
                 MB_PTR_ADV(rt);
               } while (grid_col - cells < col_off - pum_width);
 
-              if (grid_col - cells > col_off - pum_width) {
+              if (need_ellipsis) {
+                char *orig_rt = rt;
+                int used_cells = 0;
+                char *last_char = NULL;
+                while (*orig_rt != NUL) {
+                  int char_cells = utf_ptr2cells(orig_rt);
+                  if (used_cells + char_cells > ellipsis_width) {
+                    break;
+                  }
+                  used_cells += char_cells;
+                  MB_PTR_ADV(orig_rt);
+                  last_char = orig_rt;
+                }
+
+                if (last_char != NULL) {
+                  int over_cell = 0;
+                  if (used_cells < ellipsis_width) {
+                    over_cell = ellipsis_width - used_cells;
+                    MB_PTR_ADV(orig_rt);
+                    last_char = orig_rt;
+                  }
+                  size_t kept_len = strlen(last_char);
+                  char *new_str = xmalloc((size_t)ellipsis_width + (size_t)over_cell
+                                          + kept_len + 1);
+                  memset(new_str, '.', (size_t)ellipsis_width);
+                  if (over_cell > 0) {
+                    memset(new_str + ellipsis_width, ' ', (size_t)over_cell);
+                  }
+                  memcpy(new_str + ellipsis_width + over_cell, last_char, kept_len);
+                  new_str[(size_t)ellipsis_width + kept_len + (size_t)over_cell] = NUL;
+                  char *old_rt = rt_start;
+                  rt = rt_start = new_str;
+                  xfree(old_rt);
+                }
+              } else if (grid_col - cells > col_off - pum_width) {
                 // Most left character requires 2-cells but only 1 cell is available on
                 // screen.  Put a '<' on the left of the pum item.
                 *(--rt) = '<';
@@ -710,6 +770,53 @@ void pum_redraw(void)
             xfree(st);
             grid_col -= width;
           } else {
+            size_t size = strlen(st);
+            int cells = (int)mb_string2cells_len(st, size);
+            bool need_ellipsis = p_pmw > ellipsis_width
+                                 && pum_width == p_pmw
+                                 && grid_col + cells > col_off + pum_width;
+
+            // Add '...' indicator if truncated due to p_pmw
+            if (need_ellipsis) {
+              while (size > 0 && grid_col + cells > col_off + pum_width) {
+                size--;
+                size -= (size_t)utf_head_off(st, st + size);
+                cells -= utf_ptr2cells(st + size);
+              }
+              char *st_end = st + size;
+              int used_cells = 0;
+              char *last_char = NULL;
+              while (st_end > st) {
+                int char_cells = utf_ptr2cells(st_end);
+                if (used_cells + char_cells > ellipsis_width) {
+                  break;
+                }
+                used_cells += char_cells;
+                MB_PTR_BACK(st, st_end);
+                last_char = st_end;
+              }
+
+              if (last_char != NULL) {
+                int over_cell = 0;
+                if (used_cells < ellipsis_width) {
+                  MB_PTR_BACK(st, st_end);
+                  last_char = st_end;
+                  over_cell = ellipsis_width - used_cells;
+                }
+                size_t kept_len = (size_t)(last_char - st);
+                char *new_str = xmalloc((size_t)ellipsis_width + (size_t)over_cell
+                                        + kept_len + 1);
+                memcpy(new_str, st, kept_len);
+                if (over_cell > 0) {
+                  memset(new_str + kept_len, ' ', (size_t)over_cell);
+                }
+                memset(new_str + kept_len + over_cell, '.', (size_t)ellipsis_width);
+                new_str[kept_len + (size_t)ellipsis_width + (size_t)over_cell] = NUL;
+                xfree(st);
+                st = new_str;
+              }
+            }
+
             if (attrs == NULL) {
               grid_line_puts(grid_col, st, -1, attr);
             } else {
diff --git a/test/functional/ui/popupmenu_spec.lua b/test/functional/ui/popupmenu_spec.lua
index 0b7cff168b..7469269a1b 100644
--- a/test/functional/ui/popupmenu_spec.lua
+++ b/test/functional/ui/popupmenu_spec.lua
@@ -5478,7 +5478,289 @@ describe('builtin popupmenu', function()
       end
     end)
 
-    it('does not crash when displayed in the last column with rightleft #12032', function()
+    -- oldtest: Test_pum_maxwidth()
+    it('"pummaxwidth"', function()
+      screen:try_resize(60, 8)
+      api.nvim_buf_set_lines(0, 0, -1, true, {
+        '123456789_123456789_123456789_a',
+        '123456789_123456789_123456789_b',
+        '            123',
+      })
+      feed('G"zyy')
+      feed('A<C-X><C-N>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:------------------------------------------------------------]|*7
+          [3:------------------------------------------------------------]|
+        ## grid 2
+          123456789_123456789_123456789_a                             |
+          123456789_123456789_123456789_b                             |
+                      123456789_123456789_123456789_a^                 |
+          {1:~                                                           }|*4
+        ## grid 3
+          {2:-- Keyword Local completion (^N^P) }{5:match 1 of 2}             |
+        ## grid 4
+          {s: 123456789_123456789_123456789_a }|
+          {n: 123456789_123456789_123456789_b }|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 3, 11, false, 100 } },
+        })
+      else
+        screen:expect([[
+          123456789_123456789_123456789_a                             |
+          123456789_123456789_123456789_b                             |
+                      123456789_123456789_123456789_a^                 |
+          {1:~          }{s: 123456789_123456789_123456789_a }{1:                }|
+          {1:~          }{n: 123456789_123456789_123456789_b }{1:                }|
+          {1:~                                                           }|*2
+          {2:-- Keyword Local completion (^N^P) }{5:match 1 of 2}             |
+        ]])
+      end
+      feed('<Esc>3Gdd"zp')
+
+      command('set pummaxwidth=10')
+      feed('GA<C-X><C-N>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:------------------------------------------------------------]|*7
+          [3:------------------------------------------------------------]|
+        ## grid 2
+          123456789_123456789_123456789_a                             |
+          123456789_123456789_123456789_b                             |
+                      123456789_123456789_123456789_a^                 |
+          {1:~                                                           }|*4
+        ## grid 3
+          {2:-- Keyword Local completion (^N^P) }{5:match 1 of 2}             |
+        ## grid 4
+          {s: 1234567...}|
+          {n: 1234567...}|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 3, 11, false, 100 } },
+        })
+      else
+        screen:expect([[
+          123456789_123456789_123456789_a                             |
+          123456789_123456789_123456789_b                             |
+                      123456789_123456789_123456789_a^                 |
+          {1:~          }{s: 1234567...}{1:                                      }|
+          {1:~          }{n: 1234567...}{1:                                      }|
+          {1:~                                                           }|*2
+          {2:-- Keyword Local completion (^N^P) }{5:match 1 of 2}             |
+        ]])
+      end
+      feed('<Esc>3Gdd"zp')
+
+      command('set pummaxwidth=20')
+      feed('GA<C-X><C-N>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:------------------------------------------------------------]|*7
+          [3:------------------------------------------------------------]|
+        ## grid 2
+          123456789_123456789_123456789_a                             |
+          123456789_123456789_123456789_b                             |
+                      123456789_123456789_123456789_a^                 |
+          {1:~                                                           }|*4
+        ## grid 3
+          {2:-- Keyword Local completion (^N^P) }{5:match 1 of 2}             |
+        ## grid 4
+          {s: 123456789_1234567...}|
+          {n: 123456789_1234567...}|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 3, 11, false, 100 } },
+        })
+      else
+        screen:expect([[
+          123456789_123456789_123456789_a                             |
+          123456789_123456789_123456789_b                             |
+                      123456789_123456789_123456789_a^                 |
+          {1:~          }{s: 123456789_1234567...}{1:                            }|
+          {1:~          }{n: 123456789_1234567...}{1:                            }|
+          {1:~                                                           }|*2
+          {2:-- Keyword Local completion (^N^P) }{5:match 1 of 2}             |
+        ]])
+      end
+      feed('<Esc>3Gdd"zp')
+
+      command('set pumwidth=20 pummaxwidth=8')
+      feed('GA<C-X><C-N>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:------------------------------------------------------------]|*7
+          [3:------------------------------------------------------------]|
+        ## grid 2
+          123456789_123456789_123456789_a                             |
+          123456789_123456789_123456789_b                             |
+                      123456789_123456789_123456789_a^                 |
+          {1:~                                                           }|*4
+        ## grid 3
+          {2:-- Keyword Local completion (^N^P) }{5:match 1 of 2}             |
+        ## grid 4
+          {s: 12345...}|
+          {n: 12345...}|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 3, 11, false, 100 } },
+        })
+      else
+        screen:expect([[
+          123456789_123456789_123456789_a                             |
+          123456789_123456789_123456789_b                             |
+                      123456789_123456789_123456789_a^                 |
+          {1:~          }{s: 12345...}{1:                                        }|
+          {1:~          }{n: 12345...}{1:                                        }|
+          {1:~                                                           }|*2
+          {2:-- Keyword Local completion (^N^P) }{5:match 1 of 2}             |
+        ]])
+      end
+      feed('<Esc>3Gdd"zp')
+    end)
+
+    -- oldtest: Test_pum_maxwidth_multibyte()
+    it("'pummaxwidth' with multibyte", function()
+      screen:try_resize(60, 8)
+      exec([[
+        func Omni_test(findstart, base)
+          if a:findstart
+            return col(".")
+          endif
+          return [
+            \ #{word: "123456789_123456789_123456789_"},
+            \ #{word: "一二三四五六七八九十"},
+            \ ]
+        endfunc
+        set omnifunc=Omni_test
+      ]])
+
+      feed('S<C-X><C-O>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:------------------------------------------------------------]|*7
+          [3:------------------------------------------------------------]|
+        ## grid 2
+          123456789_123456789_123456789_^                              |
+          {1:~                                                           }|*6
+        ## grid 3
+          {2:-- Omni completion (^O^N^P) }{5:match 1 of 2}                    |
+        ## grid 4
+          {s:123456789_123456789_123456789_ }|
+          {n:一二三四五六七八九十           }|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 1, 0, false, 100 } },
+        })
+      else
+        screen:expect([[
+          123456789_123456789_123456789_^                              |
+          {s:123456789_123456789_123456789_ }{1:                             }|
+          {n:一二三四五六七八九十           }{1:                             }|
+          {1:~                                                           }|*4
+          {2:-- Omni completion (^O^N^P) }{5:match 1 of 2}                    |
+        ]])
+      end
+      feed('<Esc>')
+
+      command('set pummaxwidth=10')
+      feed('S<C-X><C-O>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:------------------------------------------------------------]|*7
+          [3:------------------------------------------------------------]|
+        ## grid 2
+          123456789_123456789_123456789_^                              |
+          {1:~                                                           }|*6
+        ## grid 3
+          {2:-- Omni completion (^O^N^P) }{5:match 1 of 2}                    |
+        ## grid 4
+          {s:1234567...}|
+          {n:一二三 ...}|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 1, 0, false, 100 } },
+        })
+      else
+        screen:expect([[
+          123456789_123456789_123456789_^                              |
+          {s:1234567...}{1:                                                  }|
+          {n:一二三 ...}{1:                                                  }|
+          {1:~                                                           }|*4
+          {2:-- Omni completion (^O^N^P) }{5:match 1 of 2}                    |
+        ]])
+      end
+      feed('<Esc>')
+
+      command('set rightleft')
+      feed('S<C-X><C-O>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:------------------------------------------------------------]|*7
+          [3:------------------------------------------------------------]|
+        ## grid 2
+                                       ^ _987654321_987654321_987654321|
+          {1:                                                           ~}|*6
+        ## grid 3
+          {2:-- Omni completion (^O^N^P) }{5:match 1 of 2}                    |
+        ## grid 4
+          {s:...7654321}|
+          {n:... 三二一}|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 1, 50, false, 100 } },
+        })
+      else
+        screen:expect([[
+                                       ^ _987654321_987654321_987654321|
+          {1:                                                  }{s:...7654321}|
+          {1:                                                  }{n:... 三二一}|
+          {1:                                                           ~}|*4
+          {2:-- Omni completion (^O^N^P) }{5:match 1 of 2}                    |
+        ]])
+      end
+      feed('<Esc>')
+      command('set norightleft')
+
+      command('set pummaxwidth=2')
+      feed('S<C-X><C-O>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:------------------------------------------------------------]|*7
+          [3:------------------------------------------------------------]|
+        ## grid 2
+          123456789_123456789_123456789_^                              |
+          {1:~                                                           }|*6
+        ## grid 3
+          {2:-- Omni completion (^O^N^P) }{5:match 1 of 2}                    |
+        ## grid 4
+          {s:12}|
+          {n:一}|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 1, 0, false, 100 } },
+        })
+      else
+        screen:expect([[
+          123456789_123456789_123456789_^                              |
+          {s:12}{1:                                                          }|
+          {n:一}{1:                                                          }|
+          {1:~                                                           }|*4
+          {2:-- Omni completion (^O^N^P) }{5:match 1 of 2}                    |
+        ]])
+      end
+      feed('<Esc>')
+    end)
+
+    it('does not crash when displayed in last column with rightleft #12032', function()
       local col = 30
       local items = { 'word', 'choice', 'text', 'thing' }
       local max_len = 0
diff --git a/test/old/testdir/test_popup.vim b/test/old/testdir/test_popup.vim
index 8f81db6213..631a81d5cc 100644
--- a/test/old/testdir/test_popup.vim
+++ b/test/old/testdir/test_popup.vim
@@ -1992,4 +1992,81 @@ func Test_pum_complete_with_special_characters()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_pum_maxwidth()
+  CheckScreendump
+
+  let lines =<< trim END
+    123456789_123456789_123456789_a
+    123456789_123456789_123456789_b
+                123
+  END
+  call writefile(lines, 'Xtest', 'D')
+  let buf = RunVimInTerminal('Xtest', {})
+
+  call term_sendkeys(buf, "G\"zyy")
+  call term_sendkeys(buf, "A\<C-N>")
+  call VerifyScreenDump(buf, 'Test_pum_maxwidth_01', {'rows': 8})
+  call term_sendkeys(buf, "\<Esc>3Gdd\"zp")
+
+  call term_sendkeys(buf, ":set pummaxwidth=10\<CR>")
+  call term_sendkeys(buf, "GA\<C-N>")
+  call VerifyScreenDump(buf, 'Test_pum_maxwidth_02', {'rows': 8})
+  call term_sendkeys(buf, "\<Esc>3Gdd\"zp")
+
+  call term_sendkeys(buf, ":set pummaxwidth=20\<CR>")
+  call term_sendkeys(buf, "GA\<C-N>")
+  call VerifyScreenDump(buf, 'Test_pum_maxwidth_03', {'rows': 8})
+  call term_sendkeys(buf, "\<Esc>3Gdd\"zp")
+
+  call term_sendkeys(buf, ":set pumwidth=20 pummaxwidth=8\<CR>")
+  call term_sendkeys(buf, "GA\<C-N>")
+  call VerifyScreenDump(buf, 'Test_pum_maxwidth_04', {'rows': 8})
+  call term_sendkeys(buf, "\<Esc>3Gdd\"zp")
+
+  call StopVimInTerminal(buf)
+endfunc
+
+func Test_pum_maxwidth_multibyte()
+  CheckScreendump
+
+  let lines =<< trim END
+    func Omni_test(findstart, base)
+      if a:findstart
+        return col(".")
+      endif
+      return [
+        \ #{word: "123456789_123456789_123456789_"},
+        \ #{word: "一二三四五六七八九十"},
+        \ ]
+    endfunc
+    set omnifunc=Omni_test
+  END
+  call writefile(lines, 'Xtest', 'D')
+  let  buf = RunVimInTerminal('-S Xtest', {})
+  call TermWait(buf)
+
+  call term_sendkeys(buf, "S\<C-X>\<C-O>")
+  call VerifyScreenDump(buf, 'Test_pum_maxwidth_05', {'rows': 8})
+  call term_sendkeys(buf, "\<ESC>")
+
+  call term_sendkeys(buf, ":set pummaxwidth=10\<CR>")
+  call term_sendkeys(buf, "S\<C-X>\<C-O>")
+  call VerifyScreenDump(buf, 'Test_pum_maxwidth_06', {'rows': 8})
+  call term_sendkeys(buf, "\<ESC>")
+
+  if has('rightleft')
+    call term_sendkeys(buf, ":set rightleft\<CR>")
+    call term_sendkeys(buf, "S\<C-X>\<C-O>")
+    call VerifyScreenDump(buf, 'Test_pum_maxwidth_07', {'rows': 8})
+    call term_sendkeys(buf, "\<Esc>:set norightleft\<CR>")
+  endif
+
+  call term_sendkeys(buf, ":set pummaxwidth=2\<CR>")
+  call term_sendkeys(buf, "S\<C-X>\<C-O>")
+  call VerifyScreenDump(buf, 'Test_pum_maxwidth_08', {'rows': 8})
+  call term_sendkeys(buf, "\<ESC>")
+
+  call StopVimInTerminal(buf)
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab