fix(ui): apply 'pumborder' to mouse menu, fix overflow #36193

Problem:
Mouse popup menus (right-click context menus) do not respect the
'pumborder' option and could overflow screen boundaries when borders
were enabled near the edge.

Solution:
- Remove the mouse menu exclusion from border rendering.
- Add boundary check to shift menu left when border would exceed screen
  width, ensuring complete visibility of menu content and borders.

runtime/doc/options.txt

@@ -4903,6 +4903,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 	valid values. |hl-PmenuBorder| is used for highlighting the border, and when
 	style is "shadow" the |hl-PmenuShadow| and |hl-PmenuShadowThrough| groups are used.
 
+	This option also applies to mouse popup menus when 'mousemodel' is set to
+	"popup" or "popup_setpos", which will display borders using the same style.
+
 						*'pumheight'* *'ph'*
 'pumheight' 'ph'	number	(default 0)
 			global

runtime/lua/vim/_meta/options.lua

@@ -5108,6 +5108,9 @@ vim.go.pb = vim.go.pumblend
 --- valid values. `hl-PmenuBorder` is used for highlighting the border, and when
 --- style is "shadow" the `hl-PmenuShadow` and `hl-PmenuShadowThrough` groups are used.
 ---
+--- This option also applies to mouse popup menus when 'mousemodel' is set to
+--- "popup" or "popup_setpos", which will display borders using the same style.
+---
 --- @type string
 vim.o.pumborder = ""
 vim.go.pumborder = vim.o.pumborder

src/nvim/options.lua

@@ -6699,6 +6699,9 @@ local options = {
         Defines the default border style of popupmenu windows. See 'winborder' for
         valid values. |hl-PmenuBorder| is used for highlighting the border, and when
         style is "shadow" the |hl-PmenuShadow| and |hl-PmenuShadowThrough| groups are used.
+
+        This option also applies to mouse popup menus when 'mousemodel' is set to
+        "popup" or "popup_setpos", which will display borders using the same style.
       ]=],
       short_desc = N_('border of popupmenu'),
       type = 'string',

src/nvim/popupmenu.c

@@ -679,10 +679,7 @@ void pum_redraw(void)
   }
 
   int scroll_range = pum_size - pum_height;
-
+  if (fconfig.border) {
-  // avoid set border for mouse menu
-  int mouse_menu = State != MODE_CMDLINE && pum_grid.zindex == kZIndexCmdlinePopupMenu;
-  if (!mouse_menu && fconfig.border) {
     grid_draw_border(&pum_grid, &fconfig, NULL, 0, NULL);
     if (!fconfig.shadow) {
       row++;
@@ -1437,18 +1434,21 @@ static void pum_position_at_mouse(int min_width)
     pum_anchor_grid = grid;
   }
 
-  if (max_row - row > pum_size || max_row - row > row - min_row) {
+  // Both width and height are 1 for shadow border, otherwise 2
+  int border_width = pum_border_width();
+  int border_height = border_width;
+  if (max_row - row > pum_size + border_height || max_row - row > row - min_row) {
     // Enough space below the mouse row,
     // or there is more space below the mouse row than above.
     pum_above = false;
     pum_row = row + 1;
-    if (pum_height > max_row - pum_row) {
+    if (pum_height + border_height > max_row - pum_row) {
-      pum_height = max_row - pum_row;
+      pum_height = max_row - pum_row - border_height;
     }
   } else {
     // Show above the mouse row, reduce height if it does not fit.
     pum_above = true;
-    pum_row = row - pum_size;
+    pum_row = row - pum_size - border_height;
     if (pum_row < min_row) {
       pum_height += pum_row - min_row;
       pum_row = min_row;
@@ -1456,25 +1456,25 @@ static void pum_position_at_mouse(int min_width)
   }
 
   if (pum_rl) {
-    if (col - min_col + 1 >= pum_base_width
+    if (col - min_col + 1 >= pum_base_width + border_width
-        || col - min_col + 1 > min_width) {
+        || col - min_col + 1 > min_width + border_width) {
       // Enough space to show at mouse column.
       pum_col = col;
     } else {
       // Not enough space, left align with window.
-      pum_col = min_col + MIN(pum_base_width, min_width) - 1;
+      pum_col = min_col + MIN(pum_base_width + border_width, min_width + border_width) - 1;
     }
-    pum_width = pum_col - min_col + 1;
+    pum_width = pum_col - min_col + 1 - border_width;
   } else {
-    if (max_col - col >= pum_base_width
+    if (max_col - col >= pum_base_width + border_width
-        || max_col - col > min_width) {
+        || max_col - col > min_width + border_width) {
       // Enough space to show at mouse column.
       pum_col = col;
     } else {
       // Not enough space, right align with window.
-      pum_col = max_col - MIN(pum_base_width, min_width);
+      pum_col = max_col - MIN(pum_base_width + border_width, min_width + border_width);
     }
-    pum_width = max_col - pum_col;
+    pum_width = max_col - pum_col - border_width;
   }
 
   pum_width = MIN(pum_width, pum_base_width + 1);
@@ -1492,7 +1492,10 @@ static void pum_select_mouse_pos(void)
   }
 
   if (grid == pum_grid.handle) {
-    pum_selected = row;
+    // Offset by 1 when border width is 2 (non-shadow border)
+    int border_offset = pum_border_width() == 2 ? 1 : 0;
+    int item = row - border_offset;
+    pum_selected = (item >= 0 && item < pum_height) ? item : -1;
     return;
   }
 

test/functional/ui/popupmenu_spec.lua

@@ -9398,6 +9398,146 @@ describe('builtin popupmenu', function()
         end
       end)
     end)
+    it("'pumborder' on mouse-menu displays completely within screen", function()
+      screen:try_resize(40, 12)
+      command('set pumborder=rounded')
+      -- Click near right edge to test boundary handling
+      if send_mouse_grid then
+        api.nvim_input_mouse('right', 'press', '', 2, 2, 35)
+      else
+        feed('<RightMouse><35,2>')
+      end
+      if multigrid then
+        screen:expect({
+          grid = [[
+          ## grid 1
+            [2:----------------------------------------]|*11
+            [3:----------------------------------------]|
+          ## grid 2
+            ^                                        |
+            {1:~                                       }|*10
+          ## grid 3
+                                                    |
+          ## grid 4
+            {n:╭─────────────────────╮}|
+            {n:│ Inspect             │}|
+            {n:│                     │}|
+            {n:│ Paste               │}|
+            {n:│ Select All          │}|
+            {n:│                     │}|
+            {n:│ How-to disable mouse│}|
+            {n:╰─────────────────────╯}|
+          ]],
+          float_pos = {
+            [4] = { -1, 'NW', 2, 3, 17, false, 250, 2, 3, 17 },
+          },
+        })
+      else
+        screen:expect([[
+          ^                                        |
+          {1:~                                       }|*2
+          {1:~                }{n:╭─────────────────────╮}|
+          {1:~                }{n:│ Inspect             │}|
+          {1:~                }{n:│                     │}|
+          {1:~                }{n:│ Paste               │}|
+          {1:~                }{n:│ Select All          │}|
+          {1:~                }{n:│                     │}|
+          {1:~                }{n:│ How-to disable mouse│}|
+          {1:~                }{n:╰─────────────────────╯}|
+                                                  |
+        ]])
+      end
+      if send_mouse_grid then
+        api.nvim_input_mouse('move', '', '', 4, 1, 1)
+      else
+        feed('<MouseMove><25,4>')
+      end
+      if multigrid then
+        screen:expect({
+          grid = [[
+          ## grid 1
+            [2:----------------------------------------]|*11
+            [3:----------------------------------------]|
+          ## grid 2
+            ^                                        |
+            {1:~                                       }|*10
+          ## grid 3
+                                                    |
+          ## grid 4
+            {n:╭─────────────────────╮}|
+            {n:│}{12: Inspect             }{n:│}|
+            {n:│                     │}|
+            {n:│ Paste               │}|
+            {n:│ Select All          │}|
+            {n:│                     │}|
+            {n:│ How-to disable mouse│}|
+            {n:╰─────────────────────╯}|
+          ]],
+          float_pos = {
+            [4] = { -1, 'NW', 2, 3, 17, false, 250, 2, 3, 17 },
+          },
+        })
+      else
+        screen:expect([[
+          ^                                        |
+          {1:~                                       }|*2
+          {1:~                }{n:╭─────────────────────╮}|
+          {1:~                }{n:│}{12: Inspect             }{n:│}|
+          {1:~                }{n:│                     │}|
+          {1:~                }{n:│ Paste               │}|
+          {1:~                }{n:│ Select All          │}|
+          {1:~                }{n:│                     │}|
+          {1:~                }{n:│ How-to disable mouse│}|
+          {1:~                }{n:╰─────────────────────╯}|
+                                                  |
+        ]])
+      end
+      -- when right-clicking on the bottom menu, it should appear above the mouse_row
+      if send_mouse_grid then
+        api.nvim_input_mouse('right', 'press', '', 2, 8, 20)
+      else
+        feed('<RightMouse><20,8>')
+      end
+      if multigrid then
+        screen:expect({
+          grid = [[
+          ## grid 1
+            [2:----------------------------------------]|*11
+            [3:----------------------------------------]|
+          ## grid 2
+            ^                                        |
+            {1:~                                       }|*10
+          ## grid 3
+                                                    |
+          ## grid 4
+            {n:╭─────────────────────╮}|
+            {n:│ Inspect             │}|
+            {n:│                     │}|
+            {n:│ Paste               │}|
+            {n:│ Select All          │}|
+            {n:│                     │}|
+            {n:│ How-to disable mouse│}|
+            {n:╰─────────────────────╯}|
+          ]],
+          float_pos = {
+            [4] = { -1, 'SW', 2, 6, 17, false, 250, 2, 0, 17 },
+          },
+        })
+      else
+        screen:expect([[
+          ^                 {n:╭─────────────────────╮}|
+          {1:~                }{n:│ Inspect             │}|
+          {1:~                }{n:│                     │}|
+          {1:~                }{n:│ Paste               │}|
+          {1:~                }{n:│ Select All          │}|
+          {1:~                }{n:│                     │}|
+          {1:~                }{n:│ How-to disable mouse│}|
+          {1:~                }{n:╰─────────────────────╯}|
+          {1:~                                       }|*3
+                                                  |
+        ]])
+      end
+    end)
   end
 
   describe('with ext_multigrid and actual mouse grid', function()