feat(ui): builtin ext_cmdline completion popupmenu

Problem:  Enabling ext_cmdline implicitly requires ext_popupmenu
          to handle cmdline-completion with wildoptions=pum.
Solution: Allow marking a window as the ext_cmdline window through
          nvim_open_win(), including prompt offset. Anchor the cmdline-
          completion popupmenu to this window. Projected to be used
          with a default ext_cmdline/message replacement.

runtime/doc/api.txt

@@ -3201,8 +3201,8 @@ nvim_open_win({buffer}, {enter}, {config})                   *nvim_open_win()*
                       like a tooltip near the buffer text).
                   • row: Row position in units of "screen cell height", may be
                     fractional.
-                  • col: Column position in units of "screen cell width", may
+                  • col: Column position in units of screen cell width, may be
-                    be fractional.
+                    fractional.
                   • focusable: Enable focus by user actions (wincmds, mouse
                     events). Defaults to true. Non-focusable windows can be
                     entered by |nvim_set_current_win()|, or, when the `mouse`
@@ -3292,6 +3292,9 @@ nvim_open_win({buffer}, {enter}, {config})                   *nvim_open_win()*
                   • hide: If true the floating window will be hidden.
                   • vertical: Split vertically |:vertical|.
                   • split: Split direction: "left", "right", "above", "below".
+                  • _cmdline_offset: (EXPERIMENTAL) When provided, anchor the
+                    |cmdline-completion| popupmenu to this window, with an
+                    offset in screen cell width.
 
     Return: ~
         Window handle, or 0 on error

runtime/lua/vim/_meta/api.lua

@@ -1771,8 +1771,7 @@ function vim.api.nvim_open_term(buffer, opts) end
 ---     - `row=0` and `col=0` if `anchor` is "SW" or "SE"
 ---       (thus like a tooltip near the buffer text).
 --- - row: Row position in units of "screen cell height", may be fractional.
---- - col: Column position in units of "screen cell width", may be
+--- - col: Column position in units of screen cell width, may be fractional.
----          fractional.
 --- - focusable: Enable focus by user actions (wincmds, mouse events).
 ---     Defaults to true. Non-focusable windows can be entered by
 ---     `nvim_set_current_win()`, or, when the `mouse` field is set to true,
@@ -1858,6 +1857,8 @@ function vim.api.nvim_open_term(buffer, opts) end
 --- - hide: If true the floating window will be hidden.
 --- - vertical: Split vertically `:vertical`.
 --- - split: Split direction: "left", "right", "above", "below".
+--- - _cmdline_offset: (EXPERIMENTAL) When provided, anchor the `cmdline-completion`
+---   popupmenu to this window, with an offset in screen cell width.
 --- @return integer # Window handle, or 0 on error
 function vim.api.nvim_open_win(buffer, enter, config) end
 

runtime/lua/vim/_meta/api_keysets.lua

@@ -307,6 +307,7 @@ error('Cannot require a meta file')
 --- @field noautocmd? boolean
 --- @field fixed? boolean
 --- @field hide? boolean
+--- @field _cmdline_offset? integer
 
 --- @class vim.api.keyset.win_text_height
 --- @field start_row? integer

src/nvim/api/keysets_defs.h

@@ -131,6 +131,7 @@ typedef struct {
   Boolean noautocmd;
   Boolean fixed;
   Boolean hide;
+  Integer _cmdline_offset;
 } Dict(win_config);
 
 typedef struct {

src/nvim/api/win_config.c

@@ -125,8 +125,7 @@
 ///       - `row=0` and `col=0` if `anchor` is "SW" or "SE"
 ///         (thus like a tooltip near the buffer text).
 ///   - row: Row position in units of "screen cell height", may be fractional.
-///   - col: Column position in units of "screen cell width", may be
+///   - col: Column position in units of screen cell width, may be fractional.
-///            fractional.
 ///   - focusable: Enable focus by user actions (wincmds, mouse events).
 ///       Defaults to true. Non-focusable windows can be entered by
 ///       |nvim_set_current_win()|, or, when the `mouse` field is set to true,
@@ -212,6 +211,8 @@
 ///   - hide: If true the floating window will be hidden.
 ///   - vertical: Split vertically |:vertical|.
 ///   - split: Split direction: "left", "right", "above", "below".
+///   - _cmdline_offset: (EXPERIMENTAL) When provided, anchor the |cmdline-completion|
+///     popupmenu to this window, with an offset in screen cell width.
 ///
 /// @param[out] err Error details, if any
 ///
@@ -295,6 +296,10 @@ Window nvim_open_win(Buffer buffer, Boolean enter, Dict(win_config) *config, Err
     goto cleanup;
   }
 
+  if (fconfig._cmdline_offset < INT_MAX) {
+    cmdline_win = wp;
+  }
+
   // Autocommands may close `wp` or move it to another tabpage, so update and check `tp` after each
   // event. In each case, `wp` should already be valid in `tp`, so switch_win should not fail.
   // Also, autocommands may free the `buf` to switch to, so store a bufref to check.
@@ -643,6 +648,11 @@ restore_curwin:
       didset_window_options(win, true);
     }
   }
+  if (fconfig._cmdline_offset < INT_MAX) {
+    cmdline_win = win;
+  } else if (win == cmdline_win && fconfig._cmdline_offset == INT_MAX) {
+    cmdline_win = NULL;
+  }
 #undef HAS_KEY_X
 }
 
@@ -773,6 +783,9 @@ Dict(win_config) nvim_win_get_config(Window window, Arena *arena, Error *err)
   const char *rel = (wp->w_floating && !config->external
                      ? float_relative_str[config->relative] : "");
   PUT_KEY_X(rv, relative, cstr_as_string(rel));
+  if (config->_cmdline_offset < INT_MAX) {
+    PUT_KEY_X(rv, _cmdline_offset, config->_cmdline_offset);
+  }
 
   return rv;
 }
@@ -1320,6 +1333,10 @@ static bool parse_win_config(win_T *wp, Dict(win_config) *config, WinConfig *fco
     fconfig->hide = config->hide;
   }
 
+  if (HAS_KEY_X(config, _cmdline_offset)) {
+    fconfig->_cmdline_offset = (int)config->_cmdline_offset;
+  }
+
   return true;
 
 fail:

src/nvim/buffer_defs.h

@@ -958,6 +958,7 @@ typedef struct {
   bool noautocmd;
   bool fixed;
   bool hide;
+  int _cmdline_offset;
 } WinConfig;
 
 #define WIN_CONFIG_INIT ((WinConfig){ .height = 0, .width = 0, \
@@ -971,7 +972,8 @@ typedef struct {
                                       .style = kWinStyleUnused, \
                                       .noautocmd = false, \
                                       .hide = false, \
-                                      .fixed = false })
+                                      .fixed = false, \
+                                      ._cmdline_offset = INT_MAX })
 
 // Structure to store last cursor position and topline.  Used by check_lnums()
 // and reset_lnums().

src/nvim/cmdexpand.c

@@ -365,7 +365,7 @@ static int cmdline_pum_create(CmdlineInfo *ccline, expand_T *xp, char **matches,
 
   // Compute the popup menu starting column
   char *endpos = showtail ? showmatches_gettail(xp->xp_pattern, true) : xp->xp_pattern;
-  if (ui_has(kUICmdline)) {
+  if (ui_has(kUICmdline) && cmdline_win == NULL) {
     compl_startcol = (int)(endpos - ccline->cmdbuff);
   } else {
     compl_startcol = cmd_screencol((int)(endpos - ccline->cmdbuff));
@@ -1067,13 +1067,10 @@ int showmatches(expand_T *xp, bool wildmenu)
     showtail = cmd_showtail;
   }
 
-  bool compl_use_pum = (ui_has(kUICmdline)
+  // Cmdline completion popup menu with ext_wildmenu, or wildoptions=pum and
-                        ? ui_has(kUIPopupmenu)
+  // no ext_cmdline, or ext_popupmenu, or cmdline_win set (_cmdline_offset).
-                        : wildmenu && (wop_flags & kOptWopFlagPum))
+  if (ui_has(kUIWildmenu) || ((!ui_has(kUICmdline) || ui_has(kUIPopupmenu) || cmdline_win != NULL)
-                       || ui_has(kUIWildmenu);
+                              && wildmenu && (wop_flags & kOptWopFlagPum))) {
-
-  if (compl_use_pum) {
-    // cmdline completion popup menu (with wildoptions=pum)
     return cmdline_pum_create(ccline, xp, matches, numMatches, showtail);
   }
 

src/nvim/ex_getln.c

@@ -2947,10 +2947,9 @@ static int cmd_startcol(void)
 int cmd_screencol(int bytepos)
 {
   int m;  // maximum column
-
   int col = cmd_startcol();
   if (KeyTyped) {
-    m = Columns * Rows;
+    m = cmdline_win ? cmdline_win->w_width_inner * cmdline_win->w_height_inner : Columns * Rows;
     if (m < 0) {        // overflow, Columns or Rows at weird value
       m = MAXCOL;
     }

src/nvim/globals.h

@@ -747,6 +747,7 @@ EXTERN int cmdwin_level INIT( = 0);   ///< cmdline recursion level
 EXTERN buf_T *cmdwin_buf INIT( = NULL);  ///< buffer of cmdline window or NULL
 EXTERN win_T *cmdwin_win INIT( = NULL);  ///< window of cmdline window or NULL
 EXTERN win_T *cmdwin_old_curwin INIT( = NULL);  ///< curwin before opening cmdline window or NULL
+EXTERN win_T *cmdline_win INIT( = NULL);  ///< window in use by ext_cmdline
 
 EXTERN char no_lines_msg[] INIT( = N_("--No lines in buffer--"));
 

src/nvim/popupmenu.c

@@ -154,11 +154,12 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
     validate_cursor_col(curwin);
     int above_row = 0;
     int below_row = cmdline_row;
-
+    win_T *target_win = (State == MODE_CMDLINE) ? cmdline_win : curwin;
     // wildoptions=pum
     if (State == MODE_CMDLINE) {
-      pum_win_row = ui_has(kUICmdline) ? 0 : cmdline_row;
+      pum_win_row = cmdline_win ? cmdline_win->w_wrow : ui_has(kUICmdline) ? 0 : cmdline_row;
-      cursor_col = cmd_startcol;
+      cursor_col = (cmdline_win ? cmdline_win->w_config._cmdline_offset : 0) + cmd_startcol;
+      cursor_col %= cmdline_win ? cmdline_win->w_width_inner : Columns;
       pum_anchor_grid = ui_has(kUICmdline) ? -1 : DEFAULT_GRID_HANDLE;
     } else {
       // anchor position: the start of the completed word
@@ -168,14 +169,16 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
       } else {
         cursor_col = curwin->w_wcol;
       }
-
       pum_anchor_grid = (int)curwin->w_grid.target->handle;
-      pum_win_row += curwin->w_grid.row_offset;
+    }
-      cursor_col += curwin->w_grid.col_offset;
+
-      if (!ui_has(kUIMultigrid) && curwin->w_grid.target != &default_grid) {
+    if (target_win != NULL) {
+      pum_win_row += target_win->w_grid.row_offset;
+      cursor_col += target_win->w_grid.col_offset;
+      if (!ui_has(kUIMultigrid) && target_win->w_grid.target != &default_grid) {
         pum_anchor_grid = (int)default_grid.handle;
-        pum_win_row += curwin->w_winrow;
+        pum_win_row += target_win->w_winrow;
-        cursor_col += curwin->w_wincol;
+        cursor_col += target_win->w_wincol;
       }
     }
 
@@ -221,16 +224,16 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
     int min_row = 0;
     int min_col = 0;
     int max_col = Columns;
-    int win_start_col = curwin->w_wincol;
+    int win_start_col = target_win ? target_win->w_wincol : 0;
-    int win_end_col = W_ENDCOL(curwin);
+    int win_end_col = target_win ? W_ENDCOL(target_win) : 0;
-    if (!(State & MODE_CMDLINE) && ui_has(kUIMultigrid)) {
+    if (target_win != NULL && ui_has(kUIMultigrid)) {
-      above_row -= curwin->w_winrow;
+      above_row -= target_win->w_winrow;
-      below_row = MAX(below_row - curwin->w_winrow, curwin->w_grid.rows);
+      below_row = MAX(below_row - target_win->w_winrow, target_win->w_grid.rows);
-      min_row = -curwin->w_winrow;
+      min_row = -target_win->w_winrow;
-      min_col = -curwin->w_wincol;
+      min_col = -target_win->w_wincol;
-      max_col = MAX(Columns - curwin->w_wincol, curwin->w_grid.cols);
+      max_col = MAX(Columns - target_win->w_wincol, target_win->w_grid.cols);
       win_start_col = 0;
-      win_end_col = curwin->w_grid.cols;
+      win_end_col = target_win->w_grid.cols;
     }
 
     // Figure out the size and position of the pum.
@@ -246,12 +249,12 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
       // pum above "pum_win_row"
       pum_above = true;
 
-      if (State == MODE_CMDLINE) {
+      if (State == MODE_CMDLINE && target_win == NULL) {
-        // for cmdline pum, no need for context lines
+        // For cmdline pum, no need for context lines unless target_win is set
         context_lines = 0;
       } else {
         // Leave two lines of context if possible
-        context_lines = MIN(2, curwin->w_wrow - curwin->w_cline_row);
+        context_lines = MIN(2, target_win->w_wrow - target_win->w_cline_row);
       }
 
       if (pum_win_row - min_row >= size + context_lines) {
@@ -270,14 +273,14 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed, i
       // pum below "pum_win_row"
       pum_above = false;
 
-      if (State == MODE_CMDLINE) {
+      if (State == MODE_CMDLINE && target_win == NULL) {
-        // for cmdline pum, no need for context lines
+        // for cmdline pum, no need for context lines unless target_win is set
         context_lines = 0;
       } else {
         // Leave two lines of context if possible
-        validate_cheight(curwin);
+        validate_cheight(target_win);
-        int cline_visible_offset = curwin->w_cline_row +
+        int cline_visible_offset = target_win->w_cline_row +
-                                   curwin->w_cline_height - curwin->w_wrow;
+                                   target_win->w_cline_height - target_win->w_wrow;
         context_lines = MIN(3, cline_visible_offset);
       }
 

test/functional/lua/ui_event_spec.lua

@@ -306,6 +306,100 @@ describe('vim.ui_attach', function()
       },
     })
   end)
+
+  it('ext_cmdline completion popupmenu', function()
+    screen:try_resize(screen._width, 10)
+    screen:add_extra_attr_ids { [100] = { background = Screen.colors.Black } }
+    exec_lua([[
+      vim.o.wildoptions = 'pum'
+      local buf = vim.api.nvim_create_buf(false, true)
+      vim.cmd('call setline(1, range(1, 10))')
+      _G.win = vim.api.nvim_open_win(buf, false, {
+        relative = 'editor',
+        col = 3,
+        row = 3,
+        width = 20,
+        height = 1,
+        style = 'minimal',
+        focusable = false,
+        zindex = 300,
+        _cmdline_offset = 0,
+      })
+      vim.ui_attach(ns, { ext_cmdline = true }, function(event, content, _, firstc)
+        if event == 'cmdline_show' then
+          local prompt = vim.api.nvim_win_get_config(_G.win)._cmdline_offset == 0
+          prompt = (prompt and firstc or 'Excommand:') .. content[1][2]
+          vim.api.nvim_buf_set_lines(buf, -2, -1, false, { prompt })
+          vim.api.nvim_win_set_cursor(_G.win, { 1, #prompt })
+          vim.api.nvim__redraw({ win = _G.win, cursor = true, flush = true })
+        end
+        return true
+      end)
+      vim.api.nvim_set_hl(0, 'Pmenu', {})
+    ]])
+    feed(':call buf<tab>')
+    screen:expect([[
+      1                                       |
+      2                                       |
+      3                                       |
+      4  :call bufadd^(                        |
+      5       {12: bufadd(         }{100: }              |
+      6        bufexists(      {100: }              |
+      7        buffer_exists(  {12: }              |
+      8        buffer_name(    {12: }              |
+      9        buffer_number(  {12: }              |
+                                              |
+    ]])
+    exec_lua([[
+      vim.api.nvim_win_set_config(_G.win, {
+        relative = 'editor',
+        col = 0,
+        row = 1000,
+        width = 1000,
+        height = 1,
+      })
+    ]])
+    screen:expect([[
+      1                                       |
+      2                                       |
+      3                                       |
+      4                                       |
+      5       {12: bufadd(         }{100: }              |
+      6        bufexists(      {100: }              |
+      7        buffer_exists(  {12: }              |
+      8        buffer_name(    {12: }              |
+      9        buffer_number(  {12: }              |
+      :call bufadd^(                           |
+    ]])
+    feed('<tab>')
+    screen:expect([[
+      1     bufadd(         {100: }                 |
+      2    {12: bufexists(      }{100: }                 |
+      3     buffer_exists(  {100: }                 |
+      4     buffer_name(    {100: }                 |
+      5     buffer_number(  {100: }                 |
+      6     buflisted(      {100: }                 |
+      7     bufload(        {12: }                 |
+      8     bufloaded(      {12: }                 |
+      9     bufname(        {12: }                 |
+      :call bufexists^(                        |
+    ]])
+    -- Test different offset (e.g. for custom prompt)
+    exec_lua('vim.api.nvim_win_set_config(_G.win, { _cmdline_offset = 9 })')
+    feed('<Esc>:call buf<Tab>')
+    screen:expect([[
+      1             {12: bufadd(         }{100: }        |
+      2              bufexists(      {100: }        |
+      3              buffer_exists(  {100: }        |
+      4              buffer_name(    {100: }        |
+      5              buffer_number(  {100: }        |
+      6              buflisted(      {100: }        |
+      7              bufload(        {12: }        |
+      8              bufloaded(      {12: }        |
+      9              bufname(        {12: }        |
+      Excommand:call bufadd^(                  |
+    ]])
+  end)
 end)
 
 describe('vim.ui_attach', function()

test/functional/ui/cmdline_spec.lua

@@ -623,8 +623,7 @@ local function test_cmdline(linegrid)
       { 'unplace', '', '', '' },
     }
 
-    command('set wildmode=full')
+    command('set wildmode=full wildmenu wildoptions=pum')
-    command('set wildmenu')
     screen:set_option('ext_popupmenu', true)
     feed(':sign <tab>')