feat(float): allow enabling mouse for non-focusable window (#30844)

Problem:  Cannot allow mouse interaction for non-focusable float window.
Solution: Add a "mouse" field to float window config.

16 files changed, 70 insertions, 21 deletions

diff --git a/runtime/doc/api.txt b/runtime/doc/api.txt
index dee0324a5b..c77f38a693 100644
--- a/runtime/doc/api.txt
+++ b/runtime/doc/api.txt
@@ -3195,7 +3195,13 @@ nvim_open_win({buffer}, {enter}, {config})                   *nvim_open_win()*
                     be fractional.
                   • focusable: Enable focus by user actions (wincmds, mouse
                     events). Defaults to true. Non-focusable windows can be
-                    entered by |nvim_set_current_win()|.
+                    entered by |nvim_set_current_win()|, or, when the `mouse`
+                    field is set to true, by mouse events.
+                  • mouse: Specify how this window interacts with mouse
+                    events. Defaults to `focusable` value.
+                    • If false, mouse events pass through this window.
+                    • If true, mouse events interact with this window
+                      normally.
                   • external: GUI should display the window as an external
                     top-level window. Currently accepts no other positioning
                     configuration together with this.
diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
index def66a0773..56104d9fdb 100644
--- a/runtime/doc/news.txt
+++ b/runtime/doc/news.txt
@@ -40,6 +40,8 @@ API
   This is not expected to break clients because there are no known clients
   that actually use the `return_type` field or the parameter type names
   reported by |--api-info| or |nvim_get_api_info()|.
+• |nvim_open_win()| supports a `mouse` field that allows configuring mouse
+  interaction with the window separately from `focusable` field.
 • Renamed `nvim__id_dictionary` (unsupported/experimental API) to
   `nvim__id_dict`.
 
diff --git a/runtime/doc/ui.txt b/runtime/doc/ui.txt
index d37cdfb9df..cb057a8fd2 100644
--- a/runtime/doc/ui.txt
+++ b/runtime/doc/ui.txt
@@ -610,11 +610,12 @@ tabs.
 	size). If the window was previously hidden, it should now be shown
 	again.
 
-["win_float_pos", grid, win, anchor, anchor_grid, anchor_row, anchor_col, focusable, zindex] ~
+["win_float_pos", grid, win, anchor, anchor_grid, anchor_row, anchor_col, mouse_enabled, zindex] ~
 	Display or reconfigure floating window `win`. The window should be
 	displayed above another grid `anchor_grid` at the specified position
-	`anchor_row` and `anchor_col`. For the meaning of `anchor` and more
-	details of positioning, see |nvim_open_win()|.
+	`anchor_row` and `anchor_col`. For the meaning of `anchor` and more details
+	of positioning, see |nvim_open_win()|. `mouse_enabled` is true if the
+	window can receive mouse events.
 
 ["win_external_pos", grid, win] ~
 	Display or reconfigure external window `win`. The window should be
diff --git a/runtime/lua/vim/_meta/api.lua b/runtime/lua/vim/_meta/api.lua
index c66b295d3a..8236cc7cf0 100644
--- a/runtime/lua/vim/_meta/api.lua
+++ b/runtime/lua/vim/_meta/api.lua
@@ -1767,7 +1767,12 @@ function vim.api.nvim_open_term(buffer, opts) end
 ---          fractional.
 --- - focusable: Enable focus by user actions (wincmds, mouse events).
 ---     Defaults to true. Non-focusable windows can be entered by
----     `nvim_set_current_win()`.
+---     `nvim_set_current_win()`, or, when the `mouse` field is set to true,
+---     by mouse events.
+--- - mouse: Specify how this window interacts with mouse events.
+---     Defaults to `focusable` value.
+---     - If false, mouse events pass through this window.
+---     - If true, mouse events interact with this window normally.
 --- - external: GUI should display the window as an external
 ---     top-level window. Currently accepts no other positioning
 ---     configuration together with this.
diff --git a/runtime/lua/vim/_meta/api_keysets.lua b/runtime/lua/vim/_meta/api_keysets.lua
index 2fe5c32faf..bf184dee2d 100644
--- a/runtime/lua/vim/_meta/api_keysets.lua
+++ b/runtime/lua/vim/_meta/api_keysets.lua
@@ -295,6 +295,7 @@ error('Cannot require a meta file')
 --- @field bufpos? any[]
 --- @field external? boolean
 --- @field focusable? boolean
+--- @field mouse? boolean
 --- @field vertical? boolean
 --- @field zindex? integer
 --- @field border? any
diff --git a/src/nvim/api/keysets_defs.h b/src/nvim/api/keysets_defs.h
index 552612dd13..96aabb851f 100644
--- a/src/nvim/api/keysets_defs.h
+++ b/src/nvim/api/keysets_defs.h
@@ -119,6 +119,7 @@ typedef struct {
   Array bufpos;
   Boolean external;
   Boolean focusable;
+  Boolean mouse;
   Boolean vertical;
   Integer zindex;
   Object border;
diff --git a/src/nvim/api/ui_events.in.h b/src/nvim/api/ui_events.in.h
index 2bd8792d71..865e84ab91 100644
--- a/src/nvim/api/ui_events.in.h
+++ b/src/nvim/api/ui_events.in.h
@@ -102,7 +102,7 @@ void win_pos(Integer grid, Window win, Integer startrow, Integer startcol, Integ
              Integer height)
   FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY;
 void win_float_pos(Integer grid, Window win, String anchor, Integer anchor_grid, Float anchor_row,
-                   Float anchor_col, Boolean focusable, Integer zindex)
+                   Float anchor_col, Boolean mouse_enabled, Integer zindex)
   FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY;
 void win_external_pos(Integer grid, Window win)
   FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY;
diff --git a/src/nvim/api/win_config.c b/src/nvim/api/win_config.c
index f63fdc5381..16811e0cd9 100644
--- a/src/nvim/api/win_config.c
+++ b/src/nvim/api/win_config.c
@@ -129,7 +129,12 @@
 ///            fractional.
 ///   - focusable: Enable focus by user actions (wincmds, mouse events).
 ///       Defaults to true. Non-focusable windows can be entered by
-///       |nvim_set_current_win()|.
+///       |nvim_set_current_win()|, or, when the `mouse` field is set to true,
+///       by mouse events.
+///   - mouse: Specify how this window interacts with mouse events.
+///       Defaults to `focusable` value.
+///       - If false, mouse events pass through this window.
+///       - If true, mouse events interact with this window normally.
 ///   - external: GUI should display the window as an external
 ///       top-level window. Currently accepts no other positioning
 ///       configuration together with this.
@@ -714,6 +719,7 @@ Dict(win_config) nvim_win_get_config(Window window, Arena *arena, Error *err)
   PUT_KEY_X(rv, focusable, config->focusable);
   PUT_KEY_X(rv, external, config->external);
   PUT_KEY_X(rv, hide, config->hide);
+  PUT_KEY_X(rv, mouse, config->mouse);
 
   if (wp->w_floating) {
     PUT_KEY_X(rv, width, config->width);
@@ -1202,6 +1208,11 @@ static bool parse_win_config(win_T *wp, Dict(win_config) *config, WinConfig *fco
 
   if (HAS_KEY_X(config, focusable)) {
     fconfig->focusable = config->focusable;
+    fconfig->mouse = config->focusable;
+  }
+
+  if (HAS_KEY_X(config, mouse)) {
+    fconfig->mouse = config->mouse;
   }
 
   if (HAS_KEY_X(config, zindex)) {
diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index 6f059fc376..1fe5512708 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -938,6 +938,7 @@ typedef struct {
   FloatRelative relative;
   bool external;
   bool focusable;
+  bool mouse;
   WinSplit split;
   int zindex;
   WinStyle style;
@@ -964,6 +965,7 @@ typedef struct {
                                       .row = 0, .col = 0, .anchor = 0, \
                                       .relative = 0, .external = false, \
                                       .focusable = true, \
+                                      .mouse = true, \
                                       .split = 0, \
                                       .zindex = kZIndexFloatDefault, \
                                       .style = kWinStyleUnused, \
diff --git a/src/nvim/grid_defs.h b/src/nvim/grid_defs.h
index ac67f42fe0..19a79ff810 100644
--- a/src/nvim/grid_defs.h
+++ b/src/nvim/grid_defs.h
@@ -80,8 +80,8 @@ struct ScreenGrid {
   // whether the compositor should blend the grid with the background grid
   bool blending;
 
-  // whether the grid can be focused with mouse clicks.
-  bool focusable;
+  // whether the grid interacts with mouse events.
+  bool mouse_enabled;
 
   // z-index: the order in the stack of grids.
   int zindex;
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 79e6bc8be7..151fb3d903 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -199,7 +199,7 @@ void msg_grid_validate(void)
     ui_call_grid_resize(msg_grid.handle, msg_grid.cols, msg_grid.rows);
 
     msg_scrolled_at_flush = msg_scrolled;
-    msg_grid.focusable = false;
+    msg_grid.mouse_enabled = false;
     msg_grid_adj.target = &msg_grid;
   } else if (!should_alloc && msg_grid.chars) {
     ui_comp_remove_grid(&msg_grid);
diff --git a/src/nvim/mouse.c b/src/nvim/mouse.c
index 884bc88d73..1289adfabb 100644
--- a/src/nvim/mouse.c
+++ b/src/nvim/mouse.c
@@ -1740,7 +1740,7 @@ static win_T *mouse_find_grid_win(int *gridp, int *rowp, int *colp)
   } else if (*gridp > 1) {
     win_T *wp = get_win_by_grid_handle(*gridp);
     if (wp && wp->w_grid_alloc.chars
-        && !(wp->w_floating && !wp->w_config.focusable)) {
+        && !(wp->w_floating && !wp->w_config.mouse)) {
       *rowp = MIN(*rowp - wp->w_grid.row_offset, wp->w_grid.rows - 1);
       *colp = MIN(*colp - wp->w_grid.col_offset, wp->w_grid.cols - 1);
       return wp;
diff --git a/src/nvim/ui_compositor.c b/src/nvim/ui_compositor.c
index 6e89894e0b..e28e8d4da7 100644
--- a/src/nvim/ui_compositor.c
+++ b/src/nvim/ui_compositor.c
@@ -275,7 +275,7 @@ ScreenGrid *ui_comp_mouse_focus(int row, int col)
 {
   for (ssize_t i = (ssize_t)kv_size(layers) - 1; i > 0; i--) {
     ScreenGrid *grid = kv_A(layers, i);
-    if (grid->focusable
+    if (grid->mouse_enabled
         && row >= grid->comp_row && row < grid->comp_row + grid->rows
         && col >= grid->comp_col && col < grid->comp_col + grid->cols) {
       return grid;
diff --git a/src/nvim/window.c b/src/nvim/window.c
index d3280a3478..91a69c3ec4 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -857,7 +857,7 @@ void ui_ext_win_position(win_T *wp, bool validate)
       String anchor = cstr_as_string(float_anchor_str[c.anchor]);
       if (!c.hide) {
         ui_call_win_float_pos(wp->w_grid_alloc.handle, wp->handle, anchor,
-                              grid->handle, row, col, c.focusable,
+                              grid->handle, row, col, c.mouse,
                               wp->w_grid_alloc.zindex);
       } else {
         ui_call_win_hide(wp->w_grid_alloc.handle);
@@ -889,7 +889,7 @@ void ui_ext_win_position(win_T *wp, bool validate)
         ui_comp_put_grid(&wp->w_grid_alloc, comp_row, comp_col,
                          wp->w_height_outer, wp->w_width_outer, valid, false);
         ui_check_cursor_grid(wp->w_grid_alloc.handle);
-        wp->w_grid_alloc.focusable = wp->w_config.focusable;
+        wp->w_grid_alloc.mouse_enabled = wp->w_config.mouse;
         if (!valid) {
           wp->w_grid_alloc.valid = false;
           redraw_later(wp, UPD_NOT_VALID);
@@ -4044,6 +4044,7 @@ void win_alloc_aucmd_win(int idx)
   fconfig.width = Columns;
   fconfig.height = 5;
   fconfig.focusable = false;
+  fconfig.mouse = false;
   aucmd_win[idx].auc_win = win_new_float(NULL, true, fconfig, &err);
   aucmd_win[idx].auc_win->w_buffer->b_nwindows--;
   RESET_BINDING(aucmd_win[idx].auc_win);
diff --git a/src/nvim/winfloat.c b/src/nvim/winfloat.c
index fdb65ad614..054ef07fc5 100644
--- a/src/nvim/winfloat.c
+++ b/src/nvim/winfloat.c
@@ -389,6 +389,7 @@ win_T *win_float_create(bool enter, bool new_buf)
   config.row = curwin->w_wrow;
   config.relative = kFloatRelativeEditor;
   config.focusable = false;
+  config.mouse = false;
   config.anchor = 0;  // NW
   config.noautocmd = true;
   config.hide = true;
diff --git a/test/functional/ui/float_spec.lua b/test/functional/ui/float_spec.lua
index 9b77cb4014..b76474fd58 100644
--- a/test/functional/ui/float_spec.lua
+++ b/test/functional/ui/float_spec.lua
@@ -1278,7 +1278,7 @@ describe('float window', function()
     it('return their configuration', function()
       local buf = api.nvim_create_buf(false, false)
       local win = api.nvim_open_win(buf, false, {relative='editor', width=20, height=2, row=3, col=5, zindex=60})
-      local expected = {anchor='NW', col=5, external=false, focusable=true, height=2, relative='editor', row=3, width=20, zindex=60, hide=false}
+      local expected = {anchor='NW', col=5, external=false, focusable=true, mouse=true, height=2, relative='editor', row=3, width=20, zindex=60, hide=false}
       eq(expected, api.nvim_win_get_config(win))
       eq(true, exec_lua([[
         local expected, win = ...
@@ -1290,11 +1290,11 @@ describe('float window', function()
         end
         return true]], expected, win))
 
-      eq({external=false, focusable=true, hide=false, relative='',split="left",width=40,height=6}, api.nvim_win_get_config(0))
+      eq({external=false, focusable=true, mouse=true, hide=false, relative='',split="left",width=40,height=6}, api.nvim_win_get_config(0))
 
       if multigrid then
         api.nvim_win_set_config(win, {external=true, width=10, height=1})
-        eq({external=true,focusable=true,width=10,height=1,relative='',hide=false}, api.nvim_win_get_config(win))
+        eq({external=true,focusable=true,mouse=true,width=10,height=1,relative='',hide=false}, api.nvim_win_get_config(win))
       end
     end)
 
@@ -3988,7 +3988,7 @@ describe('float window', function()
         ]]}
       end
       eq({relative='win', width=12, height=1, bufpos={1,32}, anchor='NW', hide=false,
-          external=false, col=0, row=1, win=firstwin, focusable=true, zindex=50}, api.nvim_win_get_config(win))
+          external=false, col=0, row=1, win=firstwin, focusable=true, mouse=true, zindex=50}, api.nvim_win_get_config(win))
 
       feed('<c-e>')
       if multigrid then
@@ -5606,7 +5606,7 @@ describe('float window', function()
         end
       end)
 
-      it("focus by mouse", function()
+      local function test_float_mouse_focus()
         if multigrid then
           api.nvim_input_mouse('left', 'press', '', 4, 0, 0)
           screen:expect{grid=[[
@@ -5660,10 +5660,18 @@ describe('float window', function()
                                                     |
           ]])
         end
+      end
+
+      it("focus by mouse (focusable=true)", function()
+        test_float_mouse_focus()
       end)
 
-      it("focus by mouse (focusable=false)", function()
-        api.nvim_win_set_config(win, {focusable=false})
+      it("focus by mouse (focusable=false, mouse=true)", function()
+        api.nvim_win_set_config(win, {focusable=false, mouse=true})
+        test_float_mouse_focus()
+      end)
+
+      local function test_float_mouse_no_focus()
         api.nvim_buf_set_lines(0, -1, -1, true, {"a"})
         expected_pos[4][6] = false
         if multigrid then
@@ -5721,6 +5729,16 @@ describe('float window', function()
                                                     |
           ]])
         end
+      end
+
+      it("focus by mouse (focusable=false)", function()
+        api.nvim_win_set_config(win, {focusable=false})
+        test_float_mouse_no_focus()
+      end)
+
+      it("focus by mouse (focusable=true, mouse=false)", function()
+        api.nvim_win_set_config(win, {mouse=false})
+        test_float_mouse_no_focus()
       end)
 
       it("j", function()