feat(tabline): middle mouse button now closes tab (#27522)

runtime/doc/news.txt

@@ -316,6 +316,8 @@ The following new APIs and features were added.
 
 • Added |nvim_tabpage_set_win()| to set the current window of a tabpage.
 
+• Clicking on a tabpage in the tabline with the middle mouse button closes it.
+
 ==============================================================================
 CHANGED FEATURES                                                 *news-changed*
 

src/nvim/mouse.c

@@ -136,6 +136,26 @@ static void move_tab_to_mouse(void)
     tabpage_move(tabnr);
   }
 }
+/// Close the current or specified tab page.
+///
+/// @param c1  tabpage number, or 999 for the current tabpage
+static void mouse_tab_close(int c1)
+{
+  tabpage_T *tp;
+
+  if (c1 == 999) {
+    tp = curtab;
+  } else {
+    tp = find_tabpage(c1);
+  }
+  if (tp == curtab) {
+    if (first_tabpage->tp_next != NULL) {
+      tabpage_close(false);
+    }
+  } else if (tp != NULL) {
+    tabpage_close_other(tp, false);
+  }
+}
 
 static bool got_click = false;  // got a click some time back
 
@@ -487,43 +507,32 @@ bool do_mouse(oparg_T *oap, int c, int dir, int count, bool fixindent)
       if (is_click && cmdwin_type == 0 && mouse_col < Columns) {
         in_tab_line = true;
         c1 = tab_page_click_defs[mouse_col].tabnr;
+
         switch (tab_page_click_defs[mouse_col].type) {
         case kStlClickDisabled:
           break;
-        case kStlClickTabClose: {
-          tabpage_T *tp;
-
-          // Close the current or specified tab page.
-          if (c1 == 999) {
-            tp = curtab;
-          } else {
-            tp = find_tabpage(c1);
-          }
-          if (tp == curtab) {
-            if (first_tabpage->tp_next != NULL) {
-              tabpage_close(false);
-            }
-          } else if (tp != NULL) {
-            tabpage_close_other(tp, false);
-          }
-          break;
-        }
         case kStlClickTabSwitch:
-          if ((mod_mask & MOD_MASK_MULTI_CLICK) == MOD_MASK_2CLICK) {
+          if (which_button != MOUSE_MIDDLE) {
-            // double click opens new page
+            if ((mod_mask & MOD_MASK_MULTI_CLICK) == MOD_MASK_2CLICK) {
-            end_visual_mode();
+              // double click opens new page
-            tabpage_new();
-            tabpage_move(c1 == 0 ? 9999 : c1 - 1);
-          } else {
-            // Go to specified tab page, or next one if not clicking
-            // on a label.
-            goto_tabpage(c1);
-
-            // It's like clicking on the status line of a window.
-            if (curwin != old_curwin) {
               end_visual_mode();
+              tabpage_new();
+              tabpage_move(c1 == 0 ? 9999 : c1 - 1);
+            } else {
+              // Go to specified tab page, or next one if not clicking
+              // on a label.
+              goto_tabpage(c1);
+
+              // It's like clicking on the status line of a window.
+              if (curwin != old_curwin) {
+                end_visual_mode();
+              }
             }
+            break;
           }
+          FALLTHROUGH;
+        case kStlClickTabClose:
+          mouse_tab_close(c1);
           break;
         case kStlClickFuncRun:
           call_click_def_func(tab_page_click_defs, mouse_col, which_button);

test/functional/ui/tabline_spec.lua

@@ -184,4 +184,18 @@ describe('tabline', function()
     ]],
     }
   end)
+
+  it('middle-click closes tab', function()
+    command('tabnew')
+    command('tabnew')
+    command('tabnew')
+    command('tabprev')
+    eq({ 3, 4 }, api.nvim_eval('[tabpagenr(), tabpagenr("$")]'))
+    api.nvim_input_mouse('middle', 'press', '', 0, 0, 1)
+    eq({ 2, 3 }, api.nvim_eval('[tabpagenr(), tabpagenr("$")]'))
+    api.nvim_input_mouse('middle', 'press', '', 0, 0, 20)
+    eq({ 2, 2 }, api.nvim_eval('[tabpagenr(), tabpagenr("$")]'))
+    api.nvim_input_mouse('middle', 'press', '', 0, 0, 1)
+    eq({ 1, 1 }, api.nvim_eval('[tabpagenr(), tabpagenr("$")]'))
+  end)
 end)