fix(input): use click number of last click for mouse drag (#20300)

src/nvim/os/input.c

@@ -306,18 +306,13 @@ static uint8_t check_multiclick(int code, int grid, int row, int col)
   static int orig_mouse_row = 0;
   static uint64_t orig_mouse_time = 0;  // time of previous mouse click
 
-  if (code == KE_LEFTRELEASE
+  if ((code >= KE_MOUSEDOWN && code <= KE_MOUSERIGHT) || code == KE_MOUSEMOVE) {
-      || code == KE_RIGHTRELEASE
-      || code == KE_MIDDLERELEASE
-      || code == KE_MOUSEDOWN
-      || code == KE_MOUSEUP
-      || code == KE_MOUSELEFT
-      || code == KE_MOUSERIGHT
-      || code == KE_MOUSEMOVE) {
     return 0;
   }
-  uint64_t mouse_time = os_hrtime();    // time of current mouse click (ns)
 
+  // For click events the number of clicks is updated.
+  if (code == KE_LEFTMOUSE || code == KE_RIGHTMOUSE || code == KE_MIDDLEMOUSE) {
+    uint64_t mouse_time = os_hrtime();    // time of current mouse click (ns)
     // compute the time elapsed since the previous mouse click and
     // convert p_mouse from ms to ns
     uint64_t timediff = mouse_time - orig_mouse_time;
@@ -333,10 +328,13 @@ static uint8_t check_multiclick(int code, int grid, int row, int col)
       orig_num_clicks = 1;
     }
     orig_mouse_code = code;
+    orig_mouse_time = mouse_time;
+  }
+  // For drag and release events the number of clicks is kept.
+
   orig_mouse_grid = grid;
   orig_mouse_col = col;
   orig_mouse_row = row;
-  orig_mouse_time = mouse_time;
 
   uint8_t modifiers = 0;
   if (orig_num_clicks == 2) {

test/functional/ui/mouse_spec.lua

@@ -648,8 +648,10 @@ describe('ui/mouse/input', function()
     ]]}
   end)
 
-  it('two clicks will select the word and enter VISUAL', function()
+  it('two clicks will enter VISUAL and dragging selects words', function()
-    feed('<LeftMouse><2,2><LeftMouse><2,2>')
+    feed('<LeftMouse><2,2>')
+    feed('<LeftRelease><2,2>')
+    feed('<LeftMouse><2,2>')
     screen:expect([[
       testing                  |
       mouse                    |
@@ -657,10 +659,38 @@ describe('ui/mouse/input', function()
       {0:~                        }|
       {2:-- VISUAL --}             |
     ]])
+    feed('<LeftDrag><0,1>')
+    screen:expect([[
+      testing                  |
+      ^m{1:ouse}                    |
+      {1:support} and selection    |
+      {0:~                        }|
+      {2:-- VISUAL --}             |
+    ]])
+    feed('<LeftDrag><4,0>')
+    screen:expect([[
+      ^t{1:esting}                  |
+      {1:mouse}                    |
+      {1:support} and selection    |
+      {0:~                        }|
+      {2:-- VISUAL --}             |
+    ]])
+    feed('<LeftDrag><14,2>')
+    screen:expect([[
+      testing                  |
+      mouse                    |
+      {1:support and selectio}^n    |
+      {0:~                        }|
+      {2:-- VISUAL --}             |
+    ]])
   end)
 
-  it('three clicks will select the line and enter VISUAL LINE', function()
+  it('three clicks will enter VISUAL LINE and dragging selects lines', function()
-    feed('<LeftMouse><2,2><LeftMouse><2,2><LeftMouse><2,2>')
+    feed('<LeftMouse><2,2>')
+    feed('<LeftRelease><2,2>')
+    feed('<LeftMouse><2,2>')
+    feed('<LeftRelease><2,2>')
+    feed('<LeftMouse><2,2>')
     screen:expect([[
       testing                  |
       mouse                    |
@@ -668,10 +698,40 @@ describe('ui/mouse/input', function()
       {0:~                        }|
       {2:-- VISUAL LINE --}        |
     ]])
+    feed('<LeftDrag><0,1>')
+    screen:expect([[
+      testing                  |
+      ^m{1:ouse}                    |
+      {1:support and selection}    |
+      {0:~                        }|
+      {2:-- VISUAL LINE --}        |
+    ]])
+    feed('<LeftDrag><4,0>')
+    screen:expect([[
+      {1:test}^i{1:ng}                  |
+      {1:mouse}                    |
+      {1:support and selection}    |
+      {0:~                        }|
+      {2:-- VISUAL LINE --}        |
+    ]])
+    feed('<LeftDrag><14,2>')
+    screen:expect([[
+      testing                  |
+      mouse                    |
+      {1:support and se}^l{1:ection}    |
+      {0:~                        }|
+      {2:-- VISUAL LINE --}        |
+    ]])
   end)
 
-  it('four clicks will enter VISUAL BLOCK', function()
+  it('four clicks will enter VISUAL BLOCK and dragging selects blockwise', function()
-    feed('<LeftMouse><2,2><LeftMouse><2,2><LeftMouse><2,2><LeftMouse><2,2>')
+    feed('<LeftMouse><2,2>')
+    feed('<LeftRelease><2,2>')
+    feed('<LeftMouse><2,2>')
+    feed('<LeftRelease><2,2>')
+    feed('<LeftMouse><2,2>')
+    feed('<LeftRelease><2,2>')
+    feed('<LeftMouse><2,2>')
     screen:expect([[
       testing                  |
       mouse                    |
@@ -679,6 +739,30 @@ describe('ui/mouse/input', function()
       {0:~                        }|
       {2:-- VISUAL BLOCK --}       |
     ]])
+    feed('<LeftDrag><0,1>')
+    screen:expect([[
+      testing                  |
+      ^m{1:ou}se                    |
+      {1:sup}port and selection    |
+      {0:~                        }|
+      {2:-- VISUAL BLOCK --}       |
+    ]])
+    feed('<LeftDrag><4,0>')
+    screen:expect([[
+      te{1:st}^ing                  |
+      mo{1:use}                    |
+      su{1:ppo}rt and selection    |
+      {0:~                        }|
+      {2:-- VISUAL BLOCK --}       |
+    ]])
+    feed('<LeftDrag><14,2>')
+    screen:expect([[
+      testing                  |
+      mouse                    |
+      su{1:pport and se}^lection    |
+      {0:~                        }|
+      {2:-- VISUAL BLOCK --}       |
+    ]])
   end)
 
   it('right click extends visual selection to the clicked location', function()