fix(float): fix crash with bufpos and non-existent window (#21319)

2 files changed, 17 insertions, 8 deletions

diff --git a/src/nvim/window.c b/src/nvim/window.c
index 86c936c734..1216bd8dcc 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -843,16 +843,16 @@ void win_config_float(win_T *wp, FloatConfig fconfig)
       grid_adjust(&grid, &row_off, &col_off);
       row += row_off;
       col += col_off;
+      if (wp->w_float_config.bufpos.lnum >= 0) {
+        pos_T pos = { wp->w_float_config.bufpos.lnum + 1,
+                      wp->w_float_config.bufpos.col, 0 };
+        int trow, tcol, tcolc, tcole;
+        textpos2screenpos(parent, &pos, &trow, &tcol, &tcolc, &tcole, true);
+        row += trow - 1;
+        col += tcol - 1;
+      }
     }
     api_clear_error(&dummy);
-    if (wp->w_float_config.bufpos.lnum >= 0) {
-      pos_T pos = { wp->w_float_config.bufpos.lnum + 1,
-                    wp->w_float_config.bufpos.col, 0 };
-      int trow, tcol, tcolc, tcole;
-      textpos2screenpos(parent, &pos, &trow, &tcol, &tcolc, &tcole, true);
-      row += trow - 1;
-      col += tcol - 1;
-    }
     wp->w_winrow = row;
     wp->w_wincol = col;
   } else {
diff --git a/test/functional/ui/float_spec.lua b/test/functional/ui/float_spec.lua
index dbf31ad753..bb09cfd504 100644
--- a/test/functional/ui/float_spec.lua
+++ b/test/functional/ui/float_spec.lua
@@ -391,6 +391,15 @@ describe('float window', function()
     eq(winids, eval('winids'))
   end)
 
+  it('no crash with bufpos and non-existent window', function()
+    command('new')
+    local closed_win = meths.get_current_win().id
+    command('close')
+    local buf = meths.create_buf(false,false)
+    meths.open_win(buf, true, {relative='win', win=closed_win, width=1, height=1, bufpos={0,0}})
+    assert_alive()
+  end)
+
   it("no segfault when setting minimal style after clearing local 'fillchars' #19510", function()
     local float_opts = {relative = 'editor', row = 1, col = 1, width = 1, height = 1}
     local float_win = meths.open_win(0, true, float_opts)