From 045afa9e8a08ac11f7e306b1fa01fcf7214e8e8f Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Sun, 29 Sep 2024 18:38:17 +0800
Subject: [PATCH] fix(float): properly find last window of tabpage (#30571)

(cherry picked from commit df915f3afccb2717bc62e7b8649d76885cc3916c)
---
 src/nvim/winfloat.c               |  2 +-
 test/functional/ui/float_spec.lua | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/nvim/winfloat.c b/src/nvim/winfloat.c
index 331bbe5a3c..793f26cfb5 100644
--- a/src/nvim/winfloat.c
+++ b/src/nvim/winfloat.c
@@ -58,7 +58,7 @@ win_T *win_new_float(win_T *wp, bool last, WinConfig fconfig, Error *err)
       if (!tp) {
         return NULL;
       }
-      tp_last = tp->tp_lastwin;
+      tp_last = tp == curtab ? lastwin : tp->tp_lastwin;
       while (tp_last->w_floating && tp_last->w_prev) {
         tp_last = tp_last->w_prev;
       }
diff --git a/test/functional/ui/float_spec.lua b/test/functional/ui/float_spec.lua
index b20172eb09..f88d546752 100644
--- a/test/functional/ui/float_spec.lua
+++ b/test/functional/ui/float_spec.lua
@@ -662,6 +662,22 @@ describe('float window', function()
     screen:detach()
   end)
 
+  it('no crash with relative="win" after %bdelete #30569', function()
+    exec([[
+      botright vsplit
+      %bdelete
+    ]])
+    api.nvim_open_win(0, false, {
+      relative = 'win',
+      win = 0,
+      row = 0,
+      col = 5,
+      width = 5,
+      height = 5,
+    })
+    assert_alive()
+  end)
+
   describe('with only one tabpage,', function()
     local float_opts = {relative = 'editor', row = 1, col = 1, width = 1, height = 1}
     local old_buf, old_win