From 0706c55ab1bc9a8987b18cd25ceb509801a71038 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Sat, 6 Dec 2025 21:49:16 +0800
Subject: [PATCH] vim-patch:partial:9.1.1955: sort() does not handle large
 numbers correctly (#36840)

Problem:  sort() does not handle large numbers correctly
          (Igbanam Ogbuluijah)
Solution: Don't truncate the return value of tv_get_number_chk()
          (Yegappan Lakshmanan)

closes: vim/vim#18868

https://github.com/vim/vim/commit/04794efe12863eb96a489531c299879e6c8d15d4

Use a Lua test for now, as the Vimscript test uses tuples.

Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
(cherry picked from commit 5370b7a2e0a0484c9005cb5a727dffa5ef13b1ed)
---
 src/nvim/eval/typval.c                  |  8 ++------
 test/functional/vimscript/sort_spec.lua | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index f9cf245e50..f2cf23bc15 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -1287,12 +1287,8 @@ static int item_compare2(const void *s1, const void *s2, bool keep_zero)
     res = ITEM_COMPARE_FAIL;
     sortinfo->item_compare_func_err = true;
   } else {
-    res = (int)tv_get_number_chk(&rettv, &sortinfo->item_compare_func_err);
-    if (res > 0) {
-      res = 1;
-    } else if (res < 0) {
-      res = -1;
-    }
+    varnumber_T n = tv_get_number_chk(&rettv, &sortinfo->item_compare_func_err);
+    res = (n > 0) ? 1 : (n < 0) ? -1 : 0;
   }
   if (sortinfo->item_compare_func_err) {
     res = ITEM_COMPARE_FAIL;  // return value has wrong type
diff --git a/test/functional/vimscript/sort_spec.lua b/test/functional/vimscript/sort_spec.lua
index c99a6ebadd..c52d705393 100644
--- a/test/functional/vimscript/sort_spec.lua
+++ b/test/functional/vimscript/sort_spec.lua
@@ -66,4 +66,29 @@ describe('sort()', function()
       pcall_err(command, 'let sl = sort([1, 0, [], 3, 2], "Cmp")')
     )
   end)
+
+  it('handles large numbers properly', function()
+    local to_sort = {
+      { 229539777187355, 229539777187355 },
+      { 487766135067138, 491977135306566 },
+      { 188325333471071, 188931909913550 },
+      { 264028451845520, 265514296554744 },
+      { 245727634348687, 249469249579525 },
+      { 375117820166731, 378942174241518 },
+      { 535474757750378, 535849288071548 },
+    }
+    local expected = {
+      { 188325333471071, 188931909913550 },
+      { 229539777187355, 229539777187355 },
+      { 245727634348687, 249469249579525 },
+      { 264028451845520, 265514296554744 },
+      { 375117820166731, 378942174241518 },
+      { 487766135067138, 491977135306566 },
+      { 535474757750378, 535849288071548 },
+    }
+    eq(expected, fn.sort(to_sort))
+    api.nvim_set_var('to_sort', to_sort)
+    eq(expected, api.nvim_eval('sort(g:to_sort)'))
+    eq(expected, api.nvim_eval('sort(g:to_sort, {a, b -> a[0] - b[0]})'))
+  end)
 end)