From d1484b58ae877f1423f37092c7bfdacedccfb455 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Thu, 20 Oct 2022 22:05:51 +0800
Subject: vim-patch:9.0.0804: crash when trying to divide a number by -1

Problem:    Crash when trying to divice the largest negative number by -1.
Solution:   Handle this case specifically.
https://github.com/vim/vim/commit/cdef1cefa2a440911c727558562f83ed9b00e16b
---
 src/nvim/eval.c                | 4 ++++
 src/nvim/testdir/test_expr.vim | 6 ++++++
 2 files changed, 10 insertions(+)

(limited to 'src')

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index d9d276e8ea..245ad8d9d8 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -330,6 +330,10 @@ varnumber_T num_divide(varnumber_T n1, varnumber_T n2)
     } else {
       result = VARNUMBER_MAX;
     }
+  } else if (n1 == VARNUMBER_MIN && n2 == -1) {
+    // specific case: trying to do VARNUMBAR_MIN / -1 results in a positive
+    // number that doesn't fit in varnumber_T and causes an FPE
+    result = VARNUMBER_MAX;
   } else {
     result = n1 / n2;
   }
diff --git a/src/nvim/testdir/test_expr.vim b/src/nvim/testdir/test_expr.vim
index 8d3fb88541..c63a969e50 100644
--- a/src/nvim/testdir/test_expr.vim
+++ b/src/nvim/testdir/test_expr.vim
@@ -602,6 +602,12 @@ func Test_eval_after_if()
   call assert_equal('b', s:val)
 endfunc
 
+func Test_divide_by_zero()
+  " only tests that this doesn't crash, the result is not important
+  echo 0 / 0
+  echo 0 / 0 / -1
+endfunc
+
 " Test for command-line completion of expressions
 func Test_expr_completion()
   CheckFeature cmdline_compl
-- 
cgit