From 3ebfba7f5b10c4b14763d81a4aed5cdd3db2cea5 Mon Sep 17 00:00:00 2001
From: Mahmoud Al-Qudsi <mqudsi@neosmart.net>
Date: Sun, 25 Sep 2022 12:37:10 -0500
Subject: [PATCH] Test return builtin doesn't map negative numbers to zero

Prior to 1811a2d, the return value for negative return codes was UB and I'd
witnessed both expected cases like -256 mapping to a $status of 0 and unexpected
cases like a return value of -1 mapping to a $status of 0. As such, this doesn't
test just one fixed return value but the entire range from negative multiples of
256 all the way down (rather, up!) to -1.
---
 tests/checks/return.fish | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tests/checks/return.fish b/tests/checks/return.fish
index b63e336e4..9c2d7a4c5 100644
--- a/tests/checks/return.fish
+++ b/tests/checks/return.fish
@@ -20,3 +20,16 @@ $fish -ic 'echo interactive-foo; return 69; echo interactive-bar'
 # but not bar
 echo $status
 # CHECK: 69
+
+# Verify negative return values don't cause UB and never map to 0
+function empty_return
+    return $argv[1]
+end
+
+for i in (seq -550 -1)
+    empty_return $i
+    if test $status -eq 0
+        echo returning $i from a fish script maps to a $status of 0!
+    end
+end
+# CHECK: