From afeb2be6b58902f61e4857a7abe5442752564055 Mon Sep 17 00:00:00 2001
From: Kristoffer Carlsson <kcarlsson89@gmail.com>
Date: Fri, 25 Feb 2022 19:06:42 +0100
Subject: [PATCH] return immediately from `ht_keyindex` if dictionary is empty
 (#44341)

Avoids hashing the input key for empty dictionaries.

Inspired by rust-lang/hashbrown#305.
---
 base/dict.jl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/base/dict.jl b/base/dict.jl
index dabdfa5c347732..53f760999482f0 100644
--- a/base/dict.jl
+++ b/base/dict.jl
@@ -278,6 +278,7 @@ end
 
 # get the index where a key is stored, or -1 if not present
 function ht_keyindex(h::Dict{K,V}, key) where V where K
+    isempty(h) && return -1
     sz = length(h.keys)
     iter = 0
     maxprobe = h.maxprobe