From 0ca8573982f90699082c0b91af7798d0e41acbb7 Mon Sep 17 00:00:00 2001
From: rhysd <lin90162@yahoo.co.jp>
Date: Tue, 4 Oct 2022 17:25:32 +0900
Subject: [PATCH] fix panic when max history is zero (fix #4)

---
 src/history.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/history.rs b/src/history.rs
index 9c89a16..b27762e 100644
--- a/src/history.rs
+++ b/src/history.rs
@@ -110,9 +110,13 @@ impl History {
     }
 
     pub fn push(&mut self, edit: Edit) {
+        if self.max_items == 0 {
+            return;
+        }
+
         if self.edits.len() == self.max_items {
             self.edits.pop_front();
-            self.index -= 1;
+            self.index = self.index.saturating_sub(1);
         }
 
         if self.index < self.edits.len() {