From c96b292a824e81a7d9af266ae18a0ed304be343f Mon Sep 17 00:00:00 2001
From: "A. R. Shajii" <ars@ars.me>
Date: Tue, 4 Jul 2023 23:52:10 -0400
Subject: [PATCH] Fix str.zfill() on empty string

---
 stdlib/internal/str.codon | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stdlib/internal/str.codon b/stdlib/internal/str.codon
index d10146b7..274da890 100644
--- a/stdlib/internal/str.codon
+++ b/stdlib/internal/str.codon
@@ -591,7 +591,7 @@ class str:
         fill = width - len(self)
         p = zf.ptr
 
-        if p[fill] == plus or p[fill] == minus:
+        if len(self) > 0 and p[fill] == plus or p[fill] == minus:
             p[0] = p[fill]
             p[fill] = zero