From cb146b945fb95e93bcc7c942d0eac4572a60f48f Mon Sep 17 00:00:00 2001
From: Anne van Kesteren <annevk@annevk.nl>
Date: Thu, 29 Dec 2016 16:02:19 +0100
Subject: [PATCH] IPv4 parser: handle the empty string

This is a theoretical issue once #185 lands, but as discussed it seems
good to address this anyway. Fixes #79.
---
 url.bs | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/url.bs b/url.bs
index 6696bd49..d65c67a3 100644
--- a/url.bs
+++ b/url.bs
@@ -464,8 +464,17 @@ runs these steps:
 
  <li><p>Let <var>parts</var> be <var>input</var> split on "<code>.</code>".
 
- <li><p>If the last item in <var>parts</var> is the empty string, set
- <var>syntaxViolationFlag</var> and remove the last item from <var>parts</var>.
+ <li>
+  <p>If the last item in <var>parts</var> is the empty string, then:
+
+  <ol>
+   <li><p>Set <var>syntaxViolationFlag</var>.
+
+   <li><p>If <var>parts</var> has more than one item, then remove the last item from
+   <var>parts</var>.
+   <!-- Since the IPv4 parser is not to be invoked directly the input cannot be the empty string,
+        but if it somehow is this conditional makes sure we can keep going. -->
+  </ol>
 
  <li><p>If <var>parts</var> has more than four items, return <var>input</var>.