From cf868c8eeb45f47063cc5d30b04b552e7dd5a7c4 Mon Sep 17 00:00:00 2001
From: "Roberto E. Vargas Caballero" <k0ga@shike2.com>
Date: Thu, 7 Jan 2016 12:34:40 +0100
Subject: [PATCH] Stop matching when lastmatch points to '\n'

This situation happens with something like s/$/test/,
where rm_so == rm_eo == 0. Without this check, ed
keeps looping forever.
---
 ed.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ed.c b/ed.c
index 67ffdb8..4a872ed 100644
--- a/ed.c
+++ b/ed.c
@@ -1005,7 +1005,7 @@ subline(int num, int nth)
 	static size_t siz, cap;
 
 	i = changed = siz = 0;
-	for (m = match(num); m; m = rematch(num)) {
+	for (m = match(num); m && *lastmatch != '\n'; m = rematch(num)) {
 		addpre(&s, &cap, &siz);
 		changed |= addsub(&s, &cap, &siz, nth, ++i);
 	}