From e3742f4217e46f42c4f0506c23b04b84fc31e7ad Mon Sep 17 00:00:00 2001
From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Sat, 18 Oct 2008 19:37:41 +0000
Subject: [PATCH] vi: explain why reading 4 chars is unsafe

---
 editors/vi.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/editors/vi.c b/editors/vi.c
index acbede359..8944f770a 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -2243,9 +2243,11 @@ static char readit(void)	// read (maybe cursor) key from stdin
 
 	n = chars_to_parse;
 	if (n == 0) {
-		// If no data, block waiting for input
-		// (can't read more than minimal ESC sequence -
-		// see "n = 0" below).
+		// If no data, block waiting for input.
+		// Can't read more than minimal ESC sequence size -
+		// see "n = 0" below. Example of mishandled
+		// sequence if we read 4 chars here: "ESC O A ESC O A".
+		// We'll read "ESC O A ESC" and lose second ESC!
 		n = safe_read(0, readbuffer, 3);
 		if (n <= 0) {
  error: