From c8f85248c653c2ed4452f5de552ef3f50c4a1120 Mon Sep 17 00:00:00 2001
From: Father Chrysostomos <sprout@cpan.org>
Date: Sun, 22 Apr 2012 20:19:15 -0700
Subject: [PATCH] [perl #111794] Make goto "" like goto ${\""}
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

The logic was written in such a way that goto "" just happened to slip
past all the checks and cause pp_goto to return NULL for the next op,
which means the end of the program.

goto ${\""} dies with ‘goto must have label’, so goto ""
should as well.

This also adds other tests for that error, which was apparently
untested till now.
---
 pp_ctl.c    | 1 +
 t/op/goto.t | 9 ++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/pp_ctl.c b/pp_ctl.c
index 8f4c103..53f22f3 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -3056,6 +3056,7 @@ PP(pp_goto)
  	label       = cPVOP->op_pv;
         label_flags = (cPVOP->op_private & OPpPV_IS_UTF8) ? SVf_UTF8 : 0;
         label_len   = strlen(label);
+	if (!(do_dump || *label)) DIE(aTHX_ must_have_label);
     }
 
     PERL_ASYNC_CHECK();
diff --git a/t/op/goto.t b/t/op/goto.t
index cb9c6b6..f042f45 100644
--- a/t/op/goto.t
+++ b/t/op/goto.t
@@ -10,7 +10,7 @@ BEGIN {
 
 use warnings;
 use strict;
-plan tests => 80;
+plan tests => 83;
 our $TODO;
 
 my $deprecated = 0;
@@ -636,3 +636,10 @@ ok(
    same_prefix_labels(),
    "perl 112316: goto and labels with the same prefix doesn't get mixed up"
 );
+
+eval { my $x = ""; goto $x };
+like $@, qr/^goto must have label at /, 'goto $x where $x is empty string';
+eval { goto "" };
+like $@, qr/^goto must have label at /, 'goto ""';
+eval { goto };
+like $@, qr/^goto must have label at /, 'argless goto';
-- 
2.7.4