[perl #18165] "0" fails as right-hand argument to ..

From: Mark-Jason Dominus (via RT) <perlbug@perl.org>
Message-Id: <rt-18165-40816.6.86096008382222@bugs6.perl.org>

(Fixed by making an exception for .."0" in pp_flop.)

p4raw-id: //depot/perl@18073

2 files changed, 11 insertions, 2 deletions

diff --git a/pp_ctl.c b/pp_ctl.c
index 07069cad4b..a482489f79 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -943,10 +943,15 @@ PP(pp_flop)
 	if (SvGMAGICAL(right))
 	    mg_get(right);
 
+	/* This code tries to decide if "$left .. $right" should use the
+	   magical string increment, or if the range is numeric (we make
+	   an exception for .."0" [#18165]). AMS 20021031. */
+
 	if (SvNIOKp(left) || !SvPOKp(left) ||
 	    SvNIOKp(right) || !SvPOKp(right) ||
 	    (looks_like_number(left) && *SvPVX(left) != '0' &&
-	     looks_like_number(right) && *SvPVX(right) != '0'))
+	     looks_like_number(right) && (*SvPVX(right) != '0' ||
+					  SvCUR(right) == 1)))
 	{
 	    if (SvNV(left) < IV_MIN || SvNV(right) > IV_MAX)
 		DIE(aTHX_ "Range iterator outside integer range");
diff --git a/t/op/range.t b/t/op/range.t
index e8aecf5fc9..862e64d103 100755
--- a/t/op/range.t
+++ b/t/op/range.t
@@ -1,6 +1,6 @@
 #!./perl
 
-print "1..15\n";
+print "1..16\n";
 
 print join(':',1..5) eq '1:2:3:4:5' ? "ok 1\n" : "not ok 1\n";
 
@@ -73,3 +73,7 @@ for my $x ("0"..-1) {
     print "not ";
 }
 print "ok 15\n";
+
+# [#18165] Should allow "-4".."0", broken by #4730. (AMS 20021031)
+print "not " unless 5 == (() = "-4".."0");
+print "ok 16\n";