From: Father Chrysostomos <sprout@cpan.org>
Date: Mon, 14 Dec 2009 15:15:51 +0000 (+0100)
Subject: [perl #70171] 5.10.0 -> 5.10.1 Regression in fafafbaf70 (Big slowdown in 5.10 @_... 
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=0f907b96d618c97cd2e020841a70ae037954a616;p=p5sagit%2Fp5-mst-13.2.git

[perl #70171] 5.10.0 -> 5.10.1 Regression in fafafbaf70 (Big slowdown in 5.10 @_ parameter passing)

In this case my %x = %$x assigns a hash to itself. This causes the
hv_clear in pp_aassign to wipe away the hash before it can be copied.
The ‘panic: attempt to copy freed scalar’ error is triggered by this
line, which copies the value:
    sv_setsv(tmpstr,*relem);        /* value */

The solution is to make sure the OPpASSIGN_COMMON flag is on in such
cases, so that pp_aassign copies everything before doing the assignment.
---

diff --git a/op.c b/op.c
index bc8403a..19d7d5e 100644
--- a/op.c
+++ b/op.c
@@ -4277,7 +4277,7 @@ Perl_newASSIGNOP(pTHX_ I32 flags, OP *left, I32 optype, OP *right)
 		    || left->op_type == OP_PADHV
 		    || left->op_type == OP_PADANY))
 	{
-	    maybe_common_vars = FALSE;
+	    if (left->op_type == OP_PADSV) maybe_common_vars = FALSE;
 	    if (left->op_private & OPpPAD_STATE) {
 		/* All single variable list context state assignments, hence
 		   state ($a) = ...
diff --git a/t/op/array.t b/t/op/array.t
index 0027f4b..e36fd28 100644
--- a/t/op/array.t
+++ b/t/op/array.t
@@ -7,7 +7,7 @@ BEGIN {
 
 require 'test.pl';
 
-plan (125);
+plan (127);
 
 #
 # @foo, @bar, and @ary are also used from tie-stdarray after tie-ing them
@@ -428,5 +428,19 @@ sub test_arylen {
     is("$x $y $z", "1 1 2");
 }
 
+# [perl #70171]
+{
+ my $x = get_x(); my %x = %$x; sub get_x { %x=(1..4); return \%x };
+ is(
+   join(" ", map +($_,$x{$_}), sort keys %x), "1 2 3 4",
+  'bug 70171 (self-assignment via my %x = %$x)'
+ );
+ my $y = get_y(); my @y = @$y; sub get_y { @y=(1..4); return \@y };
+ is(
+  "@y", "1 2 3 4",
+  'bug 70171 (self-assignment via my @x = @$x)'
+ );
+}
+
 
 "We're included by lib/Tie/Array/std.t so we need to return something true";