A new try from Dave Mitchell for [perl #23265].

p4raw-id: //depot/perl@20631

2 files changed, 36 insertions, 5 deletions

diff --git a/pad.c b/pad.c
index 90d99795a5..06f0417f16 100644
--- a/pad.c
+++ b/pad.c
@@ -257,11 +257,19 @@ Perl_pad_undef(pTHX_ CV* cv)
 		    && CvOUTSIDE(innercv) == cv)
 		{
 		    assert(CvWEAKOUTSIDE(innercv));
-		    CvWEAKOUTSIDE_off(innercv);
-		    CvOUTSIDE(innercv) = outercv;
-		    CvOUTSIDE_SEQ(innercv) = seq;
-		    SvREFCNT_inc(outercv);
+		    /* don't relink to grandfather if he's being freed */
+		    if (outercv && SvREFCNT(outercv)) {
+			CvWEAKOUTSIDE_off(innercv);
+			CvOUTSIDE(innercv) = outercv;
+			CvOUTSIDE_SEQ(innercv) = seq;
+			SvREFCNT_inc(outercv);
+		    }
+		    else {
+			CvOUTSIDE(innercv) = Nullcv;
+		    }
+
 		}
+
 	    }
 	}
     }
diff --git a/t/op/closure.t b/t/op/closure.t
index dd7b50cdef..763e2a74dc 100755
--- a/t/op/closure.t
+++ b/t/op/closure.t
@@ -13,7 +13,7 @@ BEGIN {
 
 use Config;
 
-print "1..184\n";
+print "1..185\n";
 
 my $test = 1;
 sub test (&) {
@@ -641,4 +641,27 @@ f16302();
     test { $a{7}->()->() + $a{11}->()->() == 18 };
 }
 
+# bugid #23265 - this used to coredump during destruction of PL_maincv
+# and its children
+
+require './test.pl';
+
+my $got = runperl(
+    prog => q[
+	print
+	    sub {$_[0]->(@_)} -> (
+		sub {
+		    $_[1]
+			?  $_[0]->($_[0], $_[1] - 1) .  sub {"x"}->()
+			: "y"
+		},   
+		2
+	    )
+	    , "\n"
+	;            
+    
+    ],
+    stderr => 1
+);
+test { $got eq "yxx\n" };