Fix skip logic in pad_tidy and cv_clone

Commit 325e1816dc changed the logic for determining whether a pad
entry is to be treated like a constant; i.e., shared between recursion
levels and sub clones.

According the old logic, a pad entry must be shared if it is marked
READONLY or is a shared hash key scalar.  According to the new logic,
the entry must be shared if the pad name has a zero-length PV (i.e.,
&PL_sv_no).

Two pieces of code were still following the old logic.  Changing them
fixes this old bug:

my $close_over_me;
sub  {
    () = $close_over_me;
    open my $fh, "/dev/null";
    print "$$fh\n"
}->();
__END__

Output:
*main::

The name attached to the implicit rv2gv op in open() was not being
copied by sub clones.

The previous commit is also part of the fix.

In the tests, I tested the combination of sub cloning and recursion,
since it seemed like a good idea (and also as a result of copying and
pasting :-).

S_pmtrans was still relying on the old logic, so it gets changed, too.

3 files changed, 22 insertions, 8 deletions

diff --git a/op.c b/op.c
index 44d2f203fb..c5964eb88f 100644
--- a/op.c
+++ b/op.c
@@ -4268,7 +4268,7 @@ S_pmtrans(pTHX_ OP *o, OP *expr, OP *repl)
 
 	swash = MUTABLE_SV(swash_init("utf8", "", listsv, bits, none));
 #ifdef USE_ITHREADS
-	cPADOPo->op_padix = pad_alloc(OP_TRANS, SVs_PADTMP);
+	cPADOPo->op_padix = pad_alloc(OP_TRANS, SVf_READONLY);
 	SvREFCNT_dec(PAD_SVl(cPADOPo->op_padix));
 	PAD_SETSV(cPADOPo->op_padix, swash);
 	SvPADTMP_on(swash);
diff --git a/pad.c b/pad.c
index d2b6c4fd81..d8d9322c60 100644
--- a/pad.c
+++ b/pad.c
@@ -1773,16 +1773,16 @@ Perl_pad_tidy(pTHX_ padtidy_type type)
 	for (ix = AvFILLp(PL_comppad); ix > 0; ix--) {
 	    SV *namesv;
 
-	    if (SvIMMORTAL(PL_curpad[ix]) || IS_PADGV(PL_curpad[ix]) || IS_PADCONST(PL_curpad[ix]))
-		continue;
 	    /*
 	     * The only things that a clonable function needs in its
-	     * pad are anonymous subs.
+	     * pad are anonymous subs, constants and GVs.
 	     * The rest are created anew during cloning.
 	     */
+	    if (SvIMMORTAL(PL_curpad[ix]) || IS_PADGV(PL_curpad[ix]))
+		continue;
 	    if (!((namesv = namep[ix]) != NULL &&
-		  namesv != &PL_sv_undef &&
-		   *SvPVX_const(namesv) == '&'))
+		  PadnamePV(namesv) &&
+		   (!PadnameLEN(namesv) || *SvPVX_const(namesv) == '&')))
 	    {
 		SvREFCNT_dec(PL_curpad[ix]);
 		PL_curpad[ix] = NULL;
@@ -2120,7 +2120,7 @@ S_cv_clone_pad(pTHX_ CV *proto, CV *cv, CV *outside, bool newcv)
 		    SvPADSTALE_on(sv);
 	    }
 	}
-	else if (IS_PADGV(ppad[ix]) || IS_PADCONST(ppad[ix])) {
+	else if (IS_PADGV(ppad[ix]) || (namesv && PadnamePV(namesv))) {
 	    sv = SvREFCNT_inc_NN(ppad[ix]);
 	}
 	else {
diff --git a/t/op/gv.t b/t/op/gv.t
index c01c5d21c2..7494e09ab8 100644
--- a/t/op/gv.t
+++ b/t/op/gv.t
@@ -12,7 +12,7 @@ BEGIN {
 
 use warnings;
 
-plan( tests => 253 );
+plan( tests => 254 );
 
 # type coercion on assignment
 $foo = 'foo';
@@ -651,6 +651,20 @@ is join(' ', r(4)),
   '*main::$fh *main::$fh *main::$fh *main::$fh *main::$fh',
   'recursion does not cause lex handles to lose their names';
 
+# And sub cloning, too; not just recursion
+my $close_over_me;
+is join(' ', sub {
+    () = $close_over_me;
+    my @output;
+    @output = CORE::__SUB__->($_[0]-1) if $_[0];
+    open my $fh, "TEST";
+    push @output, $$fh;
+    close $fh;
+    @output;
+   }->(4)),
+  '*main::$fh *main::$fh *main::$fh *main::$fh *main::$fh',
+  'sub cloning does not cause lex handles to lose their names';
+
 # [perl #71254] - Assigning a glob to a variable that has a current
 # match position. (We are testing that Perl_magic_setmglob respects globs'
 # special used of SvSCREAM.)