add CVf_CVGV_RC flag

after the recent commit 803f274831f937654d48f8cf0468521cbf8f5dff,
the CvGV field is sometimes reference counted. Since it was intended that
the reference counting would happen only for anonymous CVs, the CVf_ANON
flag was co-opted to indicate whether RC was being used. This is not
entirely robust; for example, sub __ANON__ {} is a non-anon sub which
points to the same GV used by anon subs, which while itself doesn't
directly break things, shows that the potential for breakage is there.

So add a separate flag just to indicate the reference count status of the
CvGV field.

1 files changed, 2 insertions, 1 deletions

diff --git a/sv.c b/sv.c
index f555fc15ac..1e756f2420 100644
--- a/sv.c
+++ b/sv.c
@@ -5687,6 +5687,7 @@ S_anonymise_cv_maybe(pTHX_ GV *gv, CV* cv)
     SvREFCNT_dec(gvname);
 
     CvANON_on(cv);
+    CvCVGV_RC_on(cv);
     CvGV(cv) = MUTABLE_GV(SvREFCNT_inc(anongv));
 }
 
@@ -11438,7 +11439,7 @@ S_sv_dup_common(pTHX_ const SV *const sstr, CLONE_PARAMS *const param)
 		/* don't dup if copying back - CvGV isn't refcounted, so the
 		 * duped GV may never be freed. A bit of a hack! DAPM */
 		CvGV(dstr) =
-		    CvANON(dstr)
+		    CvCVGV_RC(dstr)
 		    ? gv_dup_inc(CvGV(sstr), param)
 		    : (param->flags & CLONEf_JOIN_IN)
 			? NULL