From: Vincent Pit <perl@profvince.com>
Date: Wed, 7 Dec 2016 00:55:57 +0000 (-0200)
Subject: Only enable careful self destruction on perl 5.25.3 and higher
X-Git-Tag: v0.61~3
X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2FVariable-Magic.git;a=commitdiff_plain;h=7ffa818799831666a3a166baa292421f7c03809b

Only enable careful self destruction on perl 5.25.3 and higher
---

diff --git a/Magic.xs b/Magic.xs
index ba59f54..001f608 100644
--- a/Magic.xs
+++ b/Magic.xs
@@ -187,6 +187,8 @@ static OP *vmg_trampoline_bump(pTHX_ vmg_trampoline *t, SV *sv, OP *o) {
 # define OP_CLASS(O) (PL_opargs[(O)->op_type] & OA_CLASS_MASK)
 #endif
 
+#define VMG_CAREFUL_SELF_DESTRUCTION XSH_HAS_PERL(5, 25, 3)
+
 /* ... Bug-free mg_magical ................................................. */
 
 /* See the discussion at http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2008-01/msg00036.html */
@@ -1420,7 +1422,9 @@ static MGVTBL vmg_propagate_errsv_vtbl = {
 
 typedef struct {
  SV  *sv;
+#if VMG_CAREFUL_SELF_DESTRUCTION
  SV  *rsv; /* The ref to the sv currently being freed, pushed on the stack */
+#endif
  int  in_eval;
  I32  base;
 } vmg_svt_free_cleanup_ud;
@@ -1465,6 +1469,7 @@ static int vmg_svt_free_cleanup(pTHX_ void *ud_) {
   SV    *sv = ud->sv;
   MAGIC *mg;
 
+#if VMG_CAREFUL_SELF_DESTRUCTION
  /* Silently undo the ref - don't trigger destruction in the referent
   * for a second time */
  if (SvROK(ud->rsv) && SvRV(ud->rsv) == sv) {
@@ -1473,6 +1478,7 @@ static int vmg_svt_free_cleanup(pTHX_ void *ud_) {
   SvROK_off(ud->rsv);
  }
  SvREFCNT_dec_NN(ud->rsv);
+#endif
 
   /* We are about to croak() while sv is being destroyed. Try to clean up
    * things a bit. */
@@ -1532,8 +1538,12 @@ static int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
  PUSHMARK(SP);
  EXTEND(SP, 2);
  /* This will bump the refcount of sv from 0 to 1 */
+#if VMG_CAREFUL_SELF_DESTRUCTION
  ud.rsv = newRV_inc(sv);
  PUSHs(ud.rsv);
+#else
+ PUSHs(sv_2mortal(newRV_inc(sv)));
+#endif
  PUSHs(mg->mg_obj ? mg->mg_obj : &PL_sv_undef);
  if (w->opinfo)
   XPUSHs(vmg_op_info(w->opinfo));
@@ -1560,6 +1570,7 @@ static int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
 
  POPSTACK;
 
+#if VMG_CAREFUL_SELF_DESTRUCTION
  /* Silently undo the ref - don't trigger destruction in the referent
   * for a second time */
  if (SvROK(ud.rsv) && SvRV(ud.rsv) == sv) {
@@ -1568,6 +1579,7 @@ static int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
   --SvREFCNT(sv); /* silent */
  }
  SvREFCNT_dec_NN(ud.rsv);
+#endif
 
  FREETMPS;
  LEAVE;