From: Vincent Pit <vince@profvince.com>
Date: Tue, 20 Jan 2009 22:01:34 +0000 (+0100)
Subject: Don't call the free callback in global destruction
X-Git-Tag: v0.28~16
X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2FVariable-Magic.git;a=commitdiff_plain;h=b85f6ded9d3d67458fd9e3f37e0367d446e85d6a

Don't call the free callback in global destruction

Because in this case the wizard may not even exist anymore.

And test for that in t/15-self.t if either PERL_DESTRUCT_LEVEL is set or if
Perl::Destruct::Level is present.
---

diff --git a/Magic.xs b/Magic.xs
index 820d249..40997ed 100644
--- a/Magic.xs
+++ b/Magic.xs
@@ -568,17 +568,25 @@ STATIC int vmg_svt_clear(pTHX_ SV *sv, MAGIC *mg) {
 }
 
 STATIC int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
+ SV *wiz = (SV *) mg->mg_ptr;
+
+ /* This may happen in global destruction */
+ if (SvTYPE(wiz) == SVTYPEMASK)
+  return 0;
+
  /* So that it can survive tmp cleanup in vmg_cb_call */
  SvREFCNT_inc(sv);
+
 #if !VMG_HAS_PERL_MAINT(5, 11, 0, 32686)
  /* The previous magic tokens were freed but the magic chain wasn't updated, so
   * if you access the sv from the callback the old deleted magics will trigger
   * and cause memory misreads. Change 32686 solved it that way : */
  SvMAGIC_set(sv, mg);
 #endif
+
  /* Perl_mg_free will get rid of the magic and decrement mg->mg_obj and
   * mg->mg_ptr reference count */
- return vmg_cb_call1e(SV2MGWIZ(mg->mg_ptr)->cb_free, sv, mg->mg_obj);
+ return vmg_cb_call1e(SV2MGWIZ(wiz)->cb_free, sv, mg->mg_obj);
 }
 
 #if MGf_COPY
@@ -670,7 +678,7 @@ STATIC int vmg_wizard_free(pTHX_ SV *wiz, MAGIC *mg) {
  char buf[8];
  MGWIZ *w;
 
- if (PL_dirty) /* during global destruction, the context is already freed */
+ if (PL_dirty) /* During global destruction, the context is already freed */
   return 0;
 
  w = SV2MGWIZ(wiz);
diff --git a/t/15-self.t b/t/15-self.t
index cee1dbd..700cb17 100644
--- a/t/15-self.t
+++ b/t/15-self.t
@@ -50,4 +50,9 @@ my $c = 0;
  ok($res,   're-re-cast on self is valid');
 }
 
+if ((defined $ENV{PERL_DESTRUCT_LEVEL} and $ENV{PERL_DESTRUCT_LEVEL} >= 3)
+    or eval "use Perl::Destruct::Level level => 3; 1") {
+ diag 'Test global destruction';
+}
+
 # is($c, 0, 'magic destructor is called');