remove vestigial uses of PRIVSHIFT

This is a hangover from when a magic (e.g. tied) var, after calling
mg_get(), would only set the private (SVp_IOK,SVp_NOK,SVp_POK)
flags on the result, indicating that although it now had a valid integer
value (say), it wasn't a "real" integer. This was achieved by, after
calling mg_get(), shifting all the public flags by PRIVSHIFT to convert
them to private flags.

Since 5.18.0, that's not been the case (i.e. mg_get() on a tied var leaves
Svf_IOK etc set). But there are still a couple of vestigial uses of
PRIVSHIFT in the core, and this commit removes them.

For one of them, I added a test that shows that (in slightly contrived
circumnstances), it was possible for a SVp_IOK NV to be upgraded
to a SVf_IOK int on return from localisation, losing its fractional
component.

The other one, in S_sv_unmagicext_flags(), only seemed to get called
when setting a new value (e.g. from mg_set()), so its unlikely that such a
var would still have private flags set that could be incorrectly upgraded
to public.

1 files changed, 6 insertions, 9 deletions

diff --git a/scope.c b/scope.c
index c08eda06c8..375240eee4 100644
--- a/scope.c
+++ b/scope.c
@@ -210,15 +210,12 @@ S_save_scalar_at(pTHX_ SV **sptr, const U32 flags)
     PERL_ARGS_ASSERT_SAVE_SCALAR_AT;
 
     osv = *sptr;
-    sv  = (flags & SAVEf_KEEPOLDELEM) ? osv : (*sptr = newSV(0));
-
-    if (SvTYPE(osv) >= SVt_PVMG && SvMAGIC(osv)) {
-	if (SvGMAGICAL(osv)) {
-	    SvFLAGS(osv) |= (SvFLAGS(osv) &
-	       (SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
-	}
-	if (!(flags & SAVEf_KEEPOLDELEM))
-	    mg_localize(osv, sv, cBOOL(flags & SAVEf_SETMAGIC));
+    if (flags & SAVEf_KEEPOLDELEM)
+        sv = osv;
+    else {
+        sv  = (*sptr = newSV(0));
+        if (SvTYPE(osv) >= SVt_PVMG && SvMAGIC(osv))
+            mg_localize(osv, sv, cBOOL(flags & SAVEf_SETMAGIC));
     }
 
     return sv;