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, 2 insertions, 3 deletions

diff --git a/sv.c b/sv.c
index cea54d71c5..e3e5af4dc6 100644
--- a/sv.c
+++ b/sv.c
@@ -5757,10 +5757,9 @@ S_sv_unmagicext_flags(pTHX_ SV *const sv, const int type, MGVTBL *vtbl, const U3
 	if (SvMAGICAL(sv))	/* if we're under save_magic, wait for restore_magic; */
 	    mg_magical(sv);	/*    else fix the flags now */
     }
-    else {
+    else
 	SvMAGICAL_off(sv);
-	SvFLAGS(sv) |= (SvFLAGS(sv) & (SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
-    }
+
     return 0;
 }