From: Chip Salzenberg <chip@pobox.com>
Date: Mon, 10 Nov 2008 16:00:40 +0000 (-0800)
Subject: Re: [perl #60360] [PATCH] local $SIG{FOO} = sub {...}; sets signal
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=9711599ee3b2375539002b6ddc0873ec478916bb;p=p5sagit%2Fp5-mst-13.2.git

Re: [perl #60360] [PATCH] local $SIG{FOO} = sub {...}; sets signal
Message-ID: <20081111000040.GB19329@tytlal.topaz.cx>

p4raw-id: //depot/perl@34819
---

diff --git a/embed.fnc b/embed.fnc
index c3835b3..67fd70f 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -518,7 +518,7 @@ Apd	|void	|sortsv_flags	|NULLOK SV** array|size_t num_elts|NN SVCOMPARE_t cmp|U3
 Apd	|int	|mg_clear	|NN SV* sv
 Apd	|int	|mg_copy	|NN SV *sv|NN SV *nsv|NULLOK const char *key \
 				|I32 klen
-pd	|void	|mg_localize	|NN SV* sv|NN SV* nsv
+pd	|void	|mg_localize	|NN SV* sv|NN SV* nsv|I32 empty
 ApdR	|MAGIC*	|mg_find	|NULLOK const SV* sv|int type
 Apd	|int	|mg_free	|NN SV* sv
 Apd	|int	|mg_get		|NN SV* sv
@@ -790,7 +790,7 @@ Ap	|void	|save_generic_pvref|NN char** str
 Ap	|void	|save_shared_pvref|NN char** str
 Ap	|void	|save_gp	|NN GV* gv|I32 empty
 Ap	|HV*	|save_hash	|NN GV* gv
-Ap	|void	|save_helem	|NN HV *hv|NN SV *key|NN SV **sptr
+Ap	|void	|save_helem	|NN HV *hv|NN SV *key|NN SV **sptr|I32 empty
 Ap	|void	|save_hptr	|NN HV** hptr
 Ap	|void	|save_I16	|NN I16* intp
 Ap	|void	|save_I32	|NN I32* intp
@@ -1550,7 +1550,7 @@ s	|SV*	|pm_description	|NN const PMOP *pm
 #endif
 
 #if defined(PERL_IN_SCOPE_C) || defined(PERL_DECL_PROT)
-s	|SV*	|save_scalar_at	|NN SV **sptr
+s	|SV*	|save_scalar_at	|NN SV **sptr|I32 empty
 #endif
 
 #if defined(PERL_IN_GV_C) || defined(PERL_IN_SV_C) || defined(PERL_IN_PAD_C) || defined(PERL_DECL_PROT)
diff --git a/embed.h b/embed.h
index ace2037..b7b3dbd 100644
--- a/embed.h
+++ b/embed.h
@@ -2795,7 +2795,7 @@
 #define mg_clear(a)		Perl_mg_clear(aTHX_ a)
 #define mg_copy(a,b,c,d)	Perl_mg_copy(aTHX_ a,b,c,d)
 #ifdef PERL_CORE
-#define mg_localize(a,b)	Perl_mg_localize(aTHX_ a,b)
+#define mg_localize(a,b,c)	Perl_mg_localize(aTHX_ a,b,c)
 #endif
 #define mg_find(a,b)		Perl_mg_find(aTHX_ a,b)
 #define mg_free(a)		Perl_mg_free(aTHX_ a)
@@ -3086,7 +3086,7 @@
 #define save_shared_pvref(a)	Perl_save_shared_pvref(aTHX_ a)
 #define save_gp(a,b)		Perl_save_gp(aTHX_ a,b)
 #define save_hash(a)		Perl_save_hash(aTHX_ a)
-#define save_helem(a,b,c)	Perl_save_helem(aTHX_ a,b,c)
+#define save_helem(a,b,c,d)	Perl_save_helem(aTHX_ a,b,c,d)
 #define save_hptr(a)		Perl_save_hptr(aTHX_ a)
 #define save_I16(a)		Perl_save_I16(aTHX_ a)
 #define save_I32(a)		Perl_save_I32(aTHX_ a)
@@ -3790,7 +3790,7 @@
 #endif
 #if defined(PERL_IN_SCOPE_C) || defined(PERL_DECL_PROT)
 #ifdef PERL_CORE
-#define save_scalar_at(a)	S_save_scalar_at(aTHX_ a)
+#define save_scalar_at(a,b)	S_save_scalar_at(aTHX_ a,b)
 #endif
 #endif
 #if defined(PERL_IN_GV_C) || defined(PERL_IN_SV_C) || defined(PERL_IN_PAD_C) || defined(PERL_DECL_PROT)
diff --git a/mg.c b/mg.c
index 28eb9d2..22f8c99 100644
--- a/mg.c
+++ b/mg.c
@@ -463,15 +463,19 @@ Perl_mg_copy(pTHX_ SV *sv, SV *nsv, const char *key, I32 klen)
 /*
 =for apidoc mg_localize
 
-Copy some of the magic from an existing SV to new localized version of
-that SV. Container magic (eg %ENV, $1, tie) gets copied, value magic
-doesn't (eg taint, pos).
+Copy some of the magic from an existing SV to new localized version of that
+SV. Container magic (eg %ENV, $1, tie) gets copied, value magic doesn't (eg
+taint, pos).
+
+If empty is false then no set magic will be called on the new (empty) SV.
+This typically means that assignment will soon follow (e.g. 'local $x = $y'),
+and that will handle the magic.
 
 =cut
 */
 
 void
-Perl_mg_localize(pTHX_ SV *sv, SV *nsv)
+Perl_mg_localize(pTHX_ SV *sv, SV *nsv, I32 empty)
 {
     dVAR;
     MAGIC *mg;
@@ -495,9 +499,11 @@ Perl_mg_localize(pTHX_ SV *sv, SV *nsv)
 
     if (SvTYPE(nsv) >= SVt_PVMG && SvMAGIC(nsv)) {
 	SvFLAGS(nsv) |= SvMAGICAL(sv);
-	PL_localizing = 1;
-	SvSETMAGIC(nsv);
-	PL_localizing = 0;
+	if (empty) {
+	    PL_localizing = 1;
+	    SvSETMAGIC(nsv);
+	    PL_localizing = 0;
+	}
     }	    
 }
 
diff --git a/op.h b/op.h
index c1120f7..6729f6e 100644
--- a/op.h
+++ b/op.h
@@ -137,6 +137,9 @@ Deprecated.  Use C<GIMME_V> instead.
 				/*  On OP_SMARTMATCH, an implicit smartmatch */
 				/*  On OP_ANONHASH and OP_ANONLIST, create a
 				    reference to the new anon hash or array */
+				/*  On OP_HELEM and OP_HSLICE, localization will be followed
+				    by assignment, so do not wipe the target if it is special
+				    (e.g. a glob or a magic SV) */
 
 /* old names; don't use in new code, but don't break them, either */
 #define OPf_LIST	OPf_WANT_LIST
diff --git a/pp.c b/pp.c
index 7fe6c8a..304e42d 100644
--- a/pp.c
+++ b/pp.c
@@ -4185,7 +4185,7 @@ PP(pp_hslice)
 		    save_gp(MUTABLE_GV(*svp), !(PL_op->op_flags & OPf_SPECIAL));
 		else {
 		    if (preeminent)
-			save_helem(hv, keysv, svp);
+			save_helem(hv, keysv, svp, !(PL_op->op_flags & OPf_SPECIAL));
 		    else {
 			STRLEN keylen;
 			const char * const key = SvPV_const(keysv, keylen);
diff --git a/pp_hot.c b/pp_hot.c
index 6450e25..4624fbb 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -1828,7 +1828,7 @@ PP(pp_helem)
 		    SAVEDELETE(hv, savepvn(key,keylen),
 			       SvUTF8(keysv) ? -(I32)keylen : (I32)keylen);
 		} else
-		    save_helem(hv, keysv, svp);
+		    save_helem(hv, keysv, svp, !(PL_op->op_flags & OPf_SPECIAL));
             }
 	}
 	else if (PL_op->op_private & OPpDEREF)
diff --git a/proto.h b/proto.h
index c466fba..f1f8dce 100644
--- a/proto.h
+++ b/proto.h
@@ -1848,7 +1848,7 @@ PERL_CALLCONV int	Perl_mg_copy(pTHX_ SV *sv, SV *nsv, const char *key, I32 klen)
 #define PERL_ARGS_ASSERT_MG_COPY	\
 	assert(sv); assert(nsv)
 
-PERL_CALLCONV void	Perl_mg_localize(pTHX_ SV* sv, SV* nsv)
+PERL_CALLCONV void	Perl_mg_localize(pTHX_ SV* sv, SV* nsv, I32 empty)
 			__attribute__nonnull__(pTHX_1)
 			__attribute__nonnull__(pTHX_2);
 #define PERL_ARGS_ASSERT_MG_LOCALIZE	\
@@ -2830,7 +2830,7 @@ PERL_CALLCONV HV*	Perl_save_hash(pTHX_ GV* gv)
 #define PERL_ARGS_ASSERT_SAVE_HASH	\
 	assert(gv)
 
-PERL_CALLCONV void	Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr)
+PERL_CALLCONV void	Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr, I32 empty)
 			__attribute__nonnull__(pTHX_1)
 			__attribute__nonnull__(pTHX_2)
 			__attribute__nonnull__(pTHX_3);
@@ -5498,7 +5498,7 @@ STATIC SV*	S_pm_description(pTHX_ const PMOP *pm)
 #endif
 
 #if defined(PERL_IN_SCOPE_C) || defined(PERL_DECL_PROT)
-STATIC SV*	S_save_scalar_at(pTHX_ SV **sptr)
+STATIC SV*	S_save_scalar_at(pTHX_ SV **sptr, I32 empty)
 			__attribute__nonnull__(pTHX_1);
 #define PERL_ARGS_ASSERT_SAVE_SCALAR_AT	\
 	assert(sptr)
diff --git a/scope.c b/scope.c
index d9dcd4a..83e8a7b 100644
--- a/scope.c
+++ b/scope.c
@@ -164,7 +164,7 @@ Perl_free_tmps(pTHX)
 }
 
 STATIC SV *
-S_save_scalar_at(pTHX_ SV **sptr)
+S_save_scalar_at(pTHX_ SV **sptr, I32 empty)
 {
     dVAR;
     SV * const osv = *sptr;
@@ -179,7 +179,7 @@ S_save_scalar_at(pTHX_ SV **sptr)
 	       (SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
 	    PL_tainted = oldtainted;
 	}
-	mg_localize(osv, sv);
+	mg_localize(osv, sv, empty);
     }
     return sv;
 }
@@ -199,7 +199,7 @@ Perl_save_scalar(pTHX_ GV *gv)
     SSPUSHPTR(SvREFCNT_inc_simple(gv));
     SSPUSHPTR(SvREFCNT_inc(*sptr));
     SSPUSHINT(SAVEt_SV);
-    return save_scalar_at(sptr);
+    return save_scalar_at(sptr, TRUE);	/* XXX - FIXME - see #60360 */
 }
 
 /* Like save_sptr(), but also SvREFCNT_dec()s the new value.  Can be used to
@@ -321,7 +321,7 @@ Perl_save_ary(pTHX_ GV *gv)
     GvAV(gv) = NULL;
     av = GvAVn(gv);
     if (SvMAGIC(oav))
-	mg_localize(MUTABLE_SV(oav), MUTABLE_SV(av));
+	mg_localize(MUTABLE_SV(oav), MUTABLE_SV(av), TRUE);
     return av;
 }
 
@@ -341,7 +341,7 @@ Perl_save_hash(pTHX_ GV *gv)
     GvHV(gv) = NULL;
     hv = GvHVn(gv);
     if (SvMAGIC(ohv))
-	mg_localize(MUTABLE_SV(ohv), MUTABLE_SV(hv));
+	mg_localize(MUTABLE_SV(ohv), MUTABLE_SV(hv), TRUE);
     return hv;
 }
 
@@ -611,7 +611,7 @@ Perl_save_aelem(pTHX_ AV *av, I32 idx, SV **sptr)
     /* if it gets reified later, the restore will have the wrong refcnt */
     if (!AvREAL(av) && AvREIFY(av))
 	SvREFCNT_inc_void(*sptr);
-    save_scalar_at(sptr);
+    save_scalar_at(sptr, TRUE);	/* XXX - FIXME - see #60360 */
     sv = *sptr;
     /* If we're localizing a tied array element, this new sv
      * won't actually be stored in the array - so it won't get
@@ -622,7 +622,7 @@ Perl_save_aelem(pTHX_ AV *av, I32 idx, SV **sptr)
 }
 
 void
-Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr)
+Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr, I32 empty)
 {
     dVAR;
     SV *sv;
@@ -635,7 +635,7 @@ Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr)
     SSPUSHPTR(newSVsv(key));
     SSPUSHPTR(SvREFCNT_inc(*sptr));
     SSPUSHINT(SAVEt_HELEM);
-    save_scalar_at(sptr);
+    save_scalar_at(sptr, empty);
     sv = *sptr;
     /* If we're localizing a tied hash element, this new sv
      * won't actually be stored in the hash - so it won't get
@@ -657,7 +657,7 @@ Perl_save_svref(pTHX_ SV **sptr)
     SSPUSHPTR(sptr);
     SSPUSHPTR(SvREFCNT_inc(*sptr));
     SSPUSHINT(SAVEt_SVREF);
-    return save_scalar_at(sptr);
+    return save_scalar_at(sptr, TRUE);	/* XXX - FIXME - see #60360 */
 }
 
 void