fixup correct handling of slurpy hash on odd number of elements

Author: leonerd

pp.c

@@ -7984,11 +7984,14 @@ PP(pp_multiparam)
         while(argc) {
             SV **svp;
 
-            svp = av_fetch(defav, parami, FALSE); parami++;
+            svp = av_fetch(defav, parami, FALSE); parami++; argc--;
             SV *name = svp ? *svp : &PL_sv_undef;
-            svp = av_fetch(defav, parami, FALSE); parami++;
-            SV *val = svp ? *svp : &PL_sv_undef;
-            argc -= 2;
+
+            SV *val = NULL;
+            if(argc) {
+                svp = av_fetch(defav, parami, FALSE); parami++; argc--;
+                val = svp ? *svp : &PL_sv_undef;
+            }
 
             STRLEN namelen;
             const char *namepv = SvPV(name, namelen);
@@ -8017,6 +8020,9 @@ PP(pp_multiparam)
                 if (UNLIKELY(TAINT_get) && !SvTAINTED(val))
                     TAINT_NOT;
 
+                if(!val)
+                    val = &PL_sv_undef;
+
                 SvPADSTALE_off(*padentry);
                 SvSetMagicSV(*padentry, val);
             }
@@ -8026,18 +8032,21 @@ PP(pp_multiparam)
                 assert(TAINTING_get || !TAINT_get);
                 if (UNLIKELY(TAINT_get) && !SvTAINTED(name))
                     TAINT_NOT;
-                if (UNLIKELY(TAINT_get) && !SvTAINTED(val))
-                    TAINT_NOT;
-
                 av_push(av, newSVsv(name));
-                av_push(av, newSVsv(val));
+
+                if(val) {
+                    if (UNLIKELY(TAINT_get) && !SvTAINTED(val))
+                        TAINT_NOT;
+                    av_push(av, newSVsv(val));
+                }
             }
             else if(slurpypad && slurpy == '%') {
                 HV *hv = (HV *)*slurpypad;
 
                 if (UNLIKELY(SvGMAGICAL(name)))
                     name = sv_mortalcopy(name);
 
+                assert(val); /* this must have passed the argc parity check */
                 if (UNLIKELY(TAINT_get) && !SvTAINTED(val))
                     TAINT_NOT;
                 hv_store_ent(hv, name, newSVsv(val), 0);

t/op/signatures.t

@@ -948,10 +948,13 @@ is eval("tnamed03(12, 34, x => 'X', y => 'Y')"), "a=12 b=34 x=X y=Y";
 sub tnamed04 (:$x, :$y, @rest) { "x=$x y=$y <@rest>"; }
 is prototype(\&tnamed04), undef;
 is eval("tnamed04(w => 'W', x => 'X', y => 'Y', z => 'Z')"), "x=X y=Y <w W z Z>";
+is eval("tnamed04(w => 'W', x => 'X', y => 'Y', 'single')"), "x=X y=Y <w W single>";
 
 sub tnamed05 (:$x, :$y, %rest) { "x=$x y=$y " . join(",", map { "$_=$rest{$_}" } sort keys %rest); }
 is prototype(\&tnamed05), undef;
 is eval("tnamed05(w => 'W', x => 'X', y => 'Y', z => 'Z')"), "x=X y=Y w=W,z=Z";
+is eval("tnamed05(w => 'W', x => 'X', y => 'Y', 'single')"), undef;
+like $@, qr{^Odd name/value argument for subroutine 'main::tnamed05' at };
 
 sub t085
     (