From: Vincent Pit <vince@profvince.com>
Date: Thu, 15 Apr 2010 23:00:27 +0000 (+0200)
Subject: Properly vivify nonexistent glob slots
X-Git-Tag: rt55593^0
X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2FScope-Upper.git;a=commitdiff_plain;h=44bbbdcdafa5707a753abb9de5c5d01cd7388880

Properly vivify nonexistent glob slots

This fixes RT #55593.
---

diff --git a/Upper.xs b/Upper.xs
index bb1150c..20fa5d6 100644
--- a/Upper.xs
+++ b/Upper.xs
@@ -421,11 +421,11 @@ STATIC void su_localize(pTHX_ void *ud_) {
   gv = (GV *) sv;
  } else {
 #ifdef gv_fetchsv
-  gv = gv_fetchsv(sv, GV_ADDMULTI, SVt_PVGV);
+  gv = gv_fetchsv(sv, GV_ADDMULTI, t);
 #else
   STRLEN len;
   const char *name = SvPV_const(sv, len);
-  gv = gv_fetchpvn_flags(name, len, GV_ADDMULTI, SVt_PVGV);
+  gv = gv_fetchpvn_flags(name, len, GV_ADDMULTI, t);
 #endif
  }
 
diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm
index 91219ff..84de02e 100644
--- a/lib/Scope/Upper.pm
+++ b/lib/Scope/Upper.pm
@@ -162,6 +162,10 @@ For example,
 
 will localize C<$Tool::tag> and not C<$Scope::tag>.
 
+Note that if C<$what> is a string denoting a variable that wasn't declared beforehand, the relevant slot will be vivified as needed and won't be deleted from the glob when the localization ends.
+This situation never arises with C<local> because it only compiles when the localized variable is already declared.
+Although I believe it shouldn't be a problem as glob slots definedness is pretty much an implementation detail, this behaviour may change in the future if proved harmful.
+
 =back
 
 =head2 C<localize_elem $what, $key, $value, $context>
@@ -170,6 +174,8 @@ Similar to L</localize> but for array and hash elements.
 If C<$what> is a glob, the slot to fill is determined from which type of reference C<$value> is ; otherwise it's inferred from the sigil.
 C<$key> is either an array index or a hash key, depending of which kind of variable you localize.
 
+Just like for L</localize>, when C<$what> is a string pointing to an undeclared variable, it will be vivified but the variable itself will be empty when the localization ends (although it will still exist in its parent glob).
+
 =head2 C<localize_delete $what, $key, $context>
 
 Similiar to L</localize>, but for deleting variables or array/hash elements.
diff --git a/t/30-localize_elem-target.t b/t/30-localize_elem-target.t
index 79ce8ee..273eb0d 100644
--- a/t/30-localize_elem-target.t
+++ b/t/30-localize_elem-target.t
@@ -3,7 +3,7 @@
 use strict;
 use warnings;
 
-use Test::More tests => 21;
+use Test::More tests => 25;
 
 use Scope::Upper qw/localize_elem UP HERE/;
 
@@ -73,6 +73,16 @@ our @a;
  is_deeply \@a, [ 4 .. 6 ], 'localize_elem "@a", 4, 12 => UP [end]';
 }
 
+{
+ {
+  localize_elem '@nonexistent', 2, 7;
+  is_deeply eval('*nonexistent{ARRAY}'), [ undef, undef, 7 ],
+                             'localize_elem "@nonexistent", 2, 7 => HERE [ok]';
+ }
+ is_deeply eval('*nonexistent{ARRAY}'), [ ],
+                             'localize_elem "@nonexistent", 2, 7 => HERE [end]';
+}
+
 # Hashes
 
 our %h;
@@ -108,3 +118,12 @@ our %h;
  is_deeply \%h, { a => 1, b => 2 }, 'localize_elem "%h", "a", 5 => UP [end]';
 }
 
+{
+ {
+  localize_elem '%nonexistent', 'a', 13;
+  is_deeply eval('*nonexistent{HASH}'), { a => 13 },
+                          'localize_elem "%nonexistent", "a", 13 => HERE [ok]';
+ }
+ is_deeply eval('*nonexistent{HASH}'), { },
+                          'localize_elem "%nonexistent", "a", 13 => HERE [end]';
+}
diff --git a/t/40-localize_delete-target.t b/t/40-localize_delete-target.t
index 999fe9e..b51c28b 100644
--- a/t/40-localize_delete-target.t
+++ b/t/40-localize_delete-target.t
@@ -3,7 +3,7 @@
 use strict;
 use warnings;
 
-use Test::More tests => 36;
+use Test::More tests => 44;
 
 use Scope::Upper qw/localize_delete UP HERE/;
 
@@ -107,6 +107,16 @@ our @a;
  is_deeply \@a, [ 4 .. 6 ], 'localize_delete "@a", 4 (exists) => UP [end]';
 }
 
+{
+ {
+  localize_delete '@nonexistent', 2;
+  is_deeply eval('*nonexistent{ARRAY}'), [ ],
+                       'localize_delete "@nonexistent", anything => HERE [ok]';
+ }
+ is_deeply eval('*nonexistent{ARRAY}'), [ ],
+                       'localize_delete "@nonexistent", anything => HERE [end]';
+}
+
 # Hashes
 
 our %h;
@@ -142,6 +152,16 @@ our %h;
  is_deeply \%h, { a => 1, b => 2 }, 'localize_delete "%h", "a" => UP [end]';
 }
 
+{
+ {
+  localize_delete '%nonexistent', 'a';
+  is_deeply eval('*nonexistent{HASH}'), { },
+                       'localize_delete "%nonexistent", anything => HERE [ok]';
+ }
+ is_deeply eval('*nonexistent{HASH}'), { },
+                       'localize_delete "%nonexistent", anything => HERE [end]';
+}
+
 # Others
 
 our $x = 1;
@@ -151,6 +171,16 @@ our $x = 1;
 }
 is $x, 1, 'localize_delete "$x", anything => HERE [end]';
 
+{
+ {
+  localize_delete '$nonexistent', 2;
+  is eval('${*nonexistent{SCALAR}}'), undef,
+                       'localize_delete "$nonexistent", anything => HERE [ok]';
+ }
+ is eval('${*nonexistent{SCALAR}}'), undef,
+                       'localize_delete "$nonexistent", anything => HERE [end]';
+}
+
 sub x { 1 };
 {
  localize_delete '&x', 2 => HERE;
@@ -158,6 +188,16 @@ sub x { 1 };
 }
 is x(), 1, 'localize_delete "&x", anything => HERE [end]';
 
+{
+ {
+  localize_delete '&nonexistent', 2;
+  is eval('exists &nonexistent'), !1,
+                       'localize_delete "&nonexistent", anything => HERE [ok]';
+ }
+ is eval('exists &nonexistent'), !1,
+                       'localize_delete "&nonexistent", anything => HERE [end]';
+}
+
 {
  localize_delete *x, sub { } => HERE;
  is !exists(&x),  1, 'localize_delete *x, anything => HERE [ok 1]';