Data::Walk Bug Report and Patch

data-walk-email-bug-report.txt

Subject: Top Level Object should not have a container

Data::Walk Version 2.01 assigns `container` and `type` for top-level objects
in an inconsistent way. On one hand, A scalar at top level gets the
arrayref of `@args` as `container`, and `ARRAY` as `type`. Whereas
a hashref, or arrayref, at top-level gets *ITSELF* as the `container`,
and its own ref type (`ARRAY|HASH`) as `type`. The latter behaviour
is not consistent because it implies that the item is contained in
itself.
    
A set of rules for consistent behaviour regarding top-level objects can be:
- Top level object passed to `walk` has `$Data::Walk::depth == 1`.
- `$Data::Walk::container` and `$Data::Walk::type` is `undef` for such objects.
  (They have no container, and hence, no container type.)

A patch against commit b3f9af86587a513d9a3a1e8f318ef6a30e328872 is included
here.

Summary of Changes:
    
- new file:   t/05bug-container-type-at-depth-one.t
    
  Tests the above consistent behaviour for
  the following calls of `Data::Walk::walk`:
    - Single hashref argument
      `walk sub { ... }, $hashref;`
    - Single arrayref argument
      `walk sub { ... }, $arrayref;`
    - Many argument with the first one as scalar
      `walk sub { ... }, 5, $hash,$arrayref;`
    
- modified:   t/04bug-container-type-by-depth.t
    
  Makes the test compliant to the above mentioned consistent behaviour.

- modified: lib/Data/Walk.pm

  Fix setting of Top-Level Objects' container

fix-setting-top-level-container.patch
-------------------------------------
diff --git a/lib/Data/Walk.pm b/lib/Data/Walk.pm
index 1ca491c..b714ce6 100755
--- a/lib/Data/Walk.pm
+++ b/lib/Data/Walk.pm
@@ -71,23 +71,7 @@ sub __walk {
 
     local $index = 0;
     foreach my $item (@args) {
-        local ($container, $type, $depth);
-        if (ref $item) {
-            if (UNIVERSAL::isa ($item, 'HASH')) {
-                $container = $item;
-                $type = 'HASH';
-            } elsif (UNIVERSAL::isa ($item, 'ARRAY')) {
-                $container = $item;
-                $type = 'ARRAY';
-            } else {
-                $container = \@args;
-                $type = 'ARRAY';
-            }
-        } else {
-            $container = \@args;
-            $type = 'ARRAY';
-        }
-        $depth = 0;
+        local $depth = 0;
         __recurse $options, $item;
         ++$index;
     }
diff --git a/t/04bug-container-type-by-depth.t b/t/04bug-container-type-by-depth.t
index 6bed43c..3f18435 100755
--- a/t/04bug-container-type-by-depth.t
+++ b/t/04bug-container-type-by-depth.t
@@ -23,14 +23,36 @@ use Test;
 use Data::Walk;
 
 BEGIN {
-    plan tests => 10;
+    plan tests => 20;
 }
 
 my $data = {
     foo => 'bar',
     baz => 'bazoo',
 };
-walk sub {
-    ok $Data::Walk::type, 'HASH';
-    ok $Data::Walk::container, $data;
-}, $data;
+
+Data::Walk::walk +{
+       wanted      => sub {
+         if ($Data::Walk::depth == 1)  {
+           ok $Data::Walk::type, undef;
+           ok $Data::Walk::container, undef;
+         } elsif ($Data::Walk::depth == 2) {
+           ok $Data::Walk::type, 'HASH';
+           ok $Data::Walk::container, $data;
+         }
+       },
+       bydepth     => 1
+      }, $data;
+Data::Walk::walk +{
+       wanted      => sub {
+         if ($Data::Walk::depth == 1)  {
+           ok $Data::Walk::type, undef;
+           ok $Data::Walk::container, undef;
+         } elsif ($Data::Walk::depth == 2) {
+           ok $Data::Walk::type, 'HASH';
+           ok $Data::Walk::container, $data;
+         }
+       },
+       bydepth     => 0
+      }, $data;
+__END__
diff --git a/t/05bug-container-type-at-depth-one.t b/t/05bug-container-type-at-depth-one.t
new file mode 100644
index 0000000..027aff0
--- /dev/null
+++ b/t/05bug-container-type-at-depth-one.t
@@ -0,0 +1,83 @@
+# Data::Walk - Traverse Perl data structures.
+# Copyright (C) 2005-2016 Guido Flohr <guido.flohr@cantanea.com>,
+# all rights reserved.
+
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Library General Public License as published
+# by the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Library General Public License for more details.
+
+# You should have received a copy of the GNU Library General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+# USA.
+
+use strict;
+
+use Test;
+use Data::Walk;
+
+BEGIN {
+    plan tests => 28;
+}
+
+my $hash = {
+    foo => 'bar',
+    baz => 'bazoo',
+};
+
+my $arr = [
+  "moo",
+  "foo",
+  1
+];
+
+walk sub {
+  if ($Data::Walk::depth == 1) {
+    #The top level has no container
+    ok $Data::Walk::type, undef;
+    #Hence no type for container
+    ok $Data::Walk::container, undef;
+  }
+  elsif ( $Data::Walk::depth == 2) {
+    ok $Data::Walk::type, q/HASH/;
+    ok $Data::Walk::container, $hash;
+  }
+}, $hash;
+
+
+walk sub {
+  if ($Data::Walk::depth == 1) {
+    #The top level has no container
+    ok $Data::Walk::type, undef;
+    #Hence no type for container
+    ok $Data::Walk::container, undef;
+  }
+  elsif ( $Data::Walk::depth == 2) {
+    ok $Data::Walk::type, q/ARRAY/;
+    ok $Data::Walk::container, $arr;
+  }
+}, $arr;
+
+walk sub {
+  if ($Data::Walk::depth == 1) {
+    #The top level has no container
+    ok $Data::Walk::type, undef;
+    #Hence no type for container
+    ok $Data::Walk::container, undef;
+  }
+}, $hash, $arr;
+
+walk sub {
+  if ($Data::Walk::depth == 1) {
+    #The top level has no container
+    ok $Data::Walk::type, undef;
+    #Hence no type for container
+    ok $Data::Walk::container, undef;
+  }
+}, 1, $hash, $arr;

I have moved Data-Walk to github: https://github.com/gflohr/Data-Walk

Do you want to create a pull request? That probably gives better documentation. Otherwise, I can also jsut apply your patch.

Ok, I'll create a pull request.