Fixing dereferencing bug in is_string

Build.PL

@@ -1,5 +1,5 @@
 
-# This file was automatically generated by Dist::Zilla::Plugin::ModuleBuild v5.039.
+# This file was automatically generated by Dist::Zilla::Plugin::ModuleBuild v5.041.
 use strict;
 use warnings;
 
@@ -15,7 +15,7 @@ my %module_build_args = (
   },
   "dist_abstract" => "a data toolkit",
   "dist_author" => [
-    "Nicolas Steenlant, C<< <nicolas.steenlant at ugent.be> >>"
+    "Nicolas Steenlant <nicolas.steenlant\@ugent.be>"
   ],
   "dist_name" => "Catmandu",
   "dist_version" => "0.9502",
@@ -27,7 +27,7 @@ my %module_build_args = (
   },
   "recursive_test_files" => 1,
   "requires" => {
-    "App::Cmd" => "0.326",
+    "App::Cmd" => "0.33",
     "CGI::Expand" => "2.02",
     "Clone" => "0.31",
     "Config::Onion" => "1.004",

README.md

@@ -10,8 +10,8 @@ Catmandu::Introduction - a Catmandu HOW TO
 
 # Introduction
 
-Catmandu is a data processing toolkit developed as part of the [LibreCat](http://librecat.org) project. 
-Catmandu provides a command line client and a suite of tools to ease the import, storage, retrieval, 
+Catmandu is a data processing toolkit developed as part of the [LibreCat](http://librecat.org) project.
+Catmandu provides a command line client and a suite of tools to ease the import, storage, retrieval,
 export and transformation of data. For instance, to transform a CSV file into JSON use the
 command:
 
@@ -46,7 +46,7 @@ One can also work on deeply nested data. E.g. create a deeply nested data struct
 In this example we moved the field 'title' into the field 'my', which contains a (sub)field 'deeply',
 which contains a (sub)field 'nested'.
 
-Catmandu was created by librarians for librarians. We process a lot of metadata especially 
+Catmandu was created by librarians for librarians. We process a lot of metadata especially
 library metadata in formats such as MARC, MAB2 and MODS. With the following command we can extract
 data from a marc record and to store it into the title field:
 
@@ -83,7 +83,7 @@ Run this (on Linux) by setting the executable bit:
      $ chmod 755 myfix.fix
      $ ./myfix.fix
 
-To experiment with the Fix language you can also run the catmandu Fix interpreter in an 
+To experiment with the Fix language you can also run the catmandu Fix interpreter in an
 interactive mode:
 
      $ catmandu run
@@ -95,12 +95,12 @@ interactive mode:
      ...
      fix >
 
-Catmandu contains many powerfull fixes. Visit [http://librecat.org/Catmandu/#fixes-cheat-sheet](http://librecat.org/Catmandu/#fixes-cheat-sheet) to get 
+Catmandu contains many powerfull fixes. Visit [http://librecat.org/Catmandu/#fixes-cheat-sheet](http://librecat.org/Catmandu/#fixes-cheat-sheet) to get
 an overview what is possible.
 
 # Documentation
 
-For more information read our [documentation pages](http://librecat.org/Catmandu/) 
+For more information read our [documentation pages](http://librecat.org/Catmandu/)
 and [blog](https://librecatproject.wordpress.com/)
 for a complete introduction and update into all Catmandu features.
 
@@ -109,12 +109,12 @@ day introduction into the UNIX command line and Catmandu:
 
 [https://librecatproject.wordpress.com/2014/12/01/day-1-getting-catmandu/](https://librecatproject.wordpress.com/2014/12/01/day-1-getting-catmandu/)
 
-If you need extra training, our developers regulary host workshops at library 
+If you need extra training, our developers regulary host workshops at library
 conferences and events: [http://librecat.org/events.html](http://librecat.org/events.html)
 
 # Installation
 
-There are several ways to get a working version of Catmandu on your computer. 
+There are several ways to get a working version of Catmandu on your computer.
 For a quick and demo installation visit our [blog](https://librecatproject.wordpress.com/get-catmandu/)
 where a VirtualBox image is available containing all the Catmandu modules, including
 ElasticSearch and MongoDB.
@@ -128,19 +128,19 @@ On our [website](http://librecat.org/Catmandu/) we provide installation instruct
     * OpenBSD
     * Windows
 
-and even a generic installation using [Docker](https://www.docker.com/).
+and even a generic installation using [Docker](https://www.docker.com/): [https://hub.docker.com/r/librecat/catmandu/](https://hub.docker.com/r/librecat/catmandu/).
 
 # Open Source
 
-Catmandu software published at https://github.com/LibreCat/Catmandu is free software without warranty, liabilities 
-or support; you can redistribute it and/or modify it under the terms of the GNU General Public License as 
-published by the Free Software Foundation; either version 2 or any later version. Every contributor is free 
+Catmandu software published at https://github.com/LibreCat/Catmandu is free software without warranty, liabilities
+or support; you can redistribute it and/or modify it under the terms of the GNU General Public License as
+published by the Free Software Foundation; either version 2 or any later version. Every contributor is free
 to state her/his copyright.
 
 # Developers & Support
 
 Catmandu has a very active international developer community. We welcome all feedback, bug reports and
-feature enhancement. 
+feature enhancement.
 
 Join our mailing list to receive more information:  `librecat-dev@librecat.org`
 
@@ -150,10 +150,10 @@ Catmandu packages!
 # Kudos
 
 Catmandu is created in a cooperation with many developers world wide. Without them this project isn't possible.
-We would like to thank our core maintainer: Nicolas Steenlant and all contributors: Christian Pietsch , 
-Dave Sherohman , Friedrich Summann , Jakob Voss , Johann Rolschewski  , Jorgen Eriksson  , Magnus Enger , 
-Maria Hedberg , Mathias Loesch , Najko Jahn , Nicolas Franck , Patrick Hochstenbach , Petra Kohorst  , 
-Snorri Briem , Upasana Shukla and Vitali Peil 
+We would like to thank our core maintainer: Nicolas Steenlant and all contributors: Christian Pietsch ,
+Dave Sherohman , Friedrich Summann , Jakob Voss , Johann Rolschewski  , Jorgen Eriksson  , Magnus Enger ,
+Maria Hedberg , Mathias Loesch , Najko Jahn , Nicolas Franck , Patrick Hochstenbach , Petra Kohorst  ,
+Snorri Briem , Upasana Shukla and Vitali Peil
 
 # SEE ALSO
 

cpanfile

@@ -8,7 +8,7 @@ on 'test', sub {
   requires 'Log::Any::Test', '1.03';
 };
 
-requires 'App::Cmd', '0.326';
+requires 'App::Cmd', '0.33';
 requires 'CGI::Expand', '2.02';
 requires 'Clone', '0.31';
 requires 'Config::Onion', '1.004';

lib/Catmandu/Cmd/data.pm

@@ -112,4 +112,4 @@ __END__
 
 Catmandu::Cmd::data - store, index, search, import, export or convert objects
 
-=end
+=cut

lib/Catmandu/Util.pm

@@ -467,7 +467,7 @@ sub is_value {
 
 sub is_string {
     no warnings 'uninitialized';
-    return !ref($_[0]) && ref(\$_[0]) ne 'GLOB' && length($_[0]) > 0;
+    return defined($_[0]) && !ref($_[0]) && ref(\$_[0]) ne 'GLOB' && length($_[0]) > 0;
 }
 
 sub is_number {