puppet-lint: fix params_empty_string_assignment

Author: bastelfreak

REFERENCE.md

@@ -783,19 +783,19 @@ Default value: `1800`
 
 ##### <a name="install_args"></a>`install_args`
 
-Data type: `String`
+Data type: `Optional[String[1]]`
 
 Any additional installation arguments that will be supplied when running pip install.
 
-Default value: `''`
+Default value: ``undef``
 
 ##### <a name="uninstall_args"></a>`uninstall_args`
 
-Data type: `String`
+Data type: `Optional[String[1]]`
 
 Any additional arguments that will be supplied when running pip uninstall.
 
-Default value: `''`
+Default value: ``undef``
 
 ##### <a name="log_dir"></a>`log_dir`
 
@@ -1070,11 +1070,11 @@ Default value: ``undef``
 
 ##### <a name="extra_pip_args"></a>`extra_pip_args`
 
-Data type: `String`
+Data type: `Optional[String[1]]`
 
 Extra arguments to pass to pip after the requirements file
 
-Default value: `''`
+Default value: ``undef``
 
 ##### <a name="manage_requirements"></a>`manage_requirements`
 

manifests/pip.pp

@@ -62,8 +62,8 @@
   Boolean                                           $editable       = false,
   Array                                             $environment    = [],
   Array                                             $extras         = [],
-  String                                            $install_args   = '',
-  String                                            $uninstall_args = '',
+  Optional[String[1]]                               $install_args   = undef,
+  Optional[String[1]]                               $uninstall_args = undef,
   Numeric                                           $timeout        = 1800,
   String[1]                                         $log_dir        = '/tmp',
   Array[String]                                     $path           = ['/usr/local/bin','/usr/bin','/bin', '/usr/sbin'],
@@ -127,11 +127,11 @@
   }
 
   # TODO: Do more robust argument checking, but below is a start
-  if ($ensure == absent) and ($install_args != '') {
+  if ($ensure == absent) and $install_args {
     fail('python::pip cannot provide install_args with ensure => absent')
   }
 
-  if ($ensure == present) and ($uninstall_args != '') {
+  if ($ensure == present) and $uninstall_args {
     fail('python::pip cannot provide uninstall_args with ensure => present')
   }
 

manifests/requirements.pp

@@ -36,7 +36,7 @@
   Array                                        $environment            = [],
   Boolean                                      $forceupdate            = false,
   Optional[Stdlib::Absolutepath]               $cwd                    = undef,
-  String                                       $extra_pip_args         = '',
+  Optional[String[1]]                          $extra_pip_args         = undef,
   Boolean                                      $manage_requirements    = true,
   Boolean                                      $fix_requirements_owner = true,
   Stdlib::Absolutepath                         $log_dir                = '/tmp',