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1 | =head1 NAME |
2 | |
3 | Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst |
4 | |
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5 | =head1 Upgrading to Catalyst 5.80 |
6 | |
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7 | Most applications and plugins should run unaltered on Catalyst 5.80. |
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8 | |
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9 | However, a lot of refactoring work has taken place, and several changes have |
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10 | been made which could cause incompatibilities. If your application or plugin |
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11 | is using deprecated code, or relying on side effects, then you could have |
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12 | issues upgrading to this release. |
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13 | |
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14 | Most issues found with pre-existing components have been easy to |
15 | solve. This document provides a complete description of behavior changes |
16 | which may cause compatibility issues, and of new Catalyst warnings which |
17 | be unclear. |
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18 | |
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19 | If you think you have found an upgrade-related issue which is not covered in |
20 | this document, please email the Catalyst list to discuss the problem. |
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21 | |
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22 | =head1 Moose features |
23 | |
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24 | =head2 Application class roles |
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25 | |
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26 | You can only apply method modifiers after the application's C<< ->setup >> |
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27 | method has been called. This means that modifiers will not work with methods |
28 | which run during the call to C<< ->setup >>. |
29 | |
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30 | See L<Catalyst::Manual::ExtendingCatalyst> for more information about using |
31 | L<Moose> in your applications. |
32 | |
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33 | =head2 Controller actions in Moose roles |
34 | |
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35 | You can use L<MooseX::MethodAttributes::Role> if you want to declare actions |
36 | inside Moose roles. |
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37 | |
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38 | =head2 Using Moose in Components |
39 | |
40 | The correct way to use Moose in a component in a both forward and backwards |
41 | compatible way is: |
42 | |
43 | package TestApp::Controller::Root; |
44 | use Moose; |
45 | BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever |
46 | |
47 | See L<Components which inherit from Moose::Object before Catalyst::Component>. |
48 | |
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49 | =head1 Known backwards compatibility breakages |
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50 | |
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51 | =head2 Applications in a single file |
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52 | |
53 | Applications must be in their own file, and loaded at compile time. This |
8f61d649 |
54 | issue generally only affects the tests of CPAN distributions. Your |
55 | application will fail if you try to define an application inline in a |
56 | block, and use plugins which supply a C< new > method, then use that |
57 | application latter in tests within the same file. |
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58 | |
59 | This is due to the fact that Catalyst is inlining a new method on your |
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60 | application class allowing it to be compatible with Moose. The method |
61 | used to do this changed in 5.80004 to avoid the possibility of reporting |
62 | an 'Unknown Error' if your application failed to compile. |
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63 | |
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64 | =head2 Issues with Class::C3 |
65 | |
8f61d649 |
66 | Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is |
67 | built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This |
68 | replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components |
69 | to resolve methods using C3, rather than the unpredictable dispatch |
70 | order of L<NEXT>. |
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71 | |
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72 | This issue is characterised by your application failing to start due to an |
73 | error message about having a non-linear @ISA. |
74 | |
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75 | The Catalyst plugin most often causing this is |
76 | L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this |
77 | plugin and see issues, then please upgrade your plugins, as it has been |
78 | fixed. Note that Makefile.PL in the distribution will warn about known |
79 | incompatible components. |
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80 | |
81 | This issue can, however, be found in your own application - the only solution is |
82 | to go through each base class of the class the error was reported against, until |
83 | you identify the ones in conflict, and resolve them. |
84 | |
85 | To be able to generate a linear @ISA, the list of superclasses for each |
86 | class must be resolvable using the C3 algorithm. Unfortunately, when |
87 | superclasses are being used as mixins (to add functionality used in your class), |
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88 | and with multiple inheritance, it is easy to get this wrong. |
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89 | |
90 | Most common is the case of: |
91 | |
92 | package Component1; # Note, this is the common case |
93 | use base qw/Class::Accessor::Fast Class::Data::Inheritable/; |
94 | |
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95 | package Component2; # Accidentally saying it this way causes a failure |
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96 | use base qw/Class::Data::Inheritable Class::Accessor::Fast/; |
97 | |
98 | package GoesBang; |
99 | use base qw/Component1 Component2/; |
100 | |
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101 | Any situation like this will cause your application to fail to start. |
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102 | |
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103 | For additional documentation about this issue, and how to resolve it, see |
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104 | L<Class::C3::Adopt::NEXT>. |
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105 | |
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106 | =head2 Components which inherit from Moose::Object before Catalyst::Component |
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107 | |
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108 | Moose components which say: |
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109 | |
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110 | package TestApp::Controller::Example; |
111 | use Moose; |
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112 | extends qw/Moose::Object Catalyst::Component/; |
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113 | |
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114 | to use the constructor provided by Moose, while working (if you do some hacks |
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115 | with the C< BUILDARGS > method), will not work with Catalyst 5.80 as |
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116 | C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails |
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117 | to linearize. |
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118 | |
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119 | The correct way to use Moose in a component in a both forward and backwards |
120 | compatible way is: |
121 | |
122 | package TestApp::Controller::Root; |
123 | use Moose; |
124 | BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever |
125 | |
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126 | Note that the C< extends > declaration needs to occur in a begin block for |
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127 | L<attributes> to operate correctly. |
128 | |
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129 | This way you do not inherit directly from C<Moose::Object> |
130 | yourself. Having components which do not inherit their constructor from |
131 | C<Catalyst::Component> is B<unsupported>, and has never been recommended, |
132 | therefore you're on your own if you're using this technique. You'll need |
133 | to detect the version of Catalyst your application is running, and deal |
134 | with it appropriately. |
135 | |
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136 | You also don't get the L<Moose::Object> constructor, and therefore attribute |
137 | initialization will not work as normally expected. If you want to use Moose |
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138 | attributes, then they need to be made lazy to correctly initialize. |
139 | |
140 | Note that this only applies if your component needs to maintain component |
141 | backwards compatibility for Catalyst versions before 5.71001 - in 5.71001 |
142 | attributes work as expected, and the BUILD method is called normally |
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143 | (although BUILDARGS is not). |
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144 | |
145 | If you depend on Catalyst 5.8, then B<all> Moose features work as expected. |
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146 | |
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147 | You will also see this issue if you do the following: |
148 | |
149 | package TestApp::Controller::Example; |
150 | use Moose; |
151 | use base 'Catalyst::Controller'; |
152 | |
153 | as C< use base > appends to @ISA. |
154 | |
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155 | =head3 use Moose in MyApp |
156 | |
157 | Similar to the above, this will also fail: |
158 | |
159 | package MyApp; |
160 | use Moose; |
161 | use Catalyst qw/ |
162 | ConfigLoader |
163 | /; |
164 | __PACKAGE__->setup; |
165 | |
166 | If you need to use Moose in your application class (e.g. for method modifiers |
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167 | etc.) then the correct technique is: |
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168 | |
169 | package MyApp; |
170 | use Moose; |
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171 | use Catalyst; |
172 | |
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173 | extends 'Catalyst'; |
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174 | |
175 | __PACKAGE__->config( name => 'MyApp' ); |
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176 | __PACKAGE__->setup(qw/ |
177 | ConfigLoader |
178 | /); |
179 | |
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180 | =head2 Anonymous closures installed directly into the symbol table |
181 | |
182 | If you have any code which installs anonymous subroutine references directly |
183 | into the symbol table, you may encounter breakages. The simplest solution is |
184 | to use L<Sub::Name> to name the subroutine. Example: |
185 | |
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186 | # Original code, likely to break: |
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187 | my $full_method_name = join('::', $package_name, $method_name); |
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188 | *$full_method_name = sub { ... }; |
189 | |
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190 | # Fixed Code |
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191 | use Sub::Name 'subname'; |
192 | my $full_method_name = join('::',$package_name, $method_name); |
193 | *$full_method_name = subname $full_method_name, sub { ... }; |
194 | |
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195 | Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and |
196 | install the closure using the appropriate metaclass. Example: |
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197 | |
198 | use Class::MOP; |
199 | my $metaclass = Moose::Meta::Class->initialize($package_name); |
200 | $metaclass->add_method($method_name => sub { ... }); |
201 | |
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202 | =head2 Hooking into application setup |
203 | |
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204 | To execute code during application start-up, the following snippet in MyApp.pm |
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205 | used to work: |
206 | |
207 | sub setup { |
208 | my ($class, @args) = @_; |
209 | $class->NEXT::setup(@args); |
210 | ... # things to do after the actual setup |
211 | } |
212 | |
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213 | With Catalyst 5.80 this won't work anymore, because Catalyst no longer |
214 | uses NEXT.pm for method resolution. The functionality was only ever |
215 | originally operational as L<NEXT> remembers what methods have already |
216 | been called, and will not call them again. |
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217 | |
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218 | Using this now causes infinite recursion between MyApp::setup and |
219 | Catalyst::setup, due to other backwards compatibility issues related to how |
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220 | plugin setup works. Moose method modifiers like C<< before|after|around setup |
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221 | => sub { ... }; >> also will not operate correctly on the setup method. |
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222 | |
223 | The right way to do it is this: |
224 | |
225 | after setup_finalize => sub { |
226 | ... # things to do after the actual setup |
227 | }; |
228 | |
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229 | The setup_finalize hook was introduced as a way to avoid this issue. |
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230 | |
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231 | =head2 Components with a new method which returns false |
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232 | |
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233 | Previously, if you had a component which inherited from Catalyst::COMPONENT, |
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234 | but overrode the new method to return false, then your class's configuration |
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235 | would be blessed into a hash on your behalf, and this would be returned from |
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236 | the COMPONENT method. |
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237 | |
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238 | This behavior makes no sense, and so has been removed. Implementing your own |
239 | C< new > method in components is B<highly> discouraged. Instead, you should |
240 | inherit the new method from Catalyst::Component, and use Moose's BUILD |
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241 | functionality and/or Moose attributes to perform any construction work |
242 | necessary for your class. |
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243 | |
244 | =head2 __PACKAGE__->mk_accessor('meta'); |
245 | |
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246 | Won't work due to a limitation of L<Moose>. This is currently being fixed |
247 | inside Moose. |
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248 | |
249 | =head2 Class::Data::Inheritable side effects |
250 | |
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251 | Previously, writing to a class data accessor would copy the accessor method |
252 | down into your package. |
253 | |
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254 | This behavior has been removed. While the class data is still stored |
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255 | per-class, it is stored on the metaclass of the class defining the accessor. |
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256 | |
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257 | Therefore anything relying on the side effect of the accessor being copied down |
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258 | will be broken. |
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259 | |
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260 | The following test demonstrates the problem: |
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261 | |
262 | { |
263 | package BaseClass; |
264 | use base qw/Class::Data::Inheritable/; |
265 | __PACKAGE__->mk_classdata('foo'); |
266 | } |
267 | |
268 | { |
269 | package Child; |
270 | use base qw/BaseClass/; |
271 | } |
272 | |
273 | BaseClass->foo('base class'); |
274 | Child->foo('sub class'); |
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275 | |
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276 | use Test::More; |
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277 | isnt(BaseClass->can('foo'), Child->can('foo')); |
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278 | |
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279 | =head2 Extending Catalyst::Request or other classes in an ad-hoc manner using mk_accessors |
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280 | |
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281 | Previously, it was possible to add additional accessors to Catalyst::Request |
282 | (or other classes) by calling the mk_accessors class method. |
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283 | |
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284 | This is no longer supported - users should make a subclass of the class whose |
285 | behavior they would like to change, rather than globally polluting the |
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286 | Catalyst objects. |
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287 | |
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288 | =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT |
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289 | |
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290 | Previously, Catalyst's COMPONENT method would delegate to the method on |
291 | the right hand side, which could then delegate back again with |
292 | NEXT. This is poor practice, and in addition, makes no sense with C3 |
293 | method dispatch order, and is therefore no longer supported. |
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294 | |
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295 | If a COMPONENT method is detected in the inheritance hierarchy to the right |
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296 | hand side of Catalyst::Component::COMPONENT, then the following warning |
297 | message will be emitted: |
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298 | |
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299 | There is a COMPONENT method resolving after Catalyst::Component |
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300 | in ${next_package}. |
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301 | |
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302 | The correct fix is to re-arrange your class's inheritance hierarchy so that the |
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303 | COMPONENT method you would like to inherit is the first (left-hand most) |
304 | COMPONENT method in your @ISA. |
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305 | |
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306 | =head1 WARNINGS |
307 | |
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308 | =head2 Actions in your application class |
309 | |
310 | Having actions in your application class will now emit a warning at application |
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311 | startup as this is deprecated. It is highly recommended that these actions are moved |
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312 | into a MyApp::Controller::Root (as demonstrated by the scaffold application |
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313 | generated by catalyst.pl). |
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314 | |
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315 | This warning, also affects tests. You should move actions in your test, |
316 | creating a myTest::Controller::Root, like the following example: |
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317 | |
318 | package MyTest::Controller::Root; |
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319 | |
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320 | use strict; |
321 | use warnings; |
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322 | |
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323 | use parent 'Catalyst::Controller'; |
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324 | |
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325 | __PACKAGE__->config(namespace => ''); |
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326 | |
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327 | sub action : Local { |
328 | my ( $self, $c ) = @_; |
329 | $c->do_something; |
330 | } |
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331 | |
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332 | 1; |
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333 | |
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334 | =head2 ::[MVC]:: naming scheme |
335 | |
336 | Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated |
337 | by catalyst.pl |
338 | |
339 | This is still supported, but it is recommended that you rename your application |
340 | components to Model/View/Controller. |
341 | |
342 | A warning will be issued at application startup if the ::[MVC]:: naming scheme is |
343 | in use. |
344 | |
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345 | =head2 Catalyst::Base |
346 | |
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347 | Any code using L<Catalyst::Base> will now emit a warning; this |
348 | module will be removed in a future release. |
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349 | |
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350 | =head2 Methods in Catalyst::Dispatcher |
351 | |
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352 | The following methods in Catalyst::Dispatcher are implementation |
353 | details, which may change in the 5.8X release series, and therefore their use |
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354 | is highly deprecated. |
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355 | |
356 | =over |
357 | |
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358 | =item tree |
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359 | |
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360 | =item dispatch_types |
c571d2c8 |
361 | |
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362 | =item registered_dispatch_types |
c571d2c8 |
363 | |
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364 | =item method_action_class |
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365 | |
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366 | =item action_hash |
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367 | |
368 | =item container_hash |
369 | |
370 | =back |
371 | |
372 | The first time one of these methods is called, a warning will be emitted: |
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373 | |
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374 | Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name, |
375 | this will be removed in Catalyst 5.9X |
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376 | |
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377 | You should B<NEVER> be calling any of these methods from application code. |
378 | |
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379 | Plugin authors and maintainers whose plugins currently call these methods |
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380 | should change to using the public API, or, if you do not feel the public API |
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381 | adequately supports your use case, please email the development list to |
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382 | discuss what API features you need so that you can be appropriately supported. |
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383 | |
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384 | =head2 Class files with names that don't correspond to the packages they define |
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385 | |
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386 | In this version of Catalyst, if a component is loaded from disk, but no |
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387 | symbols are defined in that component's name space after it is loaded, this |
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388 | warning will be issued: |
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389 | |
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390 | require $class was successful but the package is not defined. |
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391 | |
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392 | This is to protect against confusing bugs caused by mistyping package names, |
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393 | and will become a fatal error in a future version. |
394 | |
395 | Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully |
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396 | supported; this warning is only issued when component file naming does not map |
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397 | to B<any> of the packages defined within that component. |
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398 | |
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399 | =head2 $c->plugin method |
400 | |
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401 | Calling the plugin method is deprecated, and calling it at run time is B<highly |
8dd2f514 |
402 | deprecated>. |
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403 | |
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404 | Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to |
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405 | compose the functionality you need outside of the main application name space. |
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406 | |
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407 | Calling the plugin method will not be supported past Catalyst 5.81. |
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408 | |
7e2ec16e |
409 | =cut |
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410 | |