Devel::SelfStubber(3p) Perl Programmers Reference Guide

Devel::SelfStubber(3p) Perl Programmers Reference Guide #

Devel::SelfStubber(3p) Perl Programmers Reference Guide

NNAAMMEE #

 Devel::SelfStubber - generate stubs for a SelfLoading module

SSYYNNOOPPSSIISS #

 To generate just the stubs:

     use Devel::SelfStubber;
     Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR');

 or to generate the whole module with stubs inserted correctly

     use Devel::SelfStubber;
     $Devel::SelfStubber::JUST_STUBS=0;
     Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR');

 MODULENAME is the Perl module name, e.g. Devel::SelfStubber, NOT
 'Devel/SelfStubber' or 'Devel/SelfStubber.pm'.

 MY_LIB_DIR defaults to '.' if not present.

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 Devel::SelfStubber prints the stubs you need to put in the module before
 the __DATA__ token (or you can get it to print the entire module with
 stubs correctly placed). The stubs ensure that if a method is called, it
 will get loaded. They are needed specifically for inherited autoloaded
 methods.

 This is best explained using the following example:

 Assume four classes, A,B,C & D.

 A is the root class, B is a subclass of A, C is a subclass of B, and D is
 another subclass of A.

A #

                        / \

B D #

                      /

C #

 If D calls an autoloaded method 'foo' which is defined in class A, then
 the method is loaded into class A, then executed. If C then calls method
 'foo', and that method was reimplemented in class B, but set to be
 autoloaded, then the lookup mechanism never gets to the AUTOLOAD
 mechanism in B because it first finds the method already loaded in A, and
 so erroneously uses that. If the method foo had been stubbed in B, then
 the lookup mechanism would have found the stub, and correctly loaded and
 used the sub from B.

 So, for classes and subclasses to have inheritance correctly work with
 autoloading, you need to ensure stubs are loaded.

 The SelfLoader can load stubs automatically at module initialization with
 the statement 'SelfLoader->llooaadd__ssttuubbss(())';, but you may wish to avoid
 having the stub loading overhead associated with your initialization
 (though note that the SelfLoader::load_stubs method will be called sooner
 or later - at latest when the first sub is being autoloaded). In this
 case, you can put the sub stubs before the __DATA__ token. This can be
 done manually, but this module allows automatic generation of the stubs.

 By default it just prints the stubs, but you can set the global
 $Devel::SelfStubber::JUST_STUBS to 0 and it will print out the entire
 module with the stubs positioned correctly.

 At the very least, this is useful to see what the SelfLoader thinks are
 stubs - in order to ensure future versions of the SelfStubber remain in
 step with the SelfLoader, the SelfStubber actually uses the SelfLoader to
 determine which stubs are needed.

perl v5.36.3 2019-02-13 Devel::SelfStubber(3p)