FS#1598 Release rc2009-02-06 loads multiple instances of a plugin

Plugins

• 

  2009-02-09 abompard

  In the file inc/parserutils.php line 596:
   $Renderer =& plugin_load('renderer',$rname, true);
  
  The last "true" argument causes a new instance of a plugin to be created each time it's called in the page. This breaks combinations of plugins in the ODT format export, as provided by the odt plugin.
  
  For example, a popular combination is the include plugin and the odt plugin. The included pages are supposed to be included in the odt as they are in the xhtml. When being exported to ODT, the included pages are supposed to call the odt renderer to be rendered as ODT XML. It is not a problem to use a new instance of the ODT renderer to do that, except when the included page tries to add an image, for the following reason : to create the ODT file, the odt plugin uses an instance of ZipLib initialized in the document_start function. When an included page tries to add an image, it calls this ZipLib instance to add the image to the Zip. Since it's a new instance of the ODT renderer, the variable is not initialized, and it causes a PHP error ("Call to a member function on a non-object").
  
  If I remove the last "true" argument in the parserutils.php file, the first instance of the ODT renderer is re-used, and everything works as expected.
  
  And by the way, it worked fine in 2008-05-05, which always reused existing instances.
• 

  2009-02-09 ChrisS

  This was a deliberate change to fix issues where multiple calls to the same plugin renderer can result in plugin variables being overwrittten.  E.g. When a plugin renderer extends the default renderer, a nested second use will result in the current value of the $doc variable being lost.
  
  Is there an alternative that will correct this problem with the ODT renderer whilst still allowing multiple instantiations?
  
  I prefer to try to stick with multiple instantiations because that is the way DokuWiki's parser/renderer behaves.
• 

  2009-02-09 abompard

  > Is there an alternative that will correct this problem with the ODT renderer whilst still allowing multiple instantiations?
  
  I really do need to modify some of the renderer instances variables: included styles, ZipLib instance, mime parts, etc.
  
  I'm attaching a very simple patch to let a plugin declare itself as a "singleton", which would force the re-use of the same instance. This is just a proof of concept, so feel free to rewrite it as needed.
  
  How about this solution ?

  • dokuwiki-singleton.patch text/plain
• 

  2009-02-11 ChrisS

  I've sent Andi a patch adding a new plugin method, isSingleton().  Implement that method and return true to override the second instantiation.  Its benign - ie. a plugin with that method can be used with earlier versions of DokuWiki with no ill effects.
• Related tasks:
  • FS#1603 Incomplete Export of ODT Plugin