Upgrading Genshi


1   Upgrading from Genshi 0.5.x to 0.6.x

1.1   Required Python Version

Support for Python 2.3 has been dropped in this release. Python 2.4 is now the minimum version of Python required to run Genshi.

The XPath engine has been completely overhauled for this version. Some patterns that previously matched incorrectly will no longer match, and the other way around. In such cases, the XPath expressions need to be fixed in your application and templates.

2   Upgrading from Genshi 0.4.x to 0.5.x

2.1   Error Handling

The default error handling mode has been changed to "strict". This means that accessing variables not defined in the template data will now generate an immediate exception, as will accessing object attributes or dictionary keys that don't exist. If your templates rely on the old lenient behavior, you can configure Genshi to use that instead. See the documentation for details on how to do that. But be warned that lenient error handling may be removed completely in a future release.

2.2   Match Template Processing

There has also been a subtle change to how py:match templates are processed: in previous versions, all match templates would be applied to the content generated by the matching template, and only the matching template itself was applied recursively to the original content. This behavior resulted in problems with many kinds of recursive matching, and hence was changed for 0.5: now, all match templates declared before the matching template are applied to the original content, and match templates declared after the matching template are applied to the generated content. This change should not have any effect on most applications, but you may want to check your use of match templates to make sure.

2.3   Text Templates

Genshi 0.5 introduces a new, alternative syntax for text templates, which is more flexible and powerful compared to the old syntax. For backwards compatibility, this new syntax is not used by default, though it will be in a future version. It is recommended that you migrate to using this new syntax. To do so, simply rename any references in your code to TextTemplate to NewTextTemplate. To explicitly use the old syntax, use OldTextTemplate instead, so that you can be sure you'll be using the same language when the default in Genshi is changed (at least until the old implementation is completely removed).

2.4   Markup Constructor

The Markup class no longer has a specialized constructor. The old (undocumented) constructor provided a shorthand for doing positional substitutions. If you have code like this:

Markup('<b>%s</b>', name)

You must replace it by the more explicit:

Markup('<b>%s</b>') % name

2.5   Template Constructor

The constructor of the Template class and its subclasses has changed slightly: instead of the optional basedir parameter, it now expects an (also optional) filepath parameter, which specifies the absolute path to the template. You probably aren't using those constructors directly, anyway, but using the TemplateLoader API instead.

3   Upgrading from Genshi 0.3.x to 0.4.x

The modules genshi.filters and genshi.template have been refactored into packages containing multiple modules. While code using the regular APIs should continue to work without problems, you should make sure to remove any leftover traces of the files filters.py and template.py in the genshi package on the installation path (including the corresponding .pyc files). This is not necessary when Genshi was installed as a Python egg.

Results of evaluating template expressions are no longer implicitly called if they are callable. If you have been using that feature, you will need to add the parenthesis to actually call the function.

Instances of genshi.core.Attrs are now immutable. Filters manipulating the attributes in a stream may need to be updated. Also, the Attrs class no longer automatically wraps all attribute names in QName objects, so users of the Attrs class need to do this themselves. See the documentation of the Attrs class for more information.

4   Upgrading from Markup

Prior to version 0.3, the name of the Genshi project was "Markup". The name change means that you will have to adjust your import statements and the namespace URI of XML templates, among other things:

Furthermore, due to the inclusion of a text-based template language, the class:


has been renamed to:


If you've been using the Template class directly, you'll need to update your code (a simple find/replace should do—the API itself did not change).