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6.0 Migration Notes


While there are a number of new features and bug fixes, the only backwards incompatible changes are with SuperFences' custom fences. In an effort to make custom fences more useful, we wanted to be able to pass the Markdown object to the formatters. This gives custom formats access to things like metadata if required.

The format of custom fence formatters already had two different versions: ones without custom options and one with custom options. As adding yet another parameter would cause more complexity behind the scenes, we decided to introduce the breaking change of creating a unified format for formatters with custom options and without. In addition to unifying the format, we also now pass the Markdown object to the formatters as an additional parameter.

While we were breaking custom formats, it seemed like a good time to go ahead and change the defaults for the custom_fences options. Most people who are using SuperFences aren't even using the default, niche flow and sequence custom fences. Instead of hijacking fence names that most people aren't even using, it seemed more appropriate to define no custom fences.

Below are instructions on how to upgrade if you were relying on the either the default settings of custom_fences or if you had written your own custom fence formatters.

  1. If you've written your own custom fence formatters, the number of parameters needed has changed, so you must update your existing formatters. The needed parameters are the same regardless of whether you are using an options validator or not.

    def custom_formatter(source, language, css_class, options, md):
        return string
  2. flow and sequence are no longer defined by default. If you were relying on the default custom fences, you will have to define them manually now. The needed settings are found below:

    extension_configs = {
        "pymdownx.superfences": {
            "custom_fences": [
                    'name': 'flow',
                    'class': 'uml-flowchart',
                    'format': pymdownx.superfences.fence_code_format
                    'name': 'sequence',
                    'class': 'uml-sequence-diagram',
                    'format': pymdownx.superfences.fence_code_format

    If you are attempting to configure these options in a YAML based configuration (like in MkDocs), please see the FAQ to see how to specify function references in YAML.