# Python-Markdown 3.0 Release Notes

We are pleased to release Python-Markdown 3.0 which adds a few new features and fixes various bugs and deprecates various old features. See the list of changes below for details.

Python-Markdown version 3.0 supports Python versions 2.7, 3.4, 3.5, 3.6, 3.7, PyPy and PyPy3.

## Backwards-incompatible changes

### `enable_attributes` keyword deprecated

The `enable_attributes` keyword is deprecated in version 3.0 and will be ignored. Previously the keyword was `True` by default and enabled an undocumented way to define attributes on document elements. The feature has been removed from version 3.0. As most users did not use the undocumented feature, it should not affect most users. For the few who did use the feature, it can be enabled by using the Legacy Attributes extension.

### `smart_emphasis` keyword and `smart_strong` extension deprecated

The `smart_emphasis` keyword is deprecated in version 3.0 and will be ignored. Previously the keyword was `True` by default and caused the parser to ignore middle-word emphasis. Additionally, the optional `smart_strong` extension provided the same behavior for strong emphasis. Both of those features are now part of the default behavior, and the Legacy Emphasis extension is available to disable that behavior.

### `output_formats` simplified to `html` and `xhtml`.

The `output_formats` keyword now only accepts two options: `html` and `xhtml` Note that if `(x)html1`, `(x)html4` or `(x)html5` are passed in, the number is stripped and ignored.

### `safe_mode` and `html_replacement_text` keywords deprecated

Both `safe_mode` and the associated `html_replacement_text` keywords are deprecated in version 3.0 and will be ignored. The so-called “safe mode” was never actually “safe” which has resulted in many people having a false sense of security when using it. As an alternative, the developers of Python-Markdown recommend that any untrusted content be passed through an HTML sanitizer (like Bleach) after being converted to HTML by markdown. In fact, Bleach Whitelist provides a curated list of tags, attributes, and styles suitable for filtering user-provided HTML using bleach.

If your code previously looked like this:

    html = markdown.markdown(text, safe_mode=True)

Then it is recommended that you change your code to read something like this:

    import bleach
    from bleach_whitelist import markdown_tags, markdown_attrs
    html = bleach.clean(markdown.markdown(text), markdown_tags, markdown_attrs)

If you are not interested in sanitizing untrusted text, but simply desire to escape raw HTML, then that can be accomplished through an extension which removes HTML parsing:

    from markdown.extensions import Extension

    class EscapeHtml(Extension):
        def extendMarkdown(self, md):
            md.preprocessors.deregister('html_block')
            md.inlinePatterns.deregister('html')

    html = markdown.markdown(text, extensions=[EscapeHtml()])

As the HTML would not be parsed with the above Extension, then the serializer will escape the raw HTML, which is exactly what happened in previous versions with `safe_mode="escape"`.

### Positional arguments deprecated

Positional arguments on the `markdown.Markdown()` class are deprecated as are all except the `text` argument on the `markdown.markdown()` wrapper function. Using positional arguments will raise an error. Only keyword arguments should be used. For example, if your code previously looked like this:

    html = markdown.markdown(text, [SomeExtension()])

Then it is recommended that you change it to read something like this:

    html = markdown.markdown(text, extensions=[SomeExtension()])

Note

This change is being made as a result of deprecating `"safe_mode"` as the `safe_mode` argument was one of the positional arguments. When that argument is removed, the two arguments following it will no longer be at the correct position. It is recommended that you always use keywords when they are supported for this reason.

### Extension name behavior has changed

In previous versions of Python-Markdown, the built-in extensions received special status and did not require the full path to be provided. Additionally, third party extensions whose name started with `"mdx_"` received the same special treatment. This is no longer the case.

Support has been added for extensions to define an entry point. An entry point is a string name which can be used to point to an `Extension` class. The built-in extensions now have entry points which match the old short names. And any third-party extensions which define entry points can now get the same behavior. See the documentation for each specific extension to find the assigned name.

If an extension does not define an entry point, then the full path to the extension must be used. See the documentation for a full explanation of the current behavior.

### Extension configuration as part of extension name deprecated

The previously documented method of appending the extension configuration options as a string to the extension name is deprecated and will raise an error. The `extension_configs` keyword should be used instead. See the documentation for a full explanation of the current behavior.

### HeaderId extension deprecated

The HeaderId Extension is deprecated and will raise an error if specified. Use the Table of Contents Extension instead, which offers most of the features of the HeaderId Extension and more (support for meta data is missing).

Extension authors who have been using the `slugify` and `unique` functions defined in the HeaderId Extension should note that those functions are now defined in the Table of Contents extension and should adjust their import statements accordingly (`from markdown.extensions.toc import slugify, unique`).

### Homegrown `OrderedDict` has been replaced with a purpose-built `Registry`

All processors and patterns now get “registered” to a Registry. A backwards compatible shim is included so that existing simple extensions should continue to work. A `DeprecationWarning` will be raised for any code which calls the old API.

### Markdown class instance references.

Previously, instances of the `Markdown` class were represented as any one of `md`, `md_instance`, or `markdown`. This inconsistency made it difficult when developing extensions, or just maintaining the existing code. Now, all instances are consistently represented as `md`.

The old attributes on class instances still exist, but raise a `DeprecationWarning` when accessed. Also on classes where the instance was optional, the attribute always exists now and is simply `None` if no instance was provided (previously the attribute would not exist).

### `markdown.util.isBlockLevel` deprecated

The `markdown.util.isBlockLevel` function is deprecated and will raise a `DeprecationWarning`. Instead, extensions should use the `isBlockLevel` method of the `Markdown` class instance. Additionally, a list of block level elements is defined in the `block_level_elements` attribute of the `Markdown` class which extensions can access to alter the list of elements which are treated as block level elements.

### `md_globals` keyword deprecated from extension API

Previously, the `extendMarkdown` method of a `markdown.extensions.Extension` subclasses accepted an `md_globals` keyword, which contained the value returned by Python’s `globals()` built-in function. As all of the configuration is now held within the `Markdown` class instance, access to the globals is no longer necessary and any extensions which expect the keyword will raise a `DeprecationWarning`. A future release will raise an error.

### `markdown.version` and `markdown.version_info` deprecated

Historically, version numbers were acquired via the attributes `markdown.version` and `markdown.version_info`. Moving forward, a more standardized approach is being followed and versions are acquired via the `markdown.__version__` and `markdown.__version_info__` attributes. The legacy attributes are still available to allow distinguishing versions between the legacy Markdown 2.0 series and the Markdown 3.0 series, but in the future the legacy attributes will be removed.

### Added new, more flexible `InlineProcessor` class

A new `InlineProcessor` class handles inline processing much better and allows for more flexibility. The new `InlineProcessor` classes no longer utilize unnecessary pretext and post-text captures. New class can accept the buffer that is being worked on and manually process the text without regular expressions and return new replacement bounds. This helps us to handle links in a better way and handle nested brackets and logic that is too much for regular expression.

## New features

The following new features have been included in the release:

- A new testing framework is included as a part of the Markdown library, which can also be used by third party extensions.

- A new `toc_depth` parameter has been added to the Table of Contents Extension.

- A new `toc_tokens` attribute has been added to the Markdown class by the Table of Contents Extension, which contains the raw tokens used to build the Table of Contents. Users can use this to build their own custom Table of Contents rather than needing to parse the HTML available on the `toc` attribute of the Markdown class.

- When the Table of Contents Extension is used in conjunction with the Attribute Lists Extension and a `data-toc-label` attribute is defined on a header, the content of the `data-toc-label` attribute is now used as the content of the Table of Contents item for that header.

- Additional CSS class names can be appended to Admonitions.