Bleach 6.0.0 release and deprecation

What is it?

Bleach is a Python library for sanitizing and linkifying text from untrusted sources for safe usage in HTML.

Bleach v6.0.0 released!

Bleach 6.0.0 cleans up some issues in linkify and with the way it uses html5lib so it's easier to reason about. It also adds support for Python 3.11 and cleans up the project infrastructure.

There are several backwards-incompatible changes, hence the 6.0.0 version.

https://bleach.readthedocs.io/en/latest/changes.html#version-6-0-0-january-23rd-2023

I did some rough testing with a corpus of Standup messages data and it looks like bleach.clean is slightly faster with 6.0.0 than 5.0.0.

Using Python 3.10.9:

• 5.0.0: bleach.clean on 58,630 items 10x: minimum 2.793s

• 6.0.0: bleach.clean on 58,630 items 10x: minimum 2.304s

The other big change 6.0.0 brings with it is that it's now deprecated.

Bleach is deprecated

Bleach sits on top of html5lib which is not actively maintained. It is increasingly difficult to maintain Bleach in that context and I think it's nuts to build a security library on top of a library that's not in active development.

Over the years, we've talked about other options:

1. find another library to switch to

2. take over html5lib development

3. fork html5lib and vendor and maintain our fork

4. write a new HTML parser

5. etc

With the exception of option 1, they greatly increase the scope of the work for Bleach. They all feel exhausting to me.

Given that, I think Bleach has run its course and this journey is over.

What happens now?

Possibilities:

1. Pass it to someone else?

   No, I won't be passing Bleach to someone else to maintain. Bleach is a security-related library, so making a mistake when passing it to someone else would be a mess. I'm not going to do that.

2. Switch to an alternative?

   I'm not aware of any alternatives to Bleach. I don't plan to work on coordinating the migration for everyone from Bleach to something else.

3. Oh my goodness--you're leaving us with nothing?

   Sort of.

I'm going to continue doing minimal maintenance:

1. security updates

2. support for new Python versions

3. fixes for egregious bugs (begrudgingly)

I'll do that for at least a year. At some point, I'll stop doing that, too.

I think that gives the world enough time for either something to take Bleach's place, or for the sanitizing web api to kick in, or for everyone to come to the consensus that they never really needed Bleach in the first place.

Thanks!

Many thanks to Greg who I worked with on Bleach for a long while and maintained Bleach for several years. Working with Greg was always easy and his reviews were thoughtful and spot-on.

Many thanks to Jonathan who, over the years, provided a lot of insight into how best to solve some of Bleach's more squirrely problems.

Many thanks to Sam who was an indispensible resource on HTML parsing and sanitizing text in the context of HTML.

Where to go for more

For more specifics on this release, see here: https://bleach.readthedocs.io/en/latest/changes.html#version-6-0-0-january-23rd-2023

Documentation and quickstart here: https://bleach.readthedocs.io/en/latest/

Source code and issue tracker here: https://github.com/mozilla/bleach