Recent change breaks transformers that modify DOM

[zetter]

Thanks for the quick release of 4.6.3 to fix the vulnerability.

I upgraded the sanitize gem on a project I'm working on and found that an integration test was failing. I tracked down the cause of the break to a 4.6.2 change to optimize the memory usage of sanitize.

Previously transformers could make changes to the DOM and other transformers would work on the updated DOM. One of the changes to optimize memory usage caches the name of the DOM node between transformers so this is no longer the case.

I've provided a test case and possible fix by removing this particular memory optimization.

My project's use case is similar to the test- using transformers to change the name of a HTML tag. I was worried that we might be using sanitize in an unusual and unsupported way, but looking at the readme it sounds like this is an expected use of transformers:

Any changes made to the current node or to the document will be reflected instantly in the document and passed on to subsequently called transformers and to Sanitize itself.

If you think the way the transformer is written is surprising and there is a better way, please let me know.

Thanks for your time

[janklimo]

Thank you for catching that @zetter. I wasn't aware people use transformers to change node names,
but it looks like a perfectly valid use case, so the change I introduced in 4.6.2 in transform_node! might have to be reverted.

[rgrove]

@zetter Good catch! I don't think that's a common use case, but it's definitely one Sanitize is meant to support. I've merged your fix and test case and released 4.6.4. Thanks!

Fixed in 71d84a8