Correctly handle siblings_disallowed from spec

[swissspidy]

Summary

Elements like <amp-story> use siblings_disallowed: true to ensure they don't have any sibling elements.

https://github.com/ampproject/amphtml/blob/db9d5dbd9a1b5e21eba496e791829308dbb19c7e/extensions/amp-story/validator-amp-story.protoascii#L104

Due to a bug report for the Web Stories plugin we noticed that the existing sanitizers were not removing any disallowed siblings of <amp-story>

Turns out, this information was not being used at all in bin/amphtml-update.py and AMP_Tag_And_Attribute_Sanitizer.

This PR is an attempt at fixing that.

I had to tweak the Python script a bit to get the generation working again, as Bento has now been removed and also amp-redbull-player was deprecated.

Checklist

• My code is tested and passes existing tests.
• My code follows the Engineering Guidelines (updates are often made to the guidelines, check it out periodically).

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[swissspidy]

No idea why those amp-facebook tests are failing 🤷

The Bento tests and the ones for amp-redbull-player can be removed I suppose.

Any help appreciated.

[thelovekesh]

@swissspidy I think failing tests can be the result of the removal of bento extension from allowed tags. When the expected string is bento optimized (or bento component markup) but bento is not actually present in the allowed tags and attributes, the results of a few tests may differ.

We can re-generate includes/sanitizers/class-amp-allowed-tags-generated.php by not removing bento extensions from bin/amphtml-update.py to check if tests are passing?

[swissspidy]

Hmm I guess, but that's tricky unless I do it manually, because bundles.config.bento.json no longer exists.

Maybe now's simply the time to remove Bento here?

[westonruter]

Hmm I guess, but that's tricky unless I do it manually, because bundles.config.bento.json no longer exists.

Maybe now's simply the time to remove Bento here?

Yes, that should be done. However, that would probably add too much scope to this PR. How about reverting the changes to Bento in bin/amphtml-update.py and includes/sanitizers/class-amp-allowed-tags-generated.php (e.g. via git checkout -p develop -- bin/amphtml-update.py includes/sanitizers/class-amp-allowed-tags-generated.php)?

Then we can update the spec generator and remove Bento in another PR.

[westonruter]

LGTM!