PHP compatibility fixes

[peterwilsoncc]

Summary

This includes various PHP compatibly fixes both for PHP 8.4 and to ensure PHP 7.4 compatibility.

This targets the 6.0.0 release branch.

Details

• PHP 7.4: Removes mixed type declarations to maintain support for PHP 7.4 (the current WP & Woo minimum)
• PHP 8.1+: Use modern default flags for htmlspecialchars().
• PHP 8.4: Implicitly marking a parameter as nullable is deprecated since PHP 8.4 (test suite, follow up to Explicitly mark parameters as nullable #788)
• PHPCS Sniffs: Ignores conditional use of WeakMap in Dynamic_Props class

UI Changes

N/A

QA

• Code Review

Setup

List any configuration requirements for testing

• This setting is configured
• Taxes are enabled

Before merge

• I have confirmed these changes in each supported minor WooCommerce version

[peterwilsoncc]

@agibson-godaddy Are you able to review this for the 6.0.0 release? I don't have permission to request reviews via GitHub, sorry.

[agibson-godaddy]

@peterwilsoncc I will take a look as soon as I can -- thanks for the PR! Will be quite busy over the next week or two but will leave this notification unread to remind me as soon as I have time. 🙏

[ajaynes-godaddy]

Looks pretty good, nothing jumping out at me.

Just noting for anybody watching at home that the htmlspecialchars() changes are essentially just setting the PHP 8.1+ default flags as a back-compat measure.

[agibson-godaddy]

LGTM! Thanks for the contribution. :)

[peterwilsoncc]

Thanks @agibson-godaddy, Do you need to to create a PR targeting the default branch or will you cherry pick to that as part of the release process?

[agibson-godaddy]

@peterwilsoncc Sorry not sure if I'm understanding your question. Your changes have been merged into our release branch here: #787

That branch will eventually be merged into default/master branch. After it does we'll then create a new release tag.

[peterwilsoncc]

Thanks Ashley, that answers my question.