Improve error handling when converting classic to block menus

[dlh01]

What?

See #52481. Addresses some errors that can occur when Gutenberg_Navigation_Fallback::create_classic_menu_fallback() calls Gutenberg_Classic_To_Block_Menu_Converter::convert().

Why?

To avoid unexpected behavior or errors resulting from incorrect type handling.

How?

Improving type-checking and returning types consistent with the documentation

[draganescu]

These updates make sense to me 🚀

[getdave]

Looks good. Thanks for spotting these.

Will need a complementary backport PR to WP Core for WP 6.3.

@dlh01 Are you in a position to take that on?

[spacedmonkey]

Should this return a WP_error object?

[getdave]

It's also got me thinking. Any changes here will possible effect the fallback handling code so we'd need to check there.

I'd hope if the tests aren't failing it's all ok but it's entirely possible there isn't 100% coverage 🤔

[getdave]

Actually I don't think this should be an error. That's because we have converted the menu but it was just empty. That doesn't make it invalid. The conversion was a success.

We're just exiting early to avoid running the "to_blocks" code.

Later on we throw an error if the conversion to blocks fails because that's a true "error".

[dlh01]

@getdave Sure, I think I can do that. Is there anything more to it than filing a core PR with the same changes?

[getdave]

@getdave Sure, I think I can do that. Is there anything more to it than filing a core PR with the same changes?

That would be great. Thank you.

Yes you raise a Core PR with the same changes in the equivalent files. And you need a Trac ticket.

[dlh01]

Done in https://core.trac.wordpress.org/ticket/58823 and WordPress/wordpress-develop#4858. Thanks!

[ramonjd]

Looks like the failing PHP tests are related:

There was 1 failure:

1) Gutenberg_Classic_To_Block_Menu_Converter_Test::test_returns_empty_array_for_menus_with_no_items
Result should be empty array.
Failed asserting that '' is of type "array".

/var/www/html/wp-content/plugins/gutenberg/phpunit/class-gutenberg-classic-to-block-menu-converter-test.php:211
phpvfscomposer:///var/www/html/wp-content/plugins/gutenberg/vendor/phpunit/phpunit/phpunit:106

[dlh01]

https://core.trac.wordpress.org/changeset/56422