Remove the translation loading.

[thijsoo]

Context

• Since 6.7 we don't need to add our own translation domain loading.

Summary

This PR can be summarized in the following changelog entry:

• Modernizes how translations of the plugin work by removing the unneeded load_plugin_textdomain() calls.

Relevant technical choices:

• As per the relevant post for WP core, the same goes for load_muplugin_textdomain().. That's why we remove that one as well.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Smoke test our plugin in another language than English and do the same for a multisite install.

mu-plugin use

• In a fresh non-english site, use Yoast SEO as a mu-plugin and gain confirm that non-english translations work. The way you would do that is:
• Install but not activate this RC
• Add a yoast-seo-loader.php in wp-content/mu-plugins with the following code:

 <?php
/**
 * MU-Plugin loader for Yoast SEO.
 * This simply requires the real plugin file from the plugins directory.
 */

$yoast_main = WP_PLUGIN_DIR . '/wordpress-seo/wp-seo.php';

if ( file_exists( $yoast_main ) ) {
    require_once $yoast_main;
}

• In Dashboard->Updates, go and update the translations
• Go to a Yoast admin page and confirm that you see translations.

Translated option defaults

• Now install the RC in a completely fresh site, that's in non-english language. Once you activate it, go to the db and find the wpseo-titles entry
  • Confirm that the entries that contain strings are translated. For example, the title-404-wpseo title is not Page not found but its translation.

Relevant test scenarios

• Changes should be tested with the browser console open
• Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• Changes should be tested on different editors (Default Block/Gutenberg/Classic/Elementor/other)
• Changes should be tested on different browsers
• Changes should be tested on multisite

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

Documentation

• I have written documentation for this change. For example, comments in the Relevant technical choices, comments in the code, documentation on Confluence / shared Google Drive / Yoast developer portal, or other.

Quality assurance

• I have tested this code to the best of my abilities.
• During testing, I had activated all plugins that Yoast SEO provides integrations for.
• I have added unit tests to verify the code works as intended.
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
• I have written this PR in accordance with my team's definition of done.
• I have checked that the base branch is correctly set.

Innovation

• No innovation project is applicable for this PR.
• This PR falls under an innovation project. I have attached the innovation label.
• I have added my hours to the WBSO document.

Fixes #

[coveralls]

Pull Request Test Coverage Report for Build ff91b585ee46a916601f5f9e6cc1e564a5cfe186

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall first build on 496-remove-load_plugin_textdomain-from-all-our-plugins-since-its-now-redundant-for-all-add-ons-too-since-wp-68 at 49.861%

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Totals
Change from base Build 1c98b1bb816ef353eae4ee35766c1370dee834f0:	49.9%
Covered Lines:	17952
Relevant Lines:	36004

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💛 - Coveralls

[igorschoester]

AT 🚫

I got a fatal activating the plugin. We still call this function here.

[leonidasmi]

CR + Acceptance is ✅

[leonidasmi]

As per the relevant dev note, load_muplugin_textdomain() is also not needed anymore. I'm adding a technical decision note in the PR, for future reference (plus some test instructions for it)

[leonidasmi]

Only on a second glance I was able to realize what this was for (aka, being able to have translations available for the translate_defaults() function of wpseo options). I have added an explicit step about it in the test instructions.