Reduce usage of `wp_get_theme`

[spacedmonkey]

The function wp_get_theme function returns an instance of WP_Theme instance. Creating an instance of this class uses resources. In many cases this is not needed, as a single property is used. Lowering usage will save CPU cycles.

Trac ticket: https://core.trac.wordpress.org/ticket/57057

[spacedmonkey]

Before

[spacedmonkey]

After

[desrosj]

@spacedmonkey It looks like ​one of the changes needs to be submitted upstream to Gutenberg.

There are definitely some instances where removing wp_get_theme() may be appropriate, and this seems like a great improvement at the surface. But I wonder if there's a better way since this does not address the root problem that creating instances of WP_Theme can be resource intensive. But what about reworking WP_Theme to have a get_instance() method that's called by wp_get_theme() (similar to what is done for posts, terms, comments, etc.) and using the Cache API?

This also feels like a major release change rather than a minor one to me. I'm going to leave it in 6.1.2 for now and will let the folks leading that release make the final call, but I recommend waiting for 6.2 for including this.

[flixos90]

@spacedmonkey Doesn't really need many unit tests, but one unit test to cover the change in supported method parameter value would be useful.

@desrosj For me, most of this is reasonable to land in 6.1.x as it's trivial replacements of wp_get_theme()->get_stylesheet() with get_stylesheet() which is good for performance. However, changing the supported values for a method parameter, despite being backward compatible, strictly speaking would go beyond a 6.1.x. Though I don't have a strong opinion either way.

[spacedmonkey]

@flixos90 Changing the get_user_data_from_wp_global_styles is the biggest change in this patch. If we remove that, I think can commit in 6.1.x.

This is a trival change as it a function replacement and drop-in solution.

[flixos90]

Replying to spacedmonkey:

@flixos90 Changing the get_user_data_from_wp_global_styles is the biggest change in this patch. If we remove that, I think can commit in 6.1.x.

This is a trival change as it a function replacement and drop-in solution.

SGTM. In that case, it doesn't need unit tests either.

[desrosj]

I think if the change to get_user_data_from_wp_global_styles is removed, we could look at including this in 6.1.1.

[spacedmonkey]

@peterwilsoncc @flixos90 @desrosj I have scaled back to the PR, so it just does drop-in replacements of one function to another.

Please review. I have provided before and after numbers.

[spacedmonkey]

Before

[desrosj]

Thanks @spacedmonkey! Looks good. I say let's include this improvement in 6.1.1.

[spacedmonkey]

In 54817:

Themes: Reduce usage of wp_get_theme function.

Calling the wp_get_theme function creates a instance of the WP_Theme class. This can be a performance issue, if all you need is one property of the class instance. This change replaces the usage of wp_get_theme()->get_stylesheet() with get_stylesheet() to improve performance.

Props spacedmonkey, flixos90, peterwilsoncc, desrosj.
Fixes #57057.

[desrosj]

Reopening for backport to 6.1.1.

[desrosj]

In 54818:

Themes: Reduce usage of wp_get_theme function.

Calling the wp_get_theme function creates a instance of the WP_Theme class. This can be a performance issue, if all you need is one property of the class instance. This change replaces the usage of wp_get_theme()->get_stylesheet() with get_stylesheet() to improve performance.

Props spacedmonkey, flixos90, peterwilsoncc, desrosj.
Merges [54817] to the 6.1 branch.
Fixes #57057.

[desrosj]

In 54819:

Themes: Revert one instance of wp_get_theme() from [54817].

Since this specific call to wp_get_theme() is found within wp-includes/blocks, this change will need to be made upstream in the Gutenberg repository.

See #57057.

[desrosj]

In 54820:

Themes: Revert one instance of wp_get_theme() from [54817].

Since this specific call to wp_get_theme() is found within wp-includes/blocks, this change will need to be made upstream in the Gutenberg repository.

Merges [54819] to the 6.1 branch.
See #57057.

Committed

[desrosj]

In 54824:

Coding Standards: Apply spacing changes after composer format.

Follow up to [54817].
See #57057.

[desrosj]

In 54826:

Coding Standards: Apply spacing changes after composer format.

Follow up to [54817].

Merges [54824] to the 6.1 branch.
See #57057.