Metadata sniffs

[justintadlock]

Warning:

We need sniffs that check metadata. Currently, the theme review team allows themes to have metadata if it is presentational in nature. Some common examples:

• Sidebar position
• Background color
• Layout

However, we do not allow metadata that is non-presentational in nature. Some common examples:

• Video URL
• Gallery shortcode
• User-specific social URLs

This would probably need to be an warning-level notice because we wouldn't be able to know whether the meta is presentational or not via code.

Code would need to check functions:

• add_metadata()
• update_metadata()
• add_post_meta()
• update_post_meta()
• add_user_meta()
• update_user_meta()
• add_comment_meta()
• update_comment_meta()

We could probably check for the delete_*_meta() functions too, but this is probably unnecessary.

Hooks to check:

• attachment_fields_to_edit
• attachment_fields_to_save

Error:

One area we could absolutely check for non-presentational metadata is if a theme has a filter on user_contactmethods. This is only used for adding contact methods to the user profile, which would not be presentational.

[joyously]

And how would this work if the theme integrates a library for that purpose? Is it allowed because the theme isn't doing the work? Or is the library then part of the theme that shouldn't be doing it either?

[justintadlock]

A library included in the theme is still a part of the theme. So, it doesn't matter. The library is irrelevant in this case.

[carolinan]

I suppose we should do the same for custom widgets.

[rinkuyadav999]

Let allow non-presentational metadata.

[carolinan]

There is a branch for this issue-136-non-presentational-meta but it needs testing.
Should this not be combined with other restricted functions?

[dingo-d]

Resolution from the triage: we should add this as a sniff and add info into the requirements. Also, see if there is a chapter for this in the Theme developers handbook and add a chapter there if there isn't.