WXR Export should allow for plugins (or core) to filter what is exported

[westi]

Core currently has a "hack" to filter our the _edit_lock post_meta data and no way for a plugin to filter out things which don't make sense to be exported.

We should have a filter which allows for this filtering to be done by core and plugins without a "hack"

[nacin]

Sounds like a good argument for an $args array at the end of register_meta().

[westi]

Add a filter and use it in core.

[westi]

Replying to nacin:

Sounds like a good argument for an $args array at the end of register_meta().

I guess we could rework the filter and have another argument of register_meta instead which does something similar to the protected meta and hooks a function onto a key name based filter instead of a generic one.

[nacin]

Per IRC: Let's start with the filter for 3.3. The improvements to meta registering may be nice in the future, but also can feel over-abstracted.

[nacin]

In [19233]:

Add wxr_export_skip_postmeta filter for skipping postmeta in exports. props westi, fixes #18280.