users with no posts are not exported

[sillybean]

I just exported a large standalone site and imported into a multisite setup, and I discovered that a number of users who hadn't yet posted anything didn't get moved to the new site.

[duck_]

The arguments against would be that you could potentially be creating a massive export file with all the users and that WXR export files are "not intended to serve as a complete backup of your site".

Though I suppose only users with edit_posts capability and above could be exported or something.

[nacin]

Replying to duck_:

Though I suppose only users with edit_posts capability and above could be exported or something.

That seems like a good idea.

[logiclord]

Users with the ability to edit posts and above can be exported

[logiclord]

all changes to be made in wp-admin/includes/export.php .
We can also specify selective users as mentioned in diff file.

[nacin]

This patch isn't scalable and doesn't use the API properly.

Querying all user IDs in a multisite instance might result in thousands (or millions) of users to loop through. That's a lot of queries. What we could do instead is join the usermeta table and fetch users that are specifically assigned to this blog. (And at that point, we'd probably just use get_users() with a blog ID.)

The logic is also flawed -- we can't make assumptions based on roles. We'd instead need to run user_can() for each user -- which is pretty expensive for so many users. Will take too much memory. The goal here would be one of two things: export any user with a user level <> 0, or export any user tied to the blog in general (including subscribers). If our goal is to include users in export files for now on, then this seems reasonable (except where limited by just too many users).

It should be noted that user level <> 0 is a hack -- normally, we can only check capabilities. Not role names, not user levels. Just when using the API for future patches.

[scribu]

Re user level <> 0: #16714

[logiclord]

Blog id added and !=0 used

[logiclord]

specific capability test. Still needs testing.

[SergeyBiryukov]

Related: #32130

[earnjam]

Authors were not included in the exports until 3.1, so changing the verison.

Also leaving needs-patch because the existing patches don't apply properly and the latest one still uses an approach that won't scale.