WordPress import fails to create new users

[yoavf]

When an xml import file contain user names with characters other than [a-z][A-Z], importer still asks if you'd like to import the author.

Problem: Usernames cannot have these characters in them.
The author is not imported, and all posts are mapped to the default user (admin ?)

Possible solutions

1. Do not display the "Import Author" line for those usernames

2. Display error/warning that the user wasn't imported and that posts were mapped to user "XXX"

Or 3., we sanitize the username accordingly.

Punting due to lack of patch.

Saw this investigating #11484.

Nub of the issue is that export files contain display name which is not user_login safe and sanitize_user can strip it down to an empty username.

#11548 - Will remove the ability to create duff users but not yet fix the importer.

(In [12469]) Fix some notices in the importer when importing files from old WordPress versions or not fetching attachments. See #11484.
Ensure that we check that a user is created for the username we specify and otherwise fallback to the current user
See #10319.

That improves this a bit.

Would be great to improve the UX some more in 3.0 to detect the invalid username earlier and offer a better solution that then current fallback.

What is an invalid / a valid username? We could create a validation function then and deal accordingly with valid / invalid usernames as needed.

Replying to hakre:

What is an invalid / a valid username? We could create a validation function then and deal accordingly with valid / invalid usernames as needed.

It gets passed through sanitize_user($user_login, true) so the valid name has to match all the rules there.

The big problem at the moment is what to do when the username has no valid chars in it.

I suspect we should modify the first step to show the usernames which will be created and allow the user to change them if no good.

Something like:

Username in import - Username when imported - Use existing user
דיסוננס קוגניטיבי - imported_user_1 (o) [admin\/]

sanitize_user($user_login, true)

does not support utf8, allowed chars for a wordpress username are:

WPUSERNAME ::= [a-zA-Z0-9 _.@-]+ while duplicate spaces are not allowed

see also #11777

user names als here: #11753

Why not leave the username field empty for those users?
If the users leave that empty, posts will automatically assigned to the first user.
wp30-import-users.diff does that

We should still esc_attr it I think. Looks fine to me though. Might be a little late in the development cycle? I suppose all that would be hurt is that more posts would be mapped to users, instead of to the admin.

(In [15961]) Importer and exporter overhaul, mega props duck.

Exporter overhaul:

• Add author information to export
• Greater usage of slug identifiers
• Don't export auto-drafts, spam comments, or edit lock/last meta keys
• Inline documentation improvements
• Remove filtering for now (@todo)
• Bump WXR version to 1.1, but remain back compat in the importer

Importer overhaul (​http://plugins.trac.wordpress.org/changeset/304249):

• Use an XML parser where available (SimpleXML, XML Parser)
• Proper import support for navigation menus
• Many bug fixes, specifically improvements to category and custom taxonomy handling
• Better author/user mapping

Fixes #5447 #5460 #7400 #7973 #8471 #9237 #10319 #11118 #11144 #11354 #11574 #12685 #13364 #13394 #13453 #13454 #13627 #14306 #14442 #14524 #14750 #15055 #15091 #15108.

See #15197.