WXR Import can generate orphan postmeta entries

[dougal]

There is a bug in the duplicate post detection of the WordPress WXR importer. The creation of postmeta occurs outside of the if branch which detects whether a post is a duplicate. I assume that this is in order to attach additional metadata to the copy of the post already in the database (which could be due to re-starting a previously interrupted import). However, due to the way the code is structured, the $post_id variable is not set in this case, and so the postmeta entries are assigned to post_id=0 (zero).

The solution is to capture the post_id returned from the post_exists() function, and set the $post_id variable in the other branch of the duplicate post test.

[dougal]

Set $post_id properly for duplicate posts

[dougal]

Bump. Would really like a fix for this to go into 2.7.

Can supply WXR files for testing, if needed. Though, all you really need for testing is a WXR that has posts with postmeta entries. Just import the same file more than once to trigger the duplicate detection.

[westi]

(In [8957]) Ensure that post meta is attached to the correct post when importing. Fixes #7707 props dougal.