The initial revision of an imported post goes missing

[johnbillion]

There are two problems relating to revisions when making a change to an imported post.

1. The first change does not cause the Revisions meta box to appear. A second change is required.
2. The first change gets "lost" and appears as if it was part of the first version of the post.

Steps to reproduce:

• Import a published post
• Make a change to it
• Observe that the "Revisions" meta box does not show up even after reloading the editing screen
• Make a second change to the post
• Click the "2 Revisions" link and observe that the second revision is recorded correctly, but that the first revision shows the entire contents of the post being added. The first change made "disappears" as it's incorrectly included in the entire contents of the first revision.

I think the root cause here is that imported posts do not create an initial revision.

A possible solution might be to create an initial revision at the point where a user makes a change to a post and there isn't an existing revision.

I assume this can also be reproduced by deleting all the revisions from your database and then making changes to a post.