Revisions behaviour changed?

@migration #relocate #revisions

Update (July 8)

It appears this is related to a change between 3.5.x and 3.6 of where wp_save_post_revision() is hooked. In 3.5.x, it is hooked on pre_post_update; in 3.6, it is hooked on wp_insert_post. This change (revision 23842) means that behaviour is inconsistent between 3.5.x and 3.6.

Original post (July 5)

Clearly, a team has been working to improve post revisions for 3.6. See trunk/wp-includes/revision.php and this diff of trunk against the 3.5.2 tag.

Up until now, I was running unit tests against 3.5.2. When I tried running them on my own laptop (rather than over SSH to another box), not realizing it was against trunk, the tests failed on this assertion:

/* line 80 */ $this->assertCount( 1, $post_revisions );

I might be wrong here (I need to look at this in more detail), but when I was testing against 3.5.2, the number of revisions after the replacement was 1. When testing against trunk, the number of revisions after the replacement was 2 -- including both the original and URL-replaced post.