[wp-hackers] Unique permalinks vs. unique post slugs

[Austin Matzko]

On Sun, Dec 14, 2008 at 4:03 PM, scribu <scribu at gmail.com> wrote:
> I want to be able to have these two URLs at the same time:
>
> http://example.com/cat-slug/post-slug.html
> http://example.com/other-cat-slug/post-slug.html
>
> The ideea is that currently I can't have the same post slug for 2 or
> more posts, even if the permalink structure would allow it. Where
> should I start looking to get it done?

Check into the 'wp_insert_post_data' filter, which gets all the post
data including the post slug, right after the post slug has been
incremented but before it's actually updated in the database.