'guid' not properly escaped

[meloniq]

Probably related issues: #18274 #19248

'guid' being saved in database not properly escaped, example:
http://www.wordpress.dev/?post_type=changeset&p=57 , see the ampersand encode &
It supposed to be & or at least &

Once 'auto-draft' saved, 'guid' is correct: http://www.wordpress.dev/?post_type=changeset&p=57

Once post is saved as 'draft' or published (triggered 'update post' on auto-draft), 'guid' gets malformed.

Source of issue: inappropriate usage of get_post_field() function in the wp_insert_post()

get_post_field() defaults to 'display' context, we not specify context while obtaining field, and in the wp_insert_post() we are not going to display it anywhere, just get, check, and save again, correct?

Attached patch adds the 'raw' context to usage of get_post_field() with 'guid'

adds 'raw' context to get_post_field() call for 'guid' field

Introduced in [6593]. Triggered by the introduction of custom post types in 2.9, since their permalinks can contain an ampersand.

guid-context.patch​ seems good. Other get_post_field() instances in wp_insert_post() should probably use 'raw' context too.

Related: #13555

these are all marked 3.7-early

This is old and there is a concern there are other potential mines in wp_insert_post() as well.

I'm also concerned about tests for this.