get_post_ancestors() now returns false in addition to array()

[dd32]

Under ​3.4, get_post_ancestors() would always return an array, in error conditions, it would return an empty array.
Under ​3.5, get_post_ancestors() returns an array of ancestors, as in 3.4, except, in the case where the $post passed in is NULL/FALSE/0/empty, then it now returns false.

This results in warning such as this: Warning: Invalid argument supplied for foreach() when the result of get_post_ancestors() was used directly in a loop,

Admitably, it's bad code which triggers this, calling get_post_ancestors() with the global $post object before it's set up in this case, but it's still a chance in behaviour which I felt needs documenting on trac. This is either a instant 'We should just return an array()' or 'wontfix: Plugins are doing it wrong and should fix their code' ticket.

This was found by debugging ​http://wordpress.org/support/topic/does-wordpress-35-still-support-is_tree?

[dd32]

Milestone set purely for "It's a 3.5.1 thing, or we don't do it at all"

[aaroncampbell]

I think returning array() here is a simple fix and I don't really see a downside.

[dannydehaan]

22882

[dannydehaan]

I've made a simple patch that returns an array when the variable $post isn't available.

[georgestephanis]

22882.diff +1

[nacin]

In 1177/tests:

Test that get_post_ancestors() returns an empty array when passed a value that evaluates to false. see #22882.

[nacin]

In 23212:

Always return arrays from get_post_ancestors(). Return an array when passed a value that evaluates to false.

props dannydehaan.
fixes #22882 for trunk.
Test: [1177/tests].

[nacin]

In 23213:

Always return arrays from get_post_ancestors(). Return an array when passed a value that evaluates to false.

Merges [23212] to the 3.5 branch.

props dannydehaan.
fixes #22882.

[SergeyBiryukov]

#23201 was marked as a duplicate.