_deep_replace can cause infinite loop

[mdawaffe]

Calling _deep_replace( $search, $subject ) on an array $subject can cause an infinite loop since strpos( array(), 'foo' ) will return NULL.

Patch attached.

[nacin]

Sounds like that's incorrect use as it only wants a string, but that said, seems like a fine defensive check to me.

[nacin]

Wrong ticket referenced:

(In [13983]) Cast subject of _deep_replace() to string to prevent an infinite loop. props mdawaffe, fixes #12386

[mdawaffe]

Replying to nacin:

Sounds like that's incorrect use as it only wants a string, but that said, seems like a fine defensive check to me.

It is an incorrect use. I came across the problem when I accidentally did esc_url( get_post_meta( ... ) ) (since get_post_meta returns an array by default).