[wp-trac] [WordPress Trac] #31665: Duplicate slugs in DB, created for hierarchical terms with long, non-latin names, when the default slug already exists

[WordPress Trac]

#31665: Duplicate slugs in DB, created for hierarchical terms with long, non-latin
names, when the default slug already exists
--------------------------+-----------------------------
 Reporter:  nevma         |      Owner:
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Taxonomy      |    Version:  4.1.1
 Severity:  normal        |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 When WP automatically generates a slug for a child term, and if the
 produced slug (which is normally generated just from the term's name)
 already exists in that taxonomy, it forms a slug by concatenating all the
 parent terms' slugs hierarchically

 For example, in a term structure like:
 Parent
 -Child

 If a term with the name "Grandchild" is to be inserted under "Child",
 normally it would get the slug "grandchild". However if that slug already
 exists in the taxonomy, WP generates the slug "parent-child-grandchild".

 When the slugs have long, non-latin names, they are stored urlencoded in
 wp_terms, and the stored string's length can easily overflow the field's
 size ( varchar(200) ). Any terms created under that condition end up
 having the same slug stored in the DB (the produced urlencoded one,
 truncated to 200 chars).

 To reproduce the issue:

 Create a term (e.g. category) with this name (without the quotes): "Ένα
 δύο τρία τέσσερα πέντε"
 Create another term with the same name, defining the first term as its
 parent.
 Create a third term with the same name, defining the second term as its
 parent.

 The second and third terms end up having duplicate slugs in the DB, a
 situation which is normally an error.

 This issue is also not detected if the same procedure is repeated using
 wp_insert_term(). Normally an attempt to insert a duplicate slug to the
 same taxonomy would raise a "duplicate_term_slug" WP_Error, which is not
 the case.

--
Ticket URL: <https://core.trac.wordpress.org/ticket/31665>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform