[wp-trac] [WordPress Trac] #34533: Term splitting in `get_term()` can have unexpected effects

[WordPress Trac]

#34533: Term splitting in `get_term()` can have unexpected effects
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 Reporter:  dlh           |       Owner:
     Type:  defect (bug)  |      Status:  new
 Priority:  high          |   Milestone:  4.4
Component:  Taxonomy      |     Version:  trunk
 Severity:  normal        |  Resolution:
 Keywords:  has-patch     |     Focuses:
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Comment (by boonebgorges):

 I realized after writing the first patch that there could be further cache
 confusion when there are shared terms. Calling `get_term( $term_id, 'foo'
 )` will populate the cache with the `foo` term; if it's shared with
 taxonomy `bar`, then `get_term( $term_id, 'bar' )` will incorrectly fetch
 the `foo` term from the cache. [attachment:34533.2.diff] fixes this.

 There is still the possibility for cache entanglement. Specifically, if
 you don't specify a `$taxonomy` in `get_term()`, then you're going to get
 whatever's in the cache, and if your `$term_id` is shared between
 taxonomies, what's in the cache may not be what you wanted. There's not
 really anything we can do about this, and I think it's reasonable to say
 that if you want support for the new `get_term( $term_id )` syntax, that
 you need to have run the term-splitting routine in order to guarantee
 coherent caching. (The only other alternative, without ripping the whole
 thing out, is to skip single-term caching when
 'finished_splitting_shared_terms' is not true. Pretty ugly.)

 Cache confusion for single-term caches would be much harder to deal with
 if we were using those caches in places like `get_terms()`. Luckily, we
 are not doing this at the moment, but it's going to be an unpleasant
 hurdle when we finally do.

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Ticket URL: <https://core.trac.wordpress.org/ticket/34533#comment:2>
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