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Ignore:
Timestamp:
10/11/2016 01:55:58 AM (8 years ago)
Author:
boonebgorges
Message:

Taxonomy: Better error handling when fetching object terms from cache.

Since [37573], get_object_term_cache() has expected term IDs to be
stored in the taxonomy relationship cache. The function would then
reach directly into the 'terms' cache to fetch the data corresponding
to a given term, before returning a WP_Term object. This caused
problems when, for one reason or another, term data was cached
inconsistently:

  • If the 'terms' cache is empty for a given term ID, despite the earlier call to _prime_term_caches(), get_term() would return an error object.
  • If the array of cached term IDs contains an invalid ID, get_term() would return an error object.

We avoid these errors by no longer touching the 'terms' cache directly,
but running term IDs through get_term() and allowing that function to
reference the cache (and database, as needed). If get_term() returns
an error object for any of the cached term IDs, get_object_term_cache()
will return that error object alone. This change ensures that upstream
functions, like get_the_terms(), return WP_Error objects in a
predictable fashion.

Props dd32, michalzuber.
Fixes #37291.

File:
1 edited

Legend:

Unmodified
Added
Removed
  • trunk/tests/phpunit/tests/term/cache.php

    r38677 r38776  
    391391        $this->assertEquals( $num_queries, $wpdb->num_queries );
    392392    }
     393
     394    /**
     395     * @ticket 37291
     396     */
     397    public function test_get_object_term_cache_should_return_error_if_any_term_is_an_error() {
     398        register_taxonomy( 'wptests_tax', 'post' );
     399
     400        $t = self::factory()->term->create( array( 'taxonomy' => 'wptests_tax' ) );
     401        $p = self::factory()->post->create();
     402        wp_set_object_terms( $p, $t, 'wptests_tax' );
     403
     404        // Prime cache.
     405        $terms = get_the_terms( $p, 'wptests_tax' );
     406        $this->assertEqualSets( array( $t ), wp_list_pluck( $terms, 'term_id' ) );
     407
     408        /*
     409         * Modify cached array to insert an empty term ID,
     410         * which will trigger an error in get_term().
     411         */
     412        $cached_ids = wp_cache_get( $p, 'wptests_tax_relationships' );
     413        $cached_ids[] = 0;
     414        wp_cache_set( $p, $cached_ids, 'wptests_tax_relationships' );
     415
     416        $terms = get_the_terms( $p, 'wptests_tax' );
     417        $this->assertWPError( $terms );
     418    }
    393419}
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