wp_check_term_hierarchy_for_loops( int $parent_term, int $term_id, string $taxonomy ): int
- Since
- 3.1.0
- Source
wp-includes/taxonomy.php:5063
Description
Prevents loops from forming and breaks those that it finds.
Attached to the 'wp_update_term_parent' filter.
Compatibility
- WordPress
- since 3.1.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$parent_termintterm_idof the parent for the term we're checking.$term_idint- The term we're checking.
$taxonomystring- The taxonomy of the term we're checking.
Return value
int- The new parent for the term.
Performance profile
How much work a call to wp_check_term_hierarchy_for_loops() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Heavy
- Scaling
- Scales with input
- Instructions
- 5–24
- Plugin surface
- None
- Called by
- 0
Reaches the database via get_term().
The body loops, so the work grows with what you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 34.
Nothing here hands control to plugin code.
Nothing in core calls this; the cost is only what you spend yourself.
What it touches
- querycontent query
get_term()one call below wp_check_term_hierarchy_for_loops() - hookthird-party callbacks
apply_filters()one call below wp_check_term_hierarchy_for_loops()
Further down the call graph this can also reach option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 2 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_check_term_hierarchy_for_loops() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 5–18 | none |
$parent_term !== false && !isset($loop[$term_id]) | 23–24 | array_keys() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 34 instructions, 5–24 executed per call, 6 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Uses · 2
- wp_find_hierarchy_loop()Finds hierarchy loops using a callback function that maps object IDs to parent IDs.
- wp_update_term()Updates term based on arguments provided.
Source code
function wp_check_term_hierarchy_for_loops( $parent_term, $term_id, $taxonomy ) { // Nothing fancy here - bail. if ( ! $parent_term ) { return 0; } // Can't be its own parent. if ( $parent_term === $term_id ) { return 0; } // Now look for larger loops. $loop = wp_find_hierarchy_loop( 'wp_get_term_taxonomy_parent_id', $term_id, $parent_term, array( $taxonomy ) ); if ( ! $loop ) { return $parent_term; // No loop. } // Setting $parent_term to the given value causes a loop. if ( isset( $loop[ $term_id ] ) ) { return 0; } // There's a loop, but it doesn't contain $term_id. Break the loop. foreach ( array_keys( $loop ) as $loop_member ) { wp_update_term( $loop_member, $taxonomy, array( 'parent' => 0 ) ); } return $parent_term;}Changelog
Introduced in 3.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 6.9.7 tag, from
src/wp-includes/taxonomy.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.