Guidelines: Drop default_term from wp_guideline_type taxonomy by gziolo · Pull Request #77592 · WordPress/gutenberg

gziolo · 2026-04-23T07:38:30Z

What

Stop passing default_term when registering the wp_guideline_type taxonomy. Assign the artifact fallback from a save_post_wp_guideline hook instead, and only when the saved post has no type term yet.

Why

Registering the taxonomy with default_term routes through core paths that trigger cross-site clean_term_cache work. On multisite installations with a large number of sites (reported on WordPress.com after v23.0.0), this caused significant load even for sites with zero guidelines posts. The default_term registration argument also has limited precedent in core and is not well-tested under caching/invalidation scenarios.

How

Remove the default_term argument from register_taxonomy().
Add Gutenberg_Guidelines_Post_Type::ensure_default_type_term() that runs on save_post_wp_guideline. Because that action fires after wp_insert_post() processes tax_input, any explicit term is already attached when the callback runs. The callback queries attached terms and only assigns artifact when none are present.
The REST controller's singleton creation already sets content via tax_input, so that path is a no-op for this new hook.

Behavior

REST singleton create → content attached → hook is a no-op.
Manual /wp-admin create with a type chosen → user term attached → hook is a no-op.
Manual create with no type chosen → artifact assigned.
Subsequent updates → post already has a term → hook is a no-op.

Test plan

Existing Gutenberg_Guidelines_REST_Controller_Test suite passes (31 tests).
Verify on a fresh install that no guidelines posts exist and no taxonomy-related DB writes occur on init.
Create a wp_guideline post via wp-admin without picking a type → confirm it gets the artifact term.
Create a wp_guideline post via wp-admin with a type picked → confirm the picked term is preserved.
Exercise the REST create endpoint → confirm the content term is assigned.

🤖 Generated with Claude Code

Registering the taxonomy with default_term triggers cross-site clean_term_cache work, which caused major load on multisite installs with many sites even when no guidelines existed. Replace it with a save_post_wp_guideline callback that assigns the artifact fallback only when the post has no type term yet. The REST controller's singleton path already sets content explicitly via tax_input, so that flow is unaffected. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

github-actions · 2026-04-23T07:38:40Z

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Co-authored-by: gziolo <gziolo@git.wordpress.org>
Co-authored-by: tyxla <tyxla@git.wordpress.org>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

Covers: - Regression guard that the taxonomy is registered without default_term. - The save_post fallback assigns artifact only when the post has no type. - An explicit type passed via tax_input is preserved, not overwritten. - Updates to an existing post do not reset the term. - The hook is scoped to wp_guideline and leaves other post types alone. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Move the save_post_wp_guideline registration inside the register() method so it lives behind the same post_type_exists() guard as the CPT itself. If WordPress core ever ships the guidelines CPT and its own fallback hook, Gutenberg will skip both and avoid registering a duplicate callback. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tyxla

This looks mostly good, but I have another potential concern about performance.

github-actions · 2026-04-23T10:19:36Z

Flaky tests detected in de55e44.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/24876505973
📝 Reported issues:

[Flaky Test] post title and content are editable and blocks can be inserted #76524 in /test/e2e/specs/editor/various/post-content-focus-mode.spec.js

wp_get_object_terms() queries the database directly on every call. get_the_terms() uses the object term cache populated by update_object_term_cache(), which keeps repeated reads cheap within the same request. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tyxla

This is looking good and works well. 👍

I've added a few suggestions to address before landing it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

luisherranz · 2026-04-24T11:31:00Z

I just cherry-picked this PR to the release/23.0 branch to get it included in the next release: 89ce73e

* Guidelines: Drop default_term from wp_guideline_type registration Registering the taxonomy with default_term triggers cross-site clean_term_cache work, which caused major load on multisite installs with many sites even when no guidelines existed. Replace it with a save_post_wp_guideline callback that assigns the artifact fallback only when the post has no type term yet. The REST controller's singleton path already sets content explicitly via tax_input, so that flow is unaffected. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * Guidelines: Add unit tests for taxonomy default-term behavior Covers: - Regression guard that the taxonomy is registered without default_term. - The save_post fallback assigns artifact only when the post has no type. - An explicit type passed via tax_input is preserved, not overwritten. - Updates to an existing post do not reset the term. - The hook is scoped to wp_guideline and leaves other post types alone. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * Guidelines: Scope the save_post hook to Gutenberg's own registration Move the save_post_wp_guideline registration inside the register() method so it lives behind the same post_type_exists() guard as the CPT itself. If WordPress core ever ships the guidelines CPT and its own fallback hook, Gutenberg will skip both and avoid registering a duplicate callback. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * Guidelines: Use get_the_terms so the check hits the object term cache wp_get_object_terms() queries the database directly on every call. get_the_terms() uses the object term cache populated by update_object_term_cache(), which keeps repeated reads cheap within the same request. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * Guidelines: Drop redundant autosave check and cover revisions in tests Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Co-authored-by: gziolo <gziolo@git.wordpress.org> Co-authored-by: tyxla <tyxla@git.wordpress.org>

* Guidelines: Drop default_term from wp_guideline_type registration Registering the taxonomy with default_term triggers cross-site clean_term_cache work, which caused major load on multisite installs with many sites even when no guidelines existed. Replace it with a save_post_wp_guideline callback that assigns the artifact fallback only when the post has no type term yet. The REST controller's singleton path already sets content explicitly via tax_input, so that flow is unaffected. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * Guidelines: Add unit tests for taxonomy default-term behavior Covers: - Regression guard that the taxonomy is registered without default_term. - The save_post fallback assigns artifact only when the post has no type. - An explicit type passed via tax_input is preserved, not overwritten. - Updates to an existing post do not reset the term. - The hook is scoped to wp_guideline and leaves other post types alone. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * Guidelines: Scope the save_post hook to Gutenberg's own registration Move the save_post_wp_guideline registration inside the register() method so it lives behind the same post_type_exists() guard as the CPT itself. If WordPress core ever ships the guidelines CPT and its own fallback hook, Gutenberg will skip both and avoid registering a duplicate callback. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * Guidelines: Use get_the_terms so the check hits the object term cache wp_get_object_terms() queries the database directly on every call. get_the_terms() uses the object term cache populated by update_object_term_cache(), which keeps repeated reads cheap within the same request. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> * Guidelines: Drop redundant autosave check and cover revisions in tests Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Co-authored-by: gziolo <gziolo@git.wordpress.org> Co-authored-by: tyxla <tyxla@git.wordpress.org> Co-authored-by: simison <87168+simison@users.noreply.github.com>

gziolo requested a review from spacedmonkey as a code owner April 23, 2026 07:38

gziolo and others added 2 commits April 23, 2026 09:47

gziolo requested a review from tyxla April 23, 2026 07:52

gziolo self-assigned this Apr 23, 2026

gziolo added [Type] Bug An existing feature does not function as intended [Feature] Guidelines An experimental feature for adding site-wide editorial rules. Backport to Gutenberg Minor Release Pull request that needs to be backported to a Gutenberg minor release labels Apr 23, 2026

tyxla reviewed Apr 23, 2026

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tyxla approved these changes Apr 23, 2026

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Comment thread lib/experimental/guidelines/class-gutenberg-guidelines-post-type.php Outdated

Comment thread phpunit/experimental/guidelines/class-gutenberg-guidelines-post-type-test.php Outdated

Comment thread lib/experimental/guidelines/class-gutenberg-guidelines-post-type.php Outdated

Guidelines: Drop redundant autosave check and cover revisions in tests

de55e44

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

gziolo enabled auto-merge (squash) April 24, 2026 06:54

gziolo merged commit 1789697 into trunk Apr 24, 2026
40 of 42 checks passed

gziolo deleted the fix/guidelines-taxonomy-default-term branch April 24, 2026 07:37

github-actions Bot added this to the Gutenberg 23.1 milestone Apr 24, 2026

gziolo mentioned this pull request Apr 24, 2026

Guidelines: Extract initial public API methods #77643

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luisherranz modified the milestones: Gutenberg 23.1, Gutenberg 23.0 Apr 24, 2026

luisherranz removed the Backport to Gutenberg Minor Release Pull request that needs to be backported to a Gutenberg minor release label Apr 24, 2026

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Guidelines: Drop default_term from wp_guideline_type taxonomy#77592

Guidelines: Drop default_term from wp_guideline_type taxonomy#77592
gziolo merged 5 commits intotrunkfrom
fix/guidelines-taxonomy-default-term

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gziolo commented Apr 23, 2026

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