wp_admin_notice(): pass `type` instead of `error/updated` via additional_classes

[hbhalodia]

While working on this #65690 and ​PR - , I got one feedback from the copilot ​here.

The feedback says that,

wp_admin_notice() supports a type argument (e.g. error), which produces the canonical notice notice-error class. Using additional_classes => array( 'error', ... ) is legacy-style and makes the class semantics less clear for new notices; prefer type => 'error' and keep hide-if-js as an additional class.

When I looked at the codebase, I found inconsistency accross the codebase, some use legacy-style and use type argument to construct the notice.

I would like to propose issue here and improve code quality, so that we can consistently use the new variation i.e., to add the type argument, instead of legacy-style i.e., to add classes to the admin notices.

Below is the detailed version created by AI, Claude Code, Opus 4.8 with details like where is inconsistency accross the codebase.

---

AI Summary

Since WordPress 6.4, wp_admin_notice() and wp_get_admin_notice() accept a type argument (error, success, warning, info) that outputs the standard notice notice-<type> classes.

Core is inconsistent in how it uses this. Some calls correctly pass type, while many others pass the legacy status class (error or updated) directly through additional_classes. Both render the same (core styles div.error / .notice-error and div.updated / .notice-success identically), but using type makes the intent explicit and keeps every call site consistent.

Correct usage — source:trunk/src/wp-login.php:

<?php
wp_admin_notice(
        $errors,
        array(
                'type'           => 'error',
                'id'             => 'login_error',
                'paragraph_wrap' => false,
        )
);

Inconsistent usage — source:trunk/src/wp-admin/upload.php:

<?php
wp_admin_notice(
        $js_required_message,
        array(
                'additional_classes' => array( 'error', 'hide-if-js' ),
        )
);

Proposed change

Convert the legacy status class to the type argument, keeping any other (non-status) classes in additional_classes:

• additional_classes => array( 'error' ) → type => 'error'
• additional_classes => array( 'updated' ) → type => 'success' (updated is the legacy green/success class)
• additional_classes => array( 'error', 'hidden' ) → type => 'error' + additional_classes => array( 'hidden' )

Output markup is equivalent, so this is low risk and can be split across multiple patches or in a single PR depends.

Line numbers are against trunk at the time of writing.

Group 1 — 'error' → type => 'error' (50)

File	Line(s)	Classes to keep
src/wp-admin/import.php	73	—
src/wp-admin/edit-form-advanced.php	469	hidden
src/wp-admin/theme-editor.php	316, 353	—
src/wp-admin/themes.php	304, 321, 350	—
src/wp-admin/update-core.php	1078, 1088	—
src/wp-admin/edit-comments.php	308	—
src/wp-admin/plugins.php	350, 364, 652, 704, 723	—
src/wp-admin/users.php	328, 720, 740, 760, 790, 816	—
src/wp-admin/upload.php	243	hide-if-js
src/wp-admin/user-new.php	407, 436	—
src/wp-admin/widgets-form.php	433	—
src/wp-admin/plugin-editor.php	37	—
src/wp-admin/theme-install.php	189	hide-if-js
src/wp-admin/user-edit.php	256	—
src/wp-admin/async-upload.php	137	error-div
src/wp-admin/nav-menus.php	316, 348, 391, 449, 478, 494	—
src/wp-admin/network/themes.php	142, 153	—
src/wp-admin/includes/file.php	2524	—
src/wp-admin/includes/class-wp-plugin-install-list-table.php	298	inline
src/wp-admin/includes/network.php	127, 168, 284, 435, 458	284: inline
src/wp-admin/includes/template.php	1023, 1447	1447: inline
src/wp-admin/includes/user.php	559	default-password-nag
src/wp-admin/includes/nav-menu.php	1464	—
src/wp-admin/includes/class-bulk-upgrader-skin.php	199	—
src/wp-includes/media-template.php	389	—

Group 2 — 'updated' → type => 'success' (39)

File	Line(s)	Classes to keep
src/wp-admin/edit-form-advanced.php	454	—
src/wp-admin/theme-editor.php	199	—
src/wp-admin/themes.php	266, 276, 285, 295, 312, 329, 338	—
src/wp-admin/options-general.php	284	inline
src/wp-admin/edit-comments.php	424	—
src/wp-admin/edit-link-form.php	100	—
src/wp-admin/plugins.php	661	—
src/wp-admin/nav-menus.php	288, 325, 361, 538, 704	—
src/wp-admin/plugin-editor.php	204	also is-dismissible → dismissible => true
src/wp-admin/user-new.php	419	—
src/wp-admin/widgets-form.php	423	—
src/wp-admin/users.php	656, 682, 700, 710, 729, 749, 769, 780, 798	780, 798: fade
src/wp-admin/upload.php	229, 446	—
src/wp-admin/user-edit.php	233, 599	599: inline
src/wp-admin/link-manager.php	129	—
src/wp-admin/edit.php	476	—
src/wp-admin/includes/nav-menu.php	1519	—
src/wp-admin/includes/class-custom-background.php	271	—
src/wp-admin/includes/class-custom-image-header.php	540	—

Group 3 — Dynamic status class (2)

These build the class from a variable and need a conditional type instead:

File	Line	Detail
src/wp-admin/edit-tags.php	360	$class = isset( $_REQUEST['error'] ) ? 'error' : 'updated'; — set type to 'error' / 'success'
src/wp-admin/includes/network.php	234	$message_class is '', 'updated', or 'error' (set at lines 201–213) — map to type; keep inline

Not included (correct as-is)

These additional_classes values are behavioural/modifier classes with no type equivalent and should stay: notice-alt, inline, hidden, fade, hide-if-js / hide-if-no-js, below-h2, update-message, update-nag (a distinct legacy style, not one of the four types), the login-specific message / reset-pass / register, and notice-missing-attachment. Substrings such as error-div, community-events-errors and policy-text-updated are unrelated class names, not status types.

Thanks,

Trac ticket: https://core.trac.wordpress.org/ticket/65703

## Use of AI Tools

• Yes
• Claude Code, Opus 4.8
• Used for drafting the issue description and also for performing the code updates.

[joedolson]

To provide a little history on this, when we implemented wp_admin_notice() across core, we made the decision not to update all the legacy classes to the modern classes, so that we reduced churn on the output in that single release. It should be safe; it's unlikely that there are many plugins out there depending on a given notice using the .updated class at this point.