View config: reject shape-mismatched merges, define empty-array semantics, strip nulls from appended members by jorgefilipecosta · Pull Request #12644 · WordPress/wordpress-develop

jorgefilipecosta · 2026-07-22T13:27:54Z

What?

Follow up to #12638. Gutenberg PR: WordPress/gutenberg#80571.

Fixes three silent data-loss defects in WP_View_Config_Data's merge engine:

An associative patch value over a list (or a non-empty list over an associative value) discarded the whole current value. It is now rejected with _doing_it_wrong() and the current value is kept.
An empty array under merge() wiped associative values but no-oped on lists. It is now a no-op for both shapes — clear a list with replace() and an empty list, reset a key with null.
A list member appended by merge() kept nested nulls that every other write path drops. Appended members now go through strip_nulls().

How?

merge_properties(): a patch value only merges into a current value of the same shape. Non-empty mismatches warn and keep the current value; an empty array merges nothing. Empty arrays stay exempt from the guards, so an associative patch still creates new nested maps.
merge_list_by_identity(): appended members go through strip_nulls().
Docblocks document the rule.

Testing

Verify unit tests are passing:

npm run test:php -- --filter Tests_View_Config_Data

One new test per fix; the inline PR comments show each assertion's result without the fix.

AI usage disclosure: issues found via AI-assisted code review; fix, tests, and description drafted with AI assistance (Claude Code) and reviewed by me.

Trac ticket: https://core.trac.wordpress.org/ticket/65577

merge_properties() classified patch values by shape but let a mismatch fall through: an associative patch value landing on a list (or a list landing on an associative value) silently discarded the current value before merging into nothing, and an empty array — classified as a list — wiped associative values while no-oping on lists. An unmatched list member was also appended verbatim, storing nested nulls that every other write path consumes. A non-empty shape mismatch is now reported with _doing_it_wrong() and leaves the current value unchanged, an empty array under merge() is a documented no-op (clearing stays with replace() and null), and appended list members have their nulls stripped like every other path with no existing leaf to delete. See #65577.

github-actions · 2026-07-22T13:28:49Z

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props jorgefilipecosta, mukesh27, oandregal.

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Copilot

Pull request overview

This pull request hardens WP_View_Config_Data’s patch merge behavior to prevent silent configuration loss and schema-violating output when merge patches don’t match the current value’s shape, aligning server behavior with the documented patch contract and the referenced Gutenberg fix.

Changes:

Reject non-empty shape mismatches during merge() (associative-over-list and list-over-associative) via _doing_it_wrong() while leaving the current value unchanged.
Treat empty arrays in merge() patches as a documented no-op for both list and associative shapes.
Strip nested null values from newly appended list members during identity-based list merging, matching other write paths.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
`src/wp-includes/class-wp-view-config-data.php`	Updates merge internals to guard against shape mismatches, define empty-array merge semantics, and strip nulls from appended list items.
`tests/phpunit/tests/view-config-data.php`	Adds focused PHPUnit coverage for the three fixed defects (plus the mirror mismatch guard).

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jorgefilipecosta

Pre-fix test results: each new test was run against trunk's class (source change reverted, tests kept) to confirm it fails without this PR. Per-assertion output inline.

jorgefilipecosta · 2026-07-22T13:36:48Z

+			1
+		);
+
+		$this->assertSame( $before, self::read_config( $data ) );


Result of this assertion without the fix:

array( 'view_list' => array( 'published' => array( 'title' => 'Live' ), ), )

The default all view is gone, view_list became a slug-keyed map instead of a list, with no notice.

jorgefilipecosta · 2026-07-22T13:36:48Z

+			1
+		);
+
+		$this->assertSame( $before, self::read_config( $data ) );


Result of this assertion without the fix:

array( 'default_view' => array( 'sort' => array( 'title', 'asc' ), ), )

The sort map (field/direction) was replaced by the bare list, with no notice.

jorgefilipecosta · 2026-07-22T13:36:48Z

+			1
+		);
+
+		$this->assertSame( $before, self::read_config( $data ) );


Result of this assertion without the fix:

array( 'default_view' => array( 'filters' => array( array( 'field' => 'author', 'operator' => 'isAny', ), ), 'sort' => array(), ), )

The same empty-array patch left filters untouched but emptied sort: one input, two different outcomes depending on the current shape.

jorgefilipecosta · 2026-07-22T13:36:48Z

+			1
+		);
+
+		$this->assertSame(


Result of this assertion without the fix:

array( 'view_list' => array( array( 'slug' => 'all', 'title' => 'All items', ), array( 'slug' => 'mine', 'view' => array( 'filters' => null ), ), ), )

The appended member kept the literal 'filters' => null instead of dropping it the way every other write path does.

github-actions · 2026-07-22T13:39:51Z

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Test this pull request with WordPress Playground.

The $method parameter threaded through merge_properties() and merge_list_by_identity() existed only to name the public method in the _doing_it_wrong() notice. Report via __METHOD__ with a single shape-agnostic message instead, keeping the notice actionable without the extra plumbing. See #65577.

Copilot

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

mukeshpanchal27 · 2026-07-22T16:41:19Z

+	 *
+	 * @covers ::merge


Suggested change

*

* @covers ::merge

* @ticket 65577

*

* @covers ::merge

Add ticket annotation in all new tests

A non-empty list patch value applied with replace() bypassed the new shape guard and silently swapped out an associative current value, while the associative-over-list direction was already rejected. The guard now runs before the replace() early return, covering both modes; an empty array stays exempt so replace() with an empty list still clears a list.

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Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

src/wp-includes/class-wp-view-config-data.php:501

The merge_properties() docblock says an empty array “merges nothing, so it is a no-op”, but merge_properties() is also used by replace() where an empty list can intentionally clear a list (because $replace_lists swaps lists wholesale). Consider clarifying this sentence to avoid implying the no-op rule applies to replace() as well.

	 * patch cannot silently destroy configuration. An empty array is
	 * shape-ambiguous and merges nothing, so it is a no-op: clearing a list is
	 * spelled replace() with an empty list, and resetting a key is spelled
	 * `null`.

github-actions · 2026-07-23T16:26:02Z

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 62833
GitHub commit: b0e62d8

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.

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jorgefilipecosta changed the title ~~REST API: Fix silent data loss in view configuration merges~~ View config: reject shape-mismatched merges, define empty-array semantics, strip nulls from appended members Jul 22, 2026

This was referenced Jul 22, 2026

View config: reject shape-mismatched merges, define empty-array semantics, strip nulls from appended members WordPress/gutenberg#80571

Merged

Sync view configuration API updates from Gutenberg #12638

Closed

jorgefilipecosta added the bug label Jul 22, 2026

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Comment thread src/wp-includes/class-wp-view-config-data.php

mukeshpanchal27 reviewed Jul 22, 2026

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oandregal approved these changes Jul 23, 2026

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jorgefilipecosta added 2 commits July 23, 2026 15:32

View config: Add ticket annotations to the new merge tests.

b75fdfa

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github-actions Bot mentioned this pull request Jul 23, 2026

PHP backports for WP 7.1 WordPress/gutenberg#79304

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