fix: Invalidate editor cache when plugins feature flag changes #25170

dcalhoun · 2026-01-26T22:54:25Z

Description

Fix CMM-1174.

This PR fixes an issue where block editor plugins fail to load on fresh app install when the gutenberg_kit_plugins feature flag is toggled after the editor dependencies have been prefetched.

Root cause: When the app launches, EditorDependencyManager prefetches editor dependencies including asset bundles. If the plugins flag is disabled at that time, an empty asset bundle is cached. When the user later enables the flag and opens the editor, the stale cached empty bundle is used, causing the "Loading plugins failed" notice.

Solution:

Track the newGutenbergPlugins flag value when caching dependencies
On each prefetch call, check if the flag value has changed since the last cache
If changed, invalidate all cached entries and re-prefetch with the current flag state

Additionally, this PR consolidates editor warmup logic:

Moved warmUpEditorIfNeeded from MySiteViewController to BlogDashboardViewModel
Removed redundant prefetch call from PostListViewController
Ensured prefetchDependencies is always called (not guarded by blog change) so flag changes can be detected

Testing instructions

Fresh install the app
Enable the Experimental Block Editor feature flag
Ensure gutenberg_kit_plugins feature flag is disabled via the debug menu
Navigate to My Site (this triggers the prefetch with empty bundle)
Enable the gutenberg_kit_plugins feature flag via debug menu
Navigate away from and back to My Site (this triggers the prefetch with a populated bundle)
Open the block editor
Expected: Plugins load successfully (no "Loading plugins failed" notice)
Previous behavior: "Loading plugins failed" notice appeared

dangermattic · 2026-01-26T22:55:09Z

	1 Message
📖	This PR is still a Draft: some checks will be skipped.

Generated by 🚫 Danger

The preloading is unnecessary and also lead to confusing cache states. The invalid cache states were addressed in a separate commit.

Warming and preloading the editor in both the MySiteViewController and BlogDashboardViewModel is redundant. The former embeds the latter.

This is arguably duplicative of the preloading within BlogDashboardViewModel.

When preloading GutenbergKit while plugins are disabled, an empty editor bundle is cached. The editor continues using this this bundle until it expires or the pull-to-refresh gesture is performed on the My Site view. If the plugins feature is later enabled, the empty bundle is used and leads to confusing plugin loading failed warnings. To avoid unexpectedly empty bundles, we invalidate all bundles when the plugins feature flag changes.

GutenbergKit's dependency prefetch manages its own cache and avoids re-fetching dependencies.

sonarqubecloud · 2026-01-26T23:11:28Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

wpmobilebot · 2026-01-26T23:28:46Z

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	`30614`
	Version	`PR #25170`
	Bundle ID	`org.wordpress.alpha`
	Commit	`17a8262`
	Installation URL	1o8laergk0gu8

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

wpmobilebot · 2026-01-26T23:28:51Z

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	`30614`
	Version	`PR #25170`
	Bundle ID	`com.jetpack.alpha`
	Commit	`17a8262`
	Installation URL	7heudll6iv6j0

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

wpmobilebot · 2026-01-26T23:51:27Z

🤖 Build Failure Analysis

This build has failures. Claude has analyzed them - check the build annotations for details.

dcalhoun · 2026-01-26T23:00:28Z

WordPress/Classes/Utility/Editor/EditorDependencyManager.swift

+        if let lastFlagValue, lastFlagValue != currentPluginsFlagValue {
+            // Flag changed - invalidate all cached entries
+            DDLogInfo("EditorDependencyManager: Plugins flag changed (\(lastFlagValue) -> \(currentPluginsFlagValue)), invalidating all cached dependencies")
+            cache.removeAll()
+            prefetchTasks.removeAll()
+        }


This is the fix for the unexpected "Plugin loading failed, using default editor configuration" warning.

GutenbergKit's preloading logic returns an empty bundle if plugins is disabled. The app preloaded and cached an empty asset bundle, then continued utilizing it even after the plugins feature was enabled. Invalidating the cache ensure GutenbergKit preloads an appropriate bundle.

dcalhoun · 2026-01-26T23:01:00Z

WordPress/Classes/ViewRelated/Blog/Blog Dashboard/ViewModel/BlogDashboardViewModel.swift


    func viewWillAppear() {
-        EditorDependencyManager.shared.prefetchDependencies(for: self.blog)
+        warmUpEditorIfNeeded(for: self.blog)


Introduced to avoid unnecessary preloading if GutenbergKit is disabled.

dcalhoun · 2026-01-26T23:01:57Z

WordPress/Classes/ViewRelated/Blog/My Site/MySiteViewController.swift

-        if RemoteFeatureFlag.newGutenberg.enabled() {
-            warmUpEditorIfNeeded(for: blog)
-        }


Consolidated to BlogDashboardViewModel as it appears to be duplication to have this in both places.

dcalhoun · 2026-01-26T23:03:03Z

WordPress/Classes/ViewRelated/Post/Controllers/PostListViewController.swift

-
-        if let blog = self.blog {
-            EditorDependencyManager.shared.prefetchDependencies(for: blog)
-        }


Removed as this feels duplicative of BlogDashboardViewModel. It's difficult (impossible?) to navigate to the post list without first navigating to My Site.

dcalhoun added Posting/Editing Gutenberg Editing and display of Gutenberg blocks. Bug labels Jan 26, 2026

dcalhoun added 6 commits January 26, 2026 18:07

perf: Disable GutenbergKit preloading if GutenbergKit is disabled

da84446

The preloading is unnecessary and also lead to confusing cache states. The invalid cache states were addressed in a separate commit.

perf: Consolidate duplicative editor warmups

4991171

Warming and preloading the editor in both the MySiteViewController and BlogDashboardViewModel is redundant. The former embeds the latter.

perf: Remove PostListViewController editor preloading

bda16ec

This is arguably duplicative of the preloading within BlogDashboardViewModel.

fix: Always prefetch editor dependencies

a98a5c5

GutenbergKit's dependency prefetch manages its own cache and avoids re-fetching dependencies.

build: Update GutenbergKit version

17a8262

dcalhoun force-pushed the fix/mitigate-empty-editor-asset-bundles-errors branch from 9188217 to 17a8262 Compare January 26, 2026 23:08

dcalhoun changed the base branch from trunk to release/26.6 January 26, 2026 23:08

dcalhoun added this to the 26.6 ❄️ milestone Jan 26, 2026

dcalhoun commented Jan 26, 2026

View reviewed changes

dcalhoun marked this pull request as ready for review January 26, 2026 23:54

dcalhoun requested a review from jkmassel January 26, 2026 23:55

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fix: Invalidate editor cache when plugins feature flag changes #25170

fix: Invalidate editor cache when plugins feature flag changes #25170

dcalhoun commented Jan 26, 2026 •

edited

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Description

Testing instructions

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Quality Gate passed

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dcalhoun commented Jan 26, 2026 •

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