Delete legacy mu-plugin files that lived in site filesystem#2655
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Delete legacy mu-plugin files that lived in site filesystem#2655
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Older Studio versions wrote mu-plugin PHP files directly into wp-content/mu-plugins/. Newer versions inject them at runtime via the PHP WASM virtual filesystem. Having both causes "Cannot redeclare" PHP fatal errors. This adds a cleanup step that removes known legacy files before starting the server or running WP-CLI commands. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
sejas
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sejas
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…cleanup-legacy-mu-plugins
epeicher
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Feb 25, 2026
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epeicher
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Thanks @sejas for solving this, and thanks for the detailed testing instructions! I have tested it, and I confirm that the deprecated files are deleted after starting Studio as expected. Changes also LGTM! 
| Before starting Studio | After starting Studio |
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Related issues
Proposed Changes
Sites created with older Studio versions (e.g June 2024) have physical
0-*.phpmu-plugin files inwp-content/mu-plugins/. Newer Studio versions inject the same mu-plugins at runtime via the PHP WASM virtual filesystem (/internal/studio/mu-plugins/). When both copies exist, PHP encounters fatal errors likeCannot redeclare check_current_theme_availability().This PR adds a
cleanupLegacyMuPlugins()function that removes known legacy Studio mu-plugin files from the site'swp-content/mu-plugins/directory before starting the WordPress server or running WP-CLI commands.Changes:
cleanupLegacyMuPlugins(sitePath)intools/common/lib/mu-plugins.tswith an allowlist of 22 known legacy filenames (current + retired)wordpress-server-child.tsbefore building CLI argsrun-wp-cli-command.tsbefore mounting mu-pluginsTesting Instructions
wp-content/mu-plugins/directory:wp-content/mu-plugins/rayden-muplugins-remove.mp4
Pre-merge Checklist