Fix child theme activation failure on subsequent runs with different slug and name

[Copilot]

Fix child theme activation failure on subsequent runs with different slug and name

Problem

When running wp scaffold child-theme with --activate flag where theme_slug and theme_name are different, the activation works on the first run but fails on the second run after deleting and recreating the theme.

Test failure: The theme activate command was reporting "The theme directory 'first-run' does not exist" even after clearing WordPress transients, object cache, and PHP filesystem cache.

Root Cause

WordPress caches theme information in multiple layers, including individual WP_Theme object caches that persist error states. When a theme is deleted, WordPress creates a WP_Theme object with an error state ("The theme directory ... does not exist") that gets cached. When the theme is recreated, this cached error object prevents activation even after clearing global caches.

The caching layers involved:

1. PHP filesystem cache (stat cache) - cleared with clearstatcache() ✓
2. Site transient theme_roots - cleared with delete_site_transient() ✓
3. Object cache themes in the themes group - cleared with wp_cache_delete() ✓
4. Individual WP_Theme object caches (theme-{hash}, screenshot-{hash}, headers-{hash}, page_templates-{hash}) - was NOT being cleared ✗
5. Theme directory cache via search_theme_directories() - rebuilt ✓

Solution

Updated refresh_theme_cache() method to clear all cache layers including individual WP_Theme object caches. The cache keys are calculated using md5($theme_root . '/' . $theme_slug) and cleared for all four cache types: theme, screenshot, headers, and page_templates. This follows the same pattern used in WP-CLI's Theme_Command which includes the comment "Clear cache so WP_Theme doesn't create a 'missing theme' object."

Changes

• src/Scaffold_Command.php:
  • Added clearstatcache() to clear PHP's filesystem stat cache
  • Added code to clear individual WP_Theme object caches for the specific theme
  • Updated refresh_theme_cache() to accept $theme_slug parameter
  • Updated method calls to pass the theme slug
• features/scaffold.feature: Test scenario validates the fix by creating, deleting, and recreating a child theme with activation

Testing

• All lint, code style, and static analysis checks pass
• Code properly clears all WordPress theme caches including PHP filesystem cache and individual WP_Theme object caches
• CI will run full Behat test suite to validate the fix works

Original prompt

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This section details on the original issue you should resolve

<issue_title>--activate fails after running second time if theme_slug and theme_name are different.</issue_title>
<issue_description>## Bug Report

• Yes, I reviewed the contribution guidelines.
• Yes, more specifically, I reviewed the guidelines on how to write clear bug reports.

Describe the current, buggy behavior
Run the following commands in order:

$ vendor/bin/wp scaffold child-theme first_run --parent_theme=twentytwenty --theme_name="first_run_name" --activate --path=../../
Success: Created '/srv/www/wordpress-one/public_html/wp-cli-dev/scaffold-command/../../wp-content/themes/first_run'.
Success: Switched to 'first_run_name' theme.

$ rm -rf ../../wp-content/themes/first_run/
$ wp theme activate twentytwenty

$ vendor/bin/wp scaffold child-theme first_run --parent_theme=twentytwenty --theme_name="first_run_name" --activate --path=../../
Success: Created '/srv/www/wordpress-one/public_html/wp-cli-dev/scaffold-command/../../wp-content/themes/first_run'.
Error: The theme directory "first_run" does not exist.

During the second run the command incorrectly looks for first_run instead of first_run_name to switch to.

Describe what you would expect as the correct outcome

I would expect the server to switch to the correct theme.

Let us know what environment you are running this on

$ vendor/bin/wp cli info
OS:	Linux 5.4.0-91-generic wp-cli/scaffold-command#102-Ubuntu SMP Fri Nov 5 16:31:28 UTC 2021 x86_64
Shell:	/bin/bash
PHP binary:	/usr/bin/php
PHP version:	7.4.29
php.ini used:	/etc/php/7.4/cli/php.ini
MySQL binary:	/usr/bin/mysql
MySQL version:	mysql  Ver 15.1 Distrib 10.5.16-MariaDB, for debian-linux-gnu (x86_64) using readline 5.2
SQL modes:	STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
WP-CLI root dir:	/srv/www/wordpress-one/public_html/wp-cli-dev/wp-cli
WP-CLI vendor dir:	/srv/www/wordpress-one/public_html/wp-cli-dev/wp-cli/vendor
WP_CLI phar path:	
WP-CLI packages dir:	/home/vagrant/.wp-cli/packages/
WP-CLI global config:	
WP-CLI project config:	/srv/www/wordpress-one/public_html/wp-cli-dev/scaffold-command/wp-cli.yml
WP-CLI version:	2.7.0-alpha

Provide a possible solution

Provide additional context/Screenshots
Is partially related to #251 as @michaelandre0 already spotted this and I ran into the same situation fixing the path issue. </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes --activate fails after running second time if theme_slug and theme_name are different. #306

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