Search-replace does not replace keys in serialized values

Start in src/WP_CLI/SearchReplacer.php at lines 91-93 and reproduce the documented wp search-replace command against serialized wp_options data. Inspect how serialized array keys are traversed and consider the proposed --replace-keys behavior, including its unintended-consequence concern. Done means the expected sidebar key replacement is handled and covered by the relevant project tests.

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

When running a search-replace on the database and explicitly declaring --recurse-objects, the command does not change array keys in serialized strings, only array values. As such, keys get looked over and do not get correctly replaced by this command.

Note that this may also occur even if --recurse-objects is not explicitly declared, as it appears that this value is true even if not declared as per https://developer.wordpress.org/cli/commands/search-replace/.

Describe how other contributors can replicate this bug

• Do a basic install of WordPress 5.3.2
• Set up wp-cli 2.4.0
• Log in the WordPress site and activate the theme "Twenty Seventeen", then activate the theme "Twenty Twenty". This forces a write of the data for the theme to the wp_options table for the theme's customization information.
• Looking at the database, the wp_options table has an option_name value theme_mods_twentytwenty with an option_value like a:3:{s:18:"custom_css_post_id";i:-1;s:16:"sidebars_widgets";a:2:{s:4:"time";i:1585600348;s:4:"data";a:3:{s:19:"wp_inactive_widgets";a:0:{}s:9:"sidebar-1";a:4:{i:0;s:8:"search-2";i:1;s:14:"recent-posts-2";i:2;s:17:"recent-comments-2";i:3;s:10:"calendar-3";}s:9:"sidebar-2";a:3:{i:0;s:10:"archives-2";i:1;s:12:"categories-2";i:2;s:6:"meta-2";}}}s:18:"nav_menu_locations";a:0:{}}. We are particularly interested in the sidebar names, sidebar-1 and sidebar-2.
• In this particular case, say we have added a new sidebar location to the theme, but we do not want to have to re-add all of the widgets to this new sidebar. We want to do a rewrite of the sidebar key value for sidebar-1 to my-sidebar-1.
• Run wp search-replace "sidebar-1" "my-sidebar-1" --dry-run --all-tables.
• The results will not include any values in the wp_options table listed above.

Describe what you would expect as the correct outcome

When running the above described wp search-replace, it should also replace array keys in serialized string values.

Let us know what environment you are running this on

vagrant@ubuntu-bionic:/var/www/html$ wp --info
OS:	Linux 4.15.0-91-generic #92-Ubuntu SMP Fri Feb 28 11:09:48 UTC 2020 x86_64
Shell:	/bin/bash
PHP binary:	/usr/bin/php7.2
PHP version:	7.2.24-0ubuntu0.18.04.3
php.ini used:	/etc/php/7.2/cli/php.ini
WP-CLI root dir:	phar://wp-cli.phar/vendor/wp-cli/wp-cli
WP-CLI vendor dir:	phar://wp-cli.phar/vendor
WP_CLI phar path:	/var/www/html
WP-CLI packages dir:
WP-CLI global config:	/home/vagrant/.wp-cli/config.yml
WP-CLI project config:
WP-CLI version:	2.4.0

Provide a possible solution

The applicable section of the code appears to be https://github.com/wp-cli/search-replace-command/blob/master/src/WP_CLI/SearchReplacer.php#L91-L93

It would be necessary to alter this to also replace keys after the data had been searched and replaced.

Provide additional context/Screenshots

Replacing array keys may have unintended consequences, especially if the key exists elsewhere in the database in a place that the person running this command may be unaware of. Perhaps adding an option such as --replace-keys that will ONLY replace array keys in a search-replace?