Plugin installation and activation in Wordpress - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens after activating a WordPress plugin?

After you activate a plugin in WordPress, what is the immediate effect on the website?

A The website automatically updates to the latest WordPress version.

B The plugin files are deleted from the server to save space.

C The WordPress core files are replaced with the plugin's files.

D The plugin's code starts running and can add features or change site behavior immediately.

💡 Hint

Think about what activating a plugin means for the website's functionality.

Activating a plugin loads its code so it can add features or modify the site. It does not delete files or update WordPress itself.

📝 Syntax

intermediate

Which code snippet correctly activates a plugin programmatically?

In WordPress, which PHP code correctly activates a plugin named 'my-plugin/my-plugin.php'?

A wp_activate_plugin('my-plugin/my-plugin.php');

B activate('my-plugin/my-plugin.php');

C activate_plugin('my-plugin/my-plugin.php');

D plugin_activate('my-plugin/my-plugin.php');

💡 Hint

Look for the official WordPress function to activate plugins.

The correct function is activate_plugin(). Other options are not valid WordPress functions.

🔧 Debug

advanced

Why does this plugin activation fail with a fatal error?

Given this plugin main file code, why does activating it cause a fatal error?

<?php
function my_plugin_init() {
  echo $undefined_variable;
}
add_action('init', 'my_plugin_init');

A Because $undefined_variable is not defined, causing a PHP notice but not a fatal error.

B Because echo cannot be used inside functions hooked to 'init'.

C Because using an undefined variable in echo causes a fatal error during activation.

D Because add_action is called before WordPress is fully loaded.

💡 Hint

Think about what happens when PHP tries to echo a variable that does not exist.

Using an undefined variable in echo causes a PHP notice, but not a fatal error, so the plugin activation should not fail fatally for this reason.

❓ state_output

advanced

What is the value of 'active_plugins' option after activating two plugins?

Assuming the 'active_plugins' option initially is an empty array, what will it contain after activating these two plugins?

activate_plugin('plugin-one/plugin-one.php');
activate_plugin('plugin-two/plugin-two.php');
$active = get_option('active_plugins');

A ['plugin-two/plugin-two.php']

B ['plugin-one/plugin-one.php', 'plugin-two/plugin-two.php']

C []

D ['plugin-one/plugin-one.php']

💡 Hint

Activating plugins adds them to the active plugins list.

Each activated plugin is added to the 'active_plugins' option array, so both plugins appear in the list.

🧠 Conceptual

expert

Which hook runs only once immediately after plugin activation?

Which WordPress hook is designed to run only once right after a plugin is activated?

A register_activation_hook

B wp_loaded

C plugins_loaded

D init

💡 Hint

Think about the special hook used to run setup code when a plugin is activated.

register_activation_hook runs only once immediately after plugin activation to perform setup tasks.