Finding WordPress posts still using the Classic Editor

Block Editor was introduced 7 years ago (geez, time sure flies), and you might’ve resisted for a while, but eventually you probably realized that Block Editor isn’t so bad, after all. In fact, classic editor posts nowadays tend to look horribly with modern themes, so at one point you probably also realized you should convert the existing classic pages to blocks.

Unfortunately this is mostly trial-n-error, so it needs manual labor. For instance, if your code blocks contain lines that have square brackets (such as all INI files), e.g.:

[foo]
bar

[foo2]
bar2

The built-in classic-to-block converter would turn the 2nd section into an unknown shortcode. Ouch. Also, images would have empty newlines below them. Same for the last line of code blocks, too. So yeah, the converter needs babysitting, you need to do it one by one, assuming you want to ensure a flawless conversion.

The problem is, WordPress doesn’t make it easy to find the posts that still remain. Apparently you need some coding for this. So install the Code Snippets plugin, head over to the newly added Snippets menu, and click Add New. Name it however you like, e.g. Find Classic Posts, and add the following:

// Add column
function add_editor_filter($columns)
{
	$columns['editor_type'] = 'Editor Type';
    return $columns;
}

// Populate column
function check_editor_type($column, $post_id)
{
    if ($column === 'editor_type')
	{
        $content = get_post_field('post_content', $post_id);
        echo (strpos($content, '<!-- wp:') === false) ? 'Classic' : 'Block';
		echo " Editor";
    }
}

// Apply the filters to Pages and Posts in admin panel
add_filter('manage_pages_columns', function($columns) { return add_editor_filter($columns); });
add_filter('manage_posts_columns', function($columns) { return add_editor_filter($columns); });

add_action('manage_pages_custom_column', function($column, $post_id) { check_editor_type($column, $post_id); }, 10, 2);
add_action('manage_posts_custom_column', function($column, $post_id) { check_editor_type($column, $post_id); }, 10, 2);

// Add column
function add_editor_filter($columns)
{
	$columns['editor_type'] = 'Editor Type';
    return $columns;
}

// Populate column
function check_editor_type($column, $post_id)
{
    if ($column === 'editor_type')
	{
        $content = get_post_field('post_content', $post_id);
        echo (strpos($content, '<!-- wp:') === false) ? 'Classic' : 'Block';
		echo " Editor";
    }
}

// Apply the filters to Pages and Posts in admin panel
add_filter('manage_pages_columns', function($columns) { return add_editor_filter($columns); });
add_filter('manage_posts_columns', function($columns) { return add_editor_filter($columns); });

add_action('manage_pages_custom_column', function($column, $post_id) { check_editor_type($column, $post_id); }, 10, 2);
add_action('manage_posts_custom_column', function($column, $post_id) { check_editor_type($column, $post_id); }, 10, 2);

Save and Activate the snippet, and your post lists should show the type just fine:

Cheers!