Sanitize theme slugs for usage in PHP function names

[Copilot]

Child theme slugs containing dots (e.g. twentytwentyfive-child-2.0.2) produced invalid PHP function names in the generated functions.php, since only spaces and hyphens were being replaced with underscores.

Changes

• src/Scaffold_Command.php: Replace str_replace( [ ' ', '-' ], '_', ... ) with preg_replace( '/[^a-zA-Z0-9_]/', '_', ... ) so that all non-identifier characters are sanitized, not just spaces and hyphens.
• features/scaffold.feature: Add a scenario asserting that a slug like my-theme-2.0.1 produces my_theme_2_0_1_parent_theme_enqueue_styles in both the function declaration and the add_action call.

Before:

// wp scaffold child-theme twentytwentyfive-child-2.0.2 --parent_theme=twentytwentyfive
add_action( 'wp_enqueue_scripts', 'twentytwentyfive_child_2.0.2_parent_theme_enqueue_styles' );
function twentytwentyfive_child_2.0.2_parent_theme_enqueue_styles() { ... }

After:

add_action( 'wp_enqueue_scripts', 'twentytwentyfive_child_2_0_2_parent_theme_enqueue_styles' );
function twentytwentyfive_child_2_0_2_parent_theme_enqueue_styles() { ... }

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[Copilot]

Pull request overview

This PR fixes child-theme scaffolding when the provided theme slug contains characters that are not valid in PHP function identifiers (e.g., dots in version-like slugs), ensuring the generated functions.php contains valid add_action() callbacks and function declarations.

Changes:

• Sanitize the child theme slug more broadly when generating the prefix_safe used in functions.php function names.
• Add an acceptance test scenario covering a dotted slug (e.g. my-theme-2.0.1) and asserting the generated callback/function name uses underscores.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/Scaffold_Command.php	Updates how prefix_safe is derived from the slug so generated PHP identifiers don’t contain invalid characters like .
features/scaffold.feature	Adds coverage to prevent regressions for dotted slugs in child-theme scaffolding

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[Copilot]

preg_replace( '/[^a-zA-Z0-9_]/', '_', $theme_slug ) still allows prefix_safe to start with a digit (e.g. slug 2.0-theme -> 2_0_theme), which would generate an invalid PHP function name and a parse error in the scaffolded functions.php. Consider additionally normalizing prefix_safe to ensure the first character is [A-Za-z_] (e.g. prefixing with _ or theme_ when it isn’t) and handling the edge case where the sanitized result becomes empty.

Suggested change

	$data['prefix_safe'] = preg_replace( '/[^a-zA-Z0-9_]/', '_', $theme_slug );
	$prefix_safe = preg_replace( '/[^a-zA-Z0-9_]/', '_', $theme_slug );
	if ( '' === $prefix_safe ) {
	$prefix_safe = 'theme';
	}
	if ( ! preg_match( '/^[A-Za-z_]/', $prefix_safe ) ) {
	$prefix_safe = '_' . $prefix_safe;
	}
	$data['prefix_safe'] = $prefix_safe;