[Server] Add autoload check for enum types in ReferenceHandler

[joshuatam]

Motivation and Context

Some old framework is using autoload to include with the typeName directly, e.g. include(ini.php) when the typeName is ini.

If the typeName is the arbitrary type, set autoload in enum_exists to false

How Has This Been Tested?

Yes

Breaking Changes

No

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

None

[chr-hertel]

Hey @joshuatam, thanks for reaching out and bringing the patch. Can you help me understand the issue here? What's happening without this patch?
E.g. what's the error you're running into - is there a way to reproduce that?

[joshuatam]

Hey @joshuatam, thanks for reaching out and bringing the patch. Can you help me understand the issue here? What's happening without this patch? E.g. what's the error you're running into - is there a way to reproduce that?

I am integrating the sdk with Yii1, in which it will throw an error when reading Elements classes, e.g.

/**
 * Adds two numbers together.
 *
 * @param int $a The first number
 * @param int $b The second number
 * @return int The sum of the two numbers
 */
#[McpTool]
public function add(int $a, int $b): int
{
    return $a + $b;
}

And the error is

include(int.php): Failed to open stream: No such file or directory

[chr-hertel]

I'm really not sure that this is an error on library side, but rather something your autoloader should catch? are you using composer or sth custom?

[Nyholm]

Can we do something like this?

Ie, if it is an int, we would never call enum_exists().

Suggested change

	$shouldAutoload = !in_array($typeName, ['int', 'float', 'string', 'bool', 'array', 'object', 'callable', 'iterable', 'mixed', 'void', 'null', 'false', 'true', 'never']);
	if (enum_exists($typeName, $shouldAutoload)) {
	if ($type->isBuiltin() === false && enum_exists($typeName)) {

https://www.php.net/manual/en/language.types.type-system.php