Deprecate TypedExpression in favor of ExpressionWithReturnType

[GromNaN]

Improvement

Q	A
New Feature	no
RFC	no
BC Break	no

Follow-up to this comment.

• Replace static Type::* calls with instance-based TypeRegistry lookups #12421

History

The TypedExpression interface was introduced in December 2019 (commit 24e9a7c, issue #7941) to let DQL functions declare their scalar return type. At the time, DBAL 2.x exposed Type::getName() on the instance, so SqlWalker cheaply extracted the name via \$expr->getReturnType()->getName(). Returning a Type object was the natural handle for "a type" and required no static lookup on the walker side.

DBAL 4 removed Type::getName() in favour of TypeRegistry::lookupName($type). SqlWalker had to reach for Type::getTypeRegistry()->lookupName(...), and implementers had to keep calling the static Type::getType(Types::INTEGER) to hand back a Type instance the walker only uses to extract a name. The round-trip is vestigial, and it pins two static Type::* calls that block the instance-based type registry work in #12421.

Solution

Introduce a new interface Doctrine\ORM\Query\AST\ExpressionWithReturnType that exposes the DBAL type name directly. TypedExpression is deprecated; SqlWalker prefers the new interface, falls back to the legacy one with a runtime deprecation, and finally to the historical 'string' default.

Upgrade

Before:

use Doctrine\DBAL\Types\Type;
use Doctrine\DBAL\Types\Types;
use Doctrine\ORM\Query\AST\TypedExpression;

class MyFunction extends FunctionNode implements TypedExpression
{
    public function getReturnType(): Type
    {
        return Type::getType(Types::INTEGER);
    }
}

After:

use Doctrine\DBAL\Types\Types;
use Doctrine\ORM\Query\AST\ExpressionWithReturnType;

class MyFunction extends FunctionNode implements ExpressionWithReturnType
{
    public function getReturnTypeName(): string
    {
        return Types::INTEGER;
    }
}

[greg0ire]

Thanks @GromNaN !