0.288.0.mdx

slug	breaking-changes/0.288.0
title	0.288.0 Breaking Changes

v0.288.0 Breaking Changes

This release deprecates passing a class (or type) to strawberry.scalar(). Use scalar_map in StrawberryConfig instead.

Deprecated: strawberry.scalar(cls, ...)

The pattern of wrapping a type with strawberry.scalar() is deprecated:

# Deprecated
Base64 = strawberry.scalar(
    NewType("Base64", bytes),
    serialize=lambda v: base64.b64encode(v).decode(),
    parse_value=lambda v: base64.b64decode(v),
)

Instead, use scalar_map in StrawberryConfig:

# Recommended
from typing import NewType
from strawberry.schema.config import StrawberryConfig

Base64 = NewType("Base64", bytes)

schema = strawberry.Schema(
    query=Query,
    config=StrawberryConfig(
        scalar_map={
            Base64: strawberry.scalar(
                name="Base64",
                serialize=lambda v: base64.b64encode(v).decode(),
                parse_value=lambda v: base64.b64decode(v),
            )
        }
    ),
)

This approach provides better type checking support because your custom scalar stays a proper type that type checkers (mypy, pyright, ty) can understand. The previous pattern of wrapping types with strawberry.scalar() returned a ScalarWrapper object, which type checkers could not use as a valid type annotation, causing errors like "Variable not allowed in type expression".

Removed: Scalar wrapper exports

The scalar wrapper exports (Date, DateTime, Time, Decimal, UUID, Void) from strawberry.schema.types.base_scalars have been removed. Use standard Python types directly instead (datetime.date, datetime.datetime, etc.).

A codemod is available: strawberry upgrade replace-scalar-wrappers .