msgspec

import msgspec

# Fix 1: Reorder fields
class ValidOrder(msgspec.Struct):
    a: str  # Required
    b: int = 0  # Optional

# Fix 2: Use kw_only=True
class KeywordOnly(msgspec.Struct, kw_only=True):
    a: str = "" # Optional, but position doesn't matter for kw_only
    b: int # Required

import msgspec

class User(msgspec.Struct):
    name: str
    groups: list[str] = msgspec.field(default_factory=list)

# Correct input: groups contains only strings
valid_data = b'{"name":"bob","groups":["devops"]}'
user = msgspec.json.decode(valid_data, type=User)
print(user)

# Original problematic input (assuming it contained an int where str was expected)
# invalid_data = b'{"name":"bob","groups":["devops", 123]}'
# try:
#     msgspec.json.decode(invalid_data, type=User)
# except msgspec.ValidationError as e:
#     print(e)

import msgspec
import numpy as np

# Original problematic code:
# mjson.encode(np.float64(1.0))

# Fix 1: Convert to a native Python float
value_np = np.float64(1.0)
encoded_data = msgspec.json.encode(float(value_np))
print(encoded_data)

# Fix 2: Use an enc_hook for custom handling
def numpy_encoder_hook(obj):
    if isinstance(obj, np.ndarray):
        return obj.tolist()
    if isinstance(obj, np.generic):
        return obj.item()
    raise NotImplementedError

encoder = msgspec.json.Encoder(enc_hook=numpy_encoder_hook)
encoded_data_with_hook = encoder.encode(np.array([1.0, np.float64(2.0)]))
print(encoded_data_with_hook)

import msgspec

class Point(msgspec.Struct, frozen=True):
    x: float
    y: float

p = Point(1.0, 2.0)

# Original problematic code:
# p.x = 2.0

# Fix: Create a new instance with updated values
p_new = Point(x=3.0, y=p.y) # Or use msgspec.structs.replace if you have many fields
print(p_new)

# If mutability is desired, define the struct without frozen=True
class MutablePoint(msgspec.Struct):
    x: float
    y: float
m_p = MutablePoint(1.0, 2.0)
m_p.x = 3.0
print(m_p)

import msgspec
from typing import Union

# Original problematic code:
# class TestData(msgspec.Struct):
#     content: Union[str, bytes]

# Fix 1: Use a single, unambiguous type
class TestDataStr(msgspec.Struct):
    content: str

class TestDataBytes(msgspec.Struct):
    content: bytes

# Fix 2: If you must handle both, define separate structs and use a Tagged Union
# This allows msgspec to differentiate between them
class MyStrData(msgspec.Struct, tag='str_data'):
    value: str

class MyBytesData(msgspec.Struct, tag='bytes_data'):
    value: bytes

class Wrapper(msgspec.Struct):
    data: Union[MyStrData, MyBytesData]

encoder = msgspec.msgpack.Encoder()
decoder = msgspec.msgpack.Decoder(Wrapper)

wrapped_str = Wrapper(MyStrData('hello'))
encoded_str = encoder.encode(wrapped_str)
decoded_str = decoder.decode(encoded_str)
print(decoded_str)

wrapped_bytes = Wrapper(MyBytesData(b'world'))
encoded_bytes = encoder.encode(wrapped_bytes)
decoded_bytes = decoder.decode(encoded_bytes)
print(decoded_bytes)