`omit_defaults` does not omit tuples and frozensets
jodal opened this issue · comments
Description
When a struct has omit_defaults=True
set, any fields defaulting to dict
, list
, or set
is omitted from the serialization, as described in the docs.
However, if one is using tuple
instead of list
and frozenset
instead of set
as default values, to make the struct as immutable as possible, those defaults are included in the encoded format.
I think that tuple
and frozenset
should be handled in the same way as dict
, list, and
setby
omit_defaultsand
repr_omit_defaults`.
Example
import msgspec
class Backpack(msgspec.Struct, omit_defaults=True):
a_list: list[str] = msgspec.field(default_factory=list)
a_tuple: tuple[str, ...] = msgspec.field(default_factory=tuple)
a_frozenset: frozenset[str] = msgspec.field(default_factory=frozenset)
instance = Backpack()
print(msgspec.json.encode(instance))
Output:
b'{"a_tuple":[],"a_frozenset":[]}'
Expected:
b'{}'
Thanks for opening this - this should be fixed by #653. Note that for these cases specifying the default value by value (rather than via default_factory
) already works:
import msgspec
class Backpack(msgspec.Struct, omit_defaults=True):
a_list: list[str] = []
a_tuple: tuple[str, ...] = ()
a_frozenset: frozenset[str] = frozenset()
instance = Backpack()
print(msgspec.json.encode(instance))
#> b'{}'
The reason tuple
and frozenset
are the special cases here is that they're both immutable types and may always be specified by value. Since there's no functional reason to use a default_factory
for these types, we hadn't implemented the logic to check for equivalent defaults based on default_factory
for tuple
/frozenset
.
Thank you for the very swift fix! Especially useful with the tip on how to achieve this without waiting for a new release :-)