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Exceptions inheriting from ValidationError raised in dec_hook implicitly wrapped in another ValidationError post 0.21.0 #1012
Description
Description
Pre 0.21.0, this would raise SomeError directly, now it raises msgspec.ValidationError with SomeError as a cause:
import msgspec
class SomeError(msgspec.ValidationError):
pass
class Foo:
pass
def dec_foo(tp, val):
raise SomeError()
try:
msgspec.convert("", type=Foo, dec_hook=dec_foo)
except Exception as exc:
print(type(exc))I believe this was an unintended side-effect of #790.
I'm not sure if this is desirable or not. It is however a breaking change
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provinzkraut commentedon Apr 10, 2026
I believe the issue is with the logic for how
dec_hookerrors are handled. According to the docs:Since
ValidationErrors are now alsoValueErrors, they will get wrapped again. IMO we should add a guard there, that lets those bubble up unchanged as before, as raising aValidationErroris most likely intentional by the user.fix wrapping `ValidationError` and `DecodeError` in `ValidationError`…