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msgspec.Raw appears not to work with msgspec.yaml.decode #1136
Description
Question
I couldn't find any note in documentation suggesting msgspec.Raw cannot be used with YAML for decoding, so i assumed it is supported, but i get ValidationError. Is this expected behavior?
Minimal reproduction:
import msgspec
class Repro(msgspec.Struct):
tools: dict[str, msgspec.Raw]
for value in (
b"tools:\n x: 1\n",
b"tools:\n x: hello\n",
b"tools:\n x: [a, b]\n",
b"tools:\n x: {a: 1}\n",
b"tools:\n x:\n a: 1\n",
):
msgspec.yaml.decode(value, type=Repro)Result:
msgspec.ValidationError: Expected `any`, got `int` - at `$.tools[...]``
msgspec.ValidationError: Expected `any`, got `str` - at `$.tools[...]`
msgspec.ValidationError: Expected `any`, got `array` - at `$.tools[...]`
msgspec.ValidationError: Expected `any`, got `object` - at `$.tools[...]`
msgspec.ValidationError: Expected `any`, got `object` - at `$.tools[...]`
Environment:
- Python: 3.12.13 (main, May 10 2026, 19:30:01) [Clang 22.1.3 ]
- msgspec: 0.21.1
Activity
Brohammad commentedon Sep 2, 2026
This is expected with the current architecture:
msgspec.Rawneeds access to original serialized bytes, which only the nativejsonandmsgpackC decoders provide.yaml.decodeparses fully via PyYAML before validation, so byte spans are lost.Opened #1168 with:
Expected \any`, got `int``Brohammad commentedon Sep 2, 2026
Correction: PR is #1170 (not #1168).
fix: correct misleading "Expected any" error for Raw fields in conver…