Open
Description
Description
When using a fixed-length tuple type hint like tuple[int, int, int] within a data structure (e.g., msgspec.Struct) returned by a route handler, the generated OpenAPI schema for that field is incorrect. Instead of defining the type for each item position using the array form of items, it generates a schema with "items": {"oneOf": [...]} containing redundant type definitions.
Example:
class Color(Struct):
rgb: tuple[int, int, int]Actual Behavior:
The generated OpenAPI schema within components.schemas.Color.properties.rgb is:
{
"rgb": {
"items": {
"oneOf": [
{
"type": "integer"
},
{
"type": "integer"
},
{
"type": "integer"
}
]
},
"type": "array"
}
}It should be:
{
"rgb": {
"type": "array",
"items": [ // Array form to define types per position
{ "type": "integer" }, // Type for index 0
{ "type": "integer" }, // Type for index 1
{ "type": "integer" } // Type for index 2
],
}
}URL to code causing the issue
No response
MCVE
from litestar import Litestar, get
from litestar.openapi.config import OpenAPIConfig
from litestar.openapi.plugins import ScalarRenderPlugin
# Assuming Struct is from msgspec, adjust if it's different
from msgspec import Struct
# Define the data structure
class Color(Struct):
rgb: tuple[int, int, int]
# Define the route handler
@get("/", sync_to_thread=True)
def test() -> Color:
# Return an instance matching the Color structure
return Color(rgb=(255, 0, 0))
# Configure the Litestar app with OpenAPI
app = Litestar(
[test],
lifespan=[],
debug=True,
openapi_config=OpenAPIConfig(
render_plugins=[ScalarRenderPlugin()],
title="My API",
version="1.0.0",
),
)Litestar Version
litestar[standard]>=2.15.2
Platform
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