OpenAPI HashSets doesn't generate correctly

[niemyjski]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

HashSets doesn't generate correctly as it should include "uniqueItems": true. See SampleModel.ShouldHaveUniqueItemsTrue prop.

Expected Behavior

These should just work out of the box.

Steps To Reproduce

Clone https://github.com/exceptionless/aspnet-core-net10-issues# and run it, hit the open api json endpoint.

Exceptions (if any)

No response

.NET Version

10 preview 6

Anything else?

MacOS Latest, Rider/VS Code

#62150

[captainsafia]

STJ isn't generating uniqueItems for the type here, likely because it doesn't enforce this constraint in its own serialization layer. PRs welcome for a fix for this. Absent that, a schema transformer is available as an option.

[martincostello]

For Swashbuckle we do this:

    private OpenApiSchema CreateArraySchema(DataContract dataContract, SchemaRepository schemaRepository)
    {
        var hasUniqueItems =
            dataContract.UnderlyingType.IsConstructedFrom(typeof(ISet<>), out _) ||
            dataContract.UnderlyingType.IsConstructedFrom(typeof(KeyedCollection<,>), out _);


        return new OpenApiSchema
        {
            Type = JsonSchemaTypes.Array,
            Items = GenerateSchema(dataContract.ArrayItemType, schemaRepository),
            UniqueItems = hasUniqueItems ? true : null
        };
    }

[niemyjski]

Thanks for both of your replies! Would you want a pr with a schema transformer or how do you see this implemented? Also, I hope the bot doesn't close this after 24 hours....

[martincostello]

The bot closes issues when the resolved label is added.

[martincostello]

how do you see this implemented

My initial hunch would be something in JsonNodeSchemaExtensions to apply the uniqueItems property (after being added to OpenApiSchemaKeywords) based on inspecting the runtime type of the schema, then somewhere in OpenApiSchemaService being updated to call that new method.