Problem generating model(s) when schema has type: object with oneOf with single ref

[vipentti]

What are you generating using Kiota, clients or plugins?

API Client/SDK

In what context or format are you using Kiota?

Nuget tool

Client library/SDK language

Csharp

Describe the bug

We came across this when we were using Kiota to generate our C# client-code against a contract which was work in progress.

In the contract we are using we have several oneOf hierarchies and in one case there was a hierarchy where there was only a single ref under oneOf but the schema had type: object set. If the type: object is set, the contract does not generate the expected models.

I have a repository with the generated clients and example schemas which reproduce the issue available at https://github.com/vipentti/kiota-type-object-one-of-issue

Expected behavior

Kiota generates code for both schemas similarly (with or without type: object) because if the type: object is present with multiple oneOf refs, code is generated as expected.

    # ... rest of the schema ...
    # Does not work (Component1) is not generated at all or mentioned in the
    # generated ExampleWithSingleOneOfWithTypeObject type.
    ExampleWithSingleOneOfWithTypeObject:
      # Removing this works
      type: object
      oneOf:
        - $ref: "#/components/schemas/Component1"
      discriminator:
        propertyName: objectType

    # Does work (Component2) is generated but ExampleWithSingleOneOfWithoutTypeObject is not
    # e.g. Component2 is used in place of ExampleWithSingleOneOfWithoutTypeObject
    ExampleWithSingleOneOfWithoutTypeObject:
      oneOf:
        - $ref: "#/components/schemas/Component2"
      discriminator:
        propertyName: objectType
    # ... rest of the schema ...

How to reproduce

I have a repository with the generated clients and example schemas which reproduce the issue available at https://github.com/vipentti/kiota-type-object-one-of-issue

Open API description file

https://github.com/vipentti/kiota-type-object-one-of-issue/blob/main/DiscriminatorProblemSampleSimple.yaml

Kiota Version

1.20.0+81bdb1bf13383a749f794d47926d09733d2d7be1

Latest Kiota version known to work for scenario above?(Not required)

No response

Known Workarounds

Removing the type: object if there is only one oneOf seems to work, unfortunately that may not be possible if the schema is also generated by some tool and/or provided by 3rd parties.

Configuration

• OS: Window 10
• Architecture: x64

Debug output

Click to expand log

```

info: Kiota.Builder.KiotaBuilder[0]
Cleaning output directory <repo_path>\kiota-type-object-one-of-issue.\Generated\Simple\CSharp
dbug: Kiota.Builder.KiotaBuilder[0]
kiota version 1.20.0
info: Kiota.Builder.KiotaBuilder[0]
loaded description from local source
dbug: Kiota.Builder.KiotaBuilder[0]
step 1 - reading the stream - took 00:00:00.0050763
dbug: Kiota.Builder.KiotaBuilder[0]
step 2 - parsing the document - took 00:00:00.0679186
dbug: Kiota.Builder.KiotaBuilder[0]
step 3 - updating generation configuration from kiota extension - took 00:00:00.0000607
dbug: Kiota.Builder.KiotaBuilder[0]
step 4 - filtering API paths with patterns - took 00:00:00.0029692
info: Kiota.Builder.KiotaBuilder[0]
Client root URL set to https://mytodos.doesnotexist
dbug: Kiota.Builder.KiotaBuilder[0]
step 5 - checking whether the output should be updated - took 00:00:00.0074799
dbug: Kiota.Builder.KiotaBuilder[0]
step 6 - create uri space - took 00:00:00.0023193
dbug: Kiota.Builder.KiotaBuilder[0]
InitializeInheritanceIndex 00:00:00.0021671
warn: Kiota.Builder.KiotaBuilder[0]
Discriminator Component1 is not inherited from ExampleWithSingleOneOfWithTypeObject.
dbug: Kiota.Builder.KiotaBuilder[0]
CreateRequestBuilderClass 00:00:00
dbug: Kiota.Builder.KiotaBuilder[0]
MapTypeDefinitions 00:00:00.0034938
info: Kiota.Builder.KiotaBuilder[0]
Removing unused model Component1 as it is not referenced by the client API surface
dbug: Kiota.Builder.KiotaBuilder[0]
TrimInheritedModels 00:00:00
dbug: Kiota.Builder.KiotaBuilder[0]
CleanUpInternalState 00:00:00
dbug: Kiota.Builder.KiotaBuilder[0]
step 7 - create source model - took 00:00:00.0405963
dbug: Kiota.Builder.KiotaBuilder[0]
14ms: Language refinement applied
dbug: Kiota.Builder.KiotaBuilder[0]
step 8 - refine by language - took 00:00:00.0147122
dbug: Kiota.Builder.KiotaBuilder[0]
step 9 - writing files - took 00:00:00.0188196
info: Kiota.Builder.KiotaBuilder[0]
loaded description from local source
dbug: Kiota.Builder.KiotaBuilder[0]
step 10 - writing lock file - took 00:00:00.0083907
Generation completed successfully
Client base url set to https://mytodos.doesnotexist
dbug: Kiota.Builder.KiotaBuilder[0]
Api manifest path: <repo_path>\kiota-type-object-one-of-issue\apimanifest.json

Hint: use the info command to get the list of dependencies you need to add to your project.
Example: kiota info -d "<repo_path>\kiota-type-object-one-of-issue.\DiscriminatorProblemSampleSimple.yaml" -l CSharp

Hint: use the --include-path and --exclude-path options with glob patterns to filter the paths generated.
Example: kiota generate --include-path "**/foo" -d "<repo_path>\kiota-type-object-one-of-issue.\DiscriminatorProblemSampleSimple.yaml"

</details>


### Other information

_No response_