swagger-api/swagger-codegen

Swagger codegen generates a nullable integer as method return value in SDK for operation that returns an integer

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#6,872 opened on Nov 2, 2017

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Client: C-SharpEnhancement: GeneralGeneral: Questionhelp wanted

Description

Description

I have an operation which returns an integer, and when I generate a C# SDK using codegen, the method associated with the operation returns a nullable integer instead of an integer. I tried to set the produced response schema as required using an operation filter and setting the default value as 0 but it had no effect.

Here is the definition of my operation responses:

       "responses":{  
           "200":{  
              "description":"Success",
              "schema":{  
                 "format":"int32",
                 "default":0,
                 "required":[  
                    "200"
                 ],
                 "type":"integer"
              }
           }
        }

Thank you for any insight

Contributor guide

Tech stack
csharprest api
Domain
backendapi
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Basic C# knowledgeUnderstanding of OpenAPI spec
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the C# codegen templates (e.g., in modules/swagger codegen/src/main/resources/csharp/) to understand how nullable type is determined for integer responses. Look at how the 'required' property in the response schema is handled in the template logic. The issue may require adding a check to ensure non nullable types are used when 'required' is set or when a default value is present. Review the mustache templates and the Java code that processes the schema to fix the mapping.