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[BUG] ELM: C# 8 nullable feature creates uncompilable (Maybe OneOf<PContactInfo>) #4450
Description
Bug Report Checklist
- Have you provided a full/minimal spec to reproduce the issue?
No, it is the complete swagger.json - Have you validated the input using an OpenAPI validator (example)?
Yes - What's the version of OpenAPI Generator used?
4.2.0 - Have you search for related issues/PRs?
Yes. - What's the actual output vs expected output?
- [Optional] Bounty to sponsor the fix (example)
Description
As of C# 8, nullable references types have an anotation '?', and unless it is there, the reference cannot be null.
https://docs.microsoft.com/en-us/dotnet/csharp/tutorials/nullable-reference-types
I have a plain DTO like this,
public class AccResponse
{
// ReSharper disable once NotNullMemberIsNotInitialized
[NotNull] [Required] public BaseResponse Common { get; set; } = new BaseResponse();
// public string Id { get; set; }
[Required] public string Name { get; set; } = "";
public bool AllowGuest { get; set; }
public PContactInfo? TechContactInfo { get; set; }
public PContactInfo? AdminContactInfo { get; set; }
public bool Blocked { get; set; }
public bool Disabled { get; set; }
public int MaximumAllowedNamedUsers { get; set; }
public string? CreateUserEmailMessage { get; set; }
public string? CreateUserEmailMessageSubject { get; set; }
}
and the problem is
public PContactInfo? TechContactInfo { get; set; }
It is actually exactly the same as
public PContactInfo TechContactInfo { get; set; }
in C# 7 and earlier, i.e. since there is no [Required], that field can be null.
openapi-generator version
4.2.0
OpenAPI declaration file content or url
Command line used for generation
java -jar openapi-generator-cli-4.2.0.jar generate -g elm -i swagger.json -o src/Swagger/
Steps to reproduce
Just generate and look at the code. There is a warning for another problem,
[main] INFO o.o.codegen.DefaultGenerator - Model ExcelFormattingBase not generated since it's a free-form object
but you can ignore that. I can simplify those objects.
Suggest a fix
Just make it be treated as if neither ? or [Required] is not there.
Activity
auto-labeler commentedon Nov 11, 2019
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mattiasw2 commentedon Nov 11, 2019
Notice that
string?are correctly handled:mattiasw2 commentedon Nov 11, 2019
The nullable mark ? is the problem. I removed it, and the swagger.json file lost the following. So, for now, I will just make sure I do not use that annotation in my DTO classes.
eriktim commentedon Nov 12, 2019
Thanks for your report @mattiasw2.
oneOfis currently not yet supported, see #4434. However, I checked it and it does not work when theoneOfis inline in that PR. You would have to create a new schema in components for it.Two questions:
oneOfhere. You only have one case;nullableinstead ofrequiredhere?For now using
nullableand$refshould work.mattiasw2 commentedon Nov 13, 2019
The OneOf is generated by NSwag. I added this question there.
RicoSuter/NSwag#2435
mattiasw2 commentedon Nov 13, 2019
When I look at the specification of OneOf at https://swagger.io/docs/specification/data-models/oneof-anyof-allof-not/ it seems to me that adding a OneOf with just one option is useless. I think in this case, you can just remove the OneOf and replace the expression by the single $ref inside.
eriktim commentedon Nov 16, 2019
Yes exactly. That's why I wonder why it is generated like take. Nevertheless it should work though. It should create a custom type with only one variant.
mattiasw2 commentedon Nov 16, 2019
I think Rico from Nswag has says it should look like this, but I am not sure.
Currently, your generated code will be non-compilable, since the name of the type name includes & and ;
OneOf<PContactInfo>
pekunicki commentedon Mar 18, 2020
Hi All, @mattiasw2 did you maybe find some workaround for that?
This oneOf for one nullable referenced object is slightly confusing.
mattiasw2 commentedon Mar 18, 2020
@pekunicki I choose to not use the C# 8 nullable feature in my API. The reason I created this ticket is that Typescript handled it, and in the long-term I want ELM to support it too, since for a language like ELM, not-nullable is really important and useful.
pekunicki commentedon Mar 19, 2020
@mattiasw2 thanks, It seems like a more complex discussion, i.e. whether referenced objects can have nullable prop on the same level. See #5180