[BUG] [Swift] Generating/Calling NSDecimalString function crashes the Swift compiler

[borsosbe]

Description

NSDecimalString generation causing a complier error after xCode beta 5 and 6.

The following code that calls NSDecimalString crashes the compiler with the message:

SILFunction type mismatch for 'NSDecimalString': '$@convention(c) (UnsafePointer, Optional) -> @autoreleased Optional' != '$@convention(c) (UnsafePointer, Optional) -> @autoreleased NSString'

swiftlang/swift#75752

See the issue in swift language repo. If the new xCode 16 stays that way, openapi should change is generation. There is a workaround on the issue which works.
It is currently a problem regardless of the beta, since developers have to adapt the new xCode beta to prepare for iOS 18 which is coming out soon.

openapi-generator version

7.8

OpenAPI declaration file content or url

Generation Details

openapi-generator generate
-i etc/xxxyaml
-g swift5
-o Sources/Packages/XXX
--global-property models,supportingFiles,modelDocs=false
--model-name-suffix=DTO
--additional-properties=projectName= XXX,swiftPackagePath=Sources,removeMigrationProjectNameClass=true

Steps to reproduce

Related issues/PRs

Suggest a fix

Problematic generation:
extension KeyedEncodingContainerProtocol { public mutating func encode(_ value: Decimal, forKey key: Self.Key) throws { var mutableValue = value let stringValue = NSDecimalString(&mutableValue, Locale(identifier: "en_US")) try encode(stringValue, forKey: key) } }

Workaround:
extension KeyedEncodingContainerProtocol { public mutating func encode(_ value: Decimal, forKey key: Self.Key) throws { let decimalNumber = NSDecimalNumber(decimal: value) let numberFormatter = NumberFormatter() numberFormatter.numberStyle = .decimal numberFormatter.locale = Locale(identifier: "en_US") let formattedString = numberFormatter.string(from: decimalNumber) ?? "\(value)" try encode(formattedString, forKey: key) } }

[aehlke]

please share the change as a PR, I'd love to have this... thanks

[borsosbe]

@aehlke Just generate your stuff that you normally do. Look for NSDecimalString in the generated code and implement the workaround from the example.

[r3econ]

We are experiencing the same problem. The issue is critical 🔴

[aehlke]

We are experiencing the same problem. The issue is critical 🔴

It has an easy workaround so I wouldn't call it critical at least - just drop in a template replacement

[lilidotshi]

Would also like to see a fix for this as we would like to rely on not having to update our generated code manually for CI.

[aehlke]

Would also like to see a fix for this as we would like to rely on not having to update our generated code manually for CI.

You don't need to manually change anything - override the specific template file in your automation

[lilidotshi]

@aehlke I opened up a PR with the changes that @borsosbe suggested here if you wanted to take a look. #19564

[4brunu]

I'm closing this issue, as this should now be fixed, if the issue is still present, please reopen this issue.
Thanks