[Go] Duplicate constant names for enums with same values

[moser4035]

Description

I've defined enums that contain same values (see below)
The openapi-generator creates constants with the same names.
But this is not allowed and the code does not compile anymore.

I get an error like this:

previous declaration at ../go-client/model_color_primaries.go:18:28
../go-client/model_color_space.go:20:26: SMPTE170_M redeclared in this block

used openapi-generator version: 3.0.3

OpenAPI declaration file content or url

ColorSpace:
  title: ColorSpace
  enum:
  - UNSPECIFIED
  - SMPTE170M
  - SMPTE240M

ColorPrimaries:
  title: ColorPrimaries
  enum:
  - UNSPECIFIED
  - SMPTE170M
  - SMPTE240M

Generated Go code

file model_color_space.go:

        type ColorSpace string

        const (
	        UNSPECIFIED ColorSpace = "UNSPECIFIED"
	        SMPTE170_M ColorSpace = "SMPTE170M"
	        SMPTE240_M ColorSpace = "SMPTE240M"
        )

file model_color_primaries.go:

        type ColorPrimaries string

        const (
	        UNSPECIFIED ColorPrimaries = "UNSPECIFIED"
	        SMPTE170_M ColorPrimaries = "SMPTE170M"
	        SMPTE240_M ColorPrimaries = "SMPTE240M"
        )

Command line used for generation

java -jar /opt/openapi-generator-cli.jar generate -g go -i openapi.json -o /go/src/go-client

Suggest a fix/enhancement

Maybe this could be solved by adding a prefix to the constants of the enum

[grokify]

Good post @moser4035.

I've run into this in the past as well.

I've filed PR #542 against the 4.0.x branch because this is a braking change without fallback.

This only changes model.mustache as shown below. Everything else in the PR is for testing. Feel free to use this locally until this is shipped in a release.

https://github.com/OpenAPITools/openapi-generator/pull/542/files#diff-6403a68f6b1039398715805f9043d0a1

[grokify]

This also happens when the values are similar but have different non-punctuation characters:

Here is some test output:

type EnumClassAntiCollision string

// List of EnumClassAntiCollision
const (
	ABC EnumClassAntiCollision = "abc"
	ABC EnumClassAntiCollision = "_abc"
	ABC EnumClassAntiCollision = "-abc"
	ABC EnumClassAntiCollision = "(abc)"
)

go-swagger handles this by substituting characters for the punctuation including Minus for - and Nr for (). Of note it also only capitalizes the first letter.

type EnumClass string

const (
	// EnumClassAbc captures enum value "_abc"
	EnumClassAbc EnumClass = "_abc"
	// EnumClassMinusEfg captures enum value "-efg"
	EnumClassMinusEfg EnumClass = "-efg"
	// EnumClassNrXyz captures enum value "(xyz)"
	EnumClassNrXyz EnumClass = "(xyz)"
)

[unipark00]

Hi, I have encountered the same problem in generating go-server stub code.
I used sample yaml - openapi.yaml
https://raw.githubusercontent.com/OpenAPITools/openapi-generator/master/samples/openapi3/server/petstore/go-api-server/api/openapi.yaml

go/model_outer_enum_default_value.go:16:33: PLACED redeclared in this block
previous declaration at go/model_outer_enum.go:16:21
go/model_outer_enum_default_value.go:17:35: APPROVED redeclared in this block
previous declaration at go/model_outer_enum.go:17:23
go/model_outer_enum_default_value.go:18:36: DELIVERED redeclared in this block
previous declaration at go/model_outer_enum.go:18:24

1537 OuterEnum:
1538 enum:
1539 - placed
1540 - approved
1541 - delivered
1542 type: string

1550 OuterEnumDefaultValue:
1551 default: placed
1552 enum:
1553 - placed
1554 - approved
1555 - delivered
1556 type: string

Problem still exist?

[kanwar-saad]

I am using version 4.1.1 and I still see the same issue.

[mikecowgill]

I ran into this with 4.3.2 but see the option for enumClassPrefix which is disabled by default.

-p enumClassPrefix=true

fixed it for me

[snaka]

This problem is supposed to be solved by the enumClassPrefix option.

see: https://github.com/OpenAPITools/openapi-generator/blob/master/docs/generators/go-gin-server.md

[mlebihan]

No, I disagree. The handling of duplicated enums name isn't finish.

enumClassPrefix adds a prefix on every constant {{name}}:

{{#enumClassPrefix}}{{{classname.toUpperCase}}}_{{/enumClassPrefix}}{{name}} {{{classname}}} = {{{value}}}

so that if we have:

animals in openapi.yaml with: enums dog, sheep, bird
and
petsAccepted with: enums dog, cat

It will generate:

(
       ANIMALS_DOG = "dog"
       ANIMALS_SHEEP = "sheep"
       ANIMALS_BIRD = "bird"
)

and

(
       PETSACCEPTED_DOG = "dog"
       PETSACCEPTED_CAT = "cat"
)

That many developers, I think, would like to avoid, because it's heavy to use and not required for 3 enums name on 4 that aren't duplicated.

→ currently I encounter the problem at work: 15 enums names are duplicated among 1,000 and I don't want to prefix 985 enums names that don't require it.

And if enumClassPrefix is false, you cannot a wrong code being generated whatever.

---

I my mind, when enumClassPrefix is false, you have to prefix names that are really found duplicated:

(
       ANIMALS_DOG = "dog"
       SHEEP = "sheep"
       BIRD = "bird"
)

and

(
       PETSACCEPTED_DOG = "dog"
       CAT = "cat"
)