[BUG] [C] enum name collision with latest

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• [ ] Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
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Description

I'm trying to generate C code for an API with a model (task) that has two enums in it (TaskType and TaskStatus)

I'm seeing name collisions in the generated output, similar to an older (fixed) bug BUG: 4293

Here is the generated model header: (model/task.h):

// Enum  for task

typedef enum  { fastapi_task__NULL = 0, fastapi_task__NIL, fastapi_task__DO_A, fastapi_task__DO_B, fastapi_task__DO_C } fastapi_task__e;

// ...

// Enum  for task

typedef enum  { fastapi_task__NULL = 0, fastapi_task__NIL, fastapi_task__NOT_APPROVED, fastapi_task__NOT_READY, fastapi_task__NOT_ASSIGNED, fastapi_task__PENDING, fastapi_task__EXECUTING, fastapi_task__DONE } fastapi_task__e;

The two enums collide both the the NIL and NULL enum value and the name of of the typedef (fastapi_task__e).

Looking at the model-header.mustache, I see:

// Enum {{enumName}} for {{classVarName}}
...

I would expect to see the {{enumName}} ("TaskType" or "TaskStatus" ) embedded in the names, which would fix them for uniqueness.

Is my yaml missing something?

openapi-generator version

openapi-generator-cli-7.9.0.jar

OpenAPI declaration file content or url

https://gist.github.com/PeteFlugstad/8ca8bd25a7aed7015b6634ddd77560c4

Generation Details

openapi-generator-cli-7.9.0.jar

Steps to reproduce

$ java -jar openapi-generator-cli-7.9.0.jar generate -i task.yaml -g c -o output
$ mkdir output/build
$ cd output/build
$ cmake ..
$ make

Related issues/PRs

https://github.com/OpenAPITools/openapi-generator/issues/4293

Suggest a fix

Seems like the {{enumName}} field is not being parsed or populated correctly from the yaml.

Start with model-header.mustache and the generated model/task.h shown in the report, then reproduce the issue using the openapi-generator-cli 7.9.0 command and the provided task.yaml. The work is done when TaskType and TaskStatus produce distinct enum values and typedef names, and the generated project passes cmake and make.