[BUG][GO] Pass by value/Pass by Reference changes breaking Go client

[meghana-rajashekar]

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?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

The commit in the PR: #8491 which resolves the pointer issue missed the logic to perform similar operation in case of Unmarshalling of the JSON.
Link to commit: aeneasr@0c5e5ae
Due to this, there is a mismatch between the data type for BreedList property(This issue is seen for array of object type property) between Dog type and DogWithoutEmbeddedStruct type(Present inside UnmarshalJSON() method).
Following is the model schema used to reproduce the issue.

Snippet of spec file

schemas:
    Dog:
      allOf:
        - $ref: '#/components/schemas/Animal'
        - type: object
          properties:
            legs:
               $ref: '#/components/schemas/Legs'
            breedList:
               type: array
               items:
                   description: A dimension value matching search query
                   type: object
    Cat:
      allOf:
        - $ref: '#/components/schemas/Animal'
        - type: object
          properties:
            declawed:
              type: boolean
            legs:
               $ref: '#/components/schemas/Legs'
    Legs:
        type: object
        required:
        - legs
        properties:
            legs:
              enum:
              - '2'
              - '4'
              default: '4'
              x-enum-as-string: true
            name:
               type: string
    Animal:
      type: object
      discriminator:
        propertyName: className
      required:
        - className
      properties:
        className:
          type: string
        color:
          type: string
          default: red
        run:
           type: boolean
           default: True
           readOnly: true
        results:
            type: array
            items:
                type: object

The following Snippet of code is generated:
Definition for {{ classname }} struct generated at the beginning:

type Dog struct {
        Animal
        Legs *Legs `json:"legs,omitempty"`
        BreedList []map[string]interface{} `json:"breedList,omitempty"`
        AdditionalProperties map[string]interface{}
}

Definition of struct generated inside UnmarshalJSON() method:

type DogWithoutEmbeddedStruct struct {
        Legs *Legs `json:"legs,omitempty"`
        BreedList *[]map[string]interface{} `json:"breedList,omitempty"`
}

We can see that there is the difference between the type of BreedList inside Dog(which is a non-pointer type) and DogWithoutEmbeddedStruct type(Which is a pointer type).

Expected output:

No issues when the code is built.

Actual output:

go build -o myproject
./model_dog.go:149:20: cannot use varDogWithoutEmbeddedStruct.BreedList (type *[]map[string]interface {}) as type []map[string]interface {} in assignment

openapi-generator version

5.2.1

OpenAPI declaration file content or url

https://gist.githubusercontent.com/the-akhil-nair/ffd8a387e24e90b8759bc7a3f53fe0f0/raw/c69c490139a95351df5e03ff1a40e9099e0e0782/go_pbv_pbv_petstore_example.yaml

Generation Details

config.yaml file content:

# Golang Configuration
enumClassPrefix: true
useOneOfDiscriminatorLookup: true
# Enable additionalProperties by default
additionalProperties:
    disallowAdditionalPropertiesIfNotPresent: false

java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -i https://gist.githubusercontent.com/the-akhil-nair/ffd8a387e24e90b8759bc7a3f53fe0f0/raw/c69c490139a95351df5e03ff1a40e9099e0e0782/go_pbv_pbv_petstore_example.yaml -g go -o ../animal -c ../config.yaml

Steps to reproduce

1. Pull the master branch and compile the openapi-generator code using mvn.
2. Run generation cli commands as mentioned in the above steps.
3. Change the directory to ../animal and run go build -o myproject

Related issues/PRs

#8491

Suggest a fix

The logic used to define the struct for classname should also be reflected when it's defined for WithoutEmbeddedStruct inside UnmarshalJSON() method.

PR raised for the solution:
#11466