[GENERAL] parameter name seems to be parsed as case insensitive

Description

In a paramater, if the case-insensitive form of its name is the same as the schema name (in the example, the parameter name is archiveType, the schema name is ArchiveType), the generator will stuck and give an error after a while:

Exception in thread "Thread-1" java.lang.OutOfMemoryError: Java heap space
        at java.util.Arrays.copyOf(Unknown Source)
        at java.util.ArrayList.grow(Unknown Source)
        at java.util.ArrayList.ensureExplicitCapacity(Unknown Source)
        at java.util.ArrayList.ensureCapacityInternal(Unknown Source)
        at java.util.ArrayList.add(Unknown Source)
        at io.swagger.codegen.v3.generators.DefaultCodegenConfig.fixUpParentAndInterfaces(DefaultCodegenConfig.java:308)
        at io.swagger.codegen.v3.generators.DefaultCodegenConfig.postProcessAllCodegenModels(DefaultCodegenConfig.java:279)
        at io.swagger.codegen.v3.generators.DefaultCodegenConfig.postProcessAllModels(DefaultCodegenConfig.java:271)
        at io.swagger.codegen.v3.DefaultGenerator.generateModels(DefaultGenerator.java:405)
        at io.swagger.codegen.v3.DefaultGenerator.generate(DefaultGenerator.java:779)
        at io.swagger.codegen.v3.cli.cmd.Generate.run(Generate.java:388)
        at java.lang.Thread.run(Unknown Source)

The OpenAPI Specs defined that name should be case-sensitive (https://swagger.io/specification/#parameter-object).

The example specs file works in swagger ui, but not in the generator. I also tested it with swagger validator and it can pass the test.

So I guess the generator parse it as case-insensitive and it's a bug?

Swagger-codegen version

3.0.30 (the eariler versions also have this issue)

Swagger declaration file content or url

https://gist.github.com/tc-imba/76dc7e627a56ac84b5c1c14b08d90f1e

{
  "openapi": "3.0.2",
  "info": {
    "title": "test",
    "description": "test",
    "version": "0.1.0"
  },
  "paths": {
    "/": {
      "get": {
        "summary": "test",
        "operationId": "test",
        "parameters": [
          {
            "required": false,
            "schema": {
              "allOf": [
                {
                  "$ref": "#/components/schemas/ArchiveType"
                }
              ],
              "default": "zip"
            },
            "name": "archiveType",
            "in": "query"
          }
        ],
        "responses": {
          "200": {
            "description": "Successful Response",
            "content": {
              "application/json": {
                "schema": {
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "ArchiveType": {
        "title": "ArchiveType",
        "enum": [
          "zip",
          "tar",
          "unknown"
        ],
        "type": "string",
        "description": "An enumeration."
      }
    }
  }
}

Command line used for generation

java -jar swagger-codegen-cli-3.0.30.jar generate -i openapi.json -o build/client/java -l python

I tried some other languages but the same error occurs. So I think it's a general problem on the parser.

Steps to reproduce

Run the command with openapi.json can reproduce this.

Related issues/PRs

Suggest a fix/enhancement

I'll work on a fix if possible, but I'm not very familiar with Java so it may take some time.

Start by reproducing the failure with the supplied openapi.json and generation command, then inspect DefaultCodegenConfig.fixUpParentAndInterfaces and the surrounding model post-processing calls shown in the stack trace. Done means generation terminates without the OutOfMemoryError while treating the parameter and schema names according to the OpenAPI case-sensitive rule.