[BUG][Python] deepObject parameter style creates invalid code on 5.0.1 and raises exception on 5.1.1

[RonnyPfannschmidt]

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?

Description

when having a spec with deep objects parameter style, the python codegen creates invalid code on generator 5.0.x and fails altogether on generator 5.1.x

on 5.0.x the bad code generated looks like
api_50/api/hosts_api.py:from api_50.model.str_bool_date_datetime_dict_float_int_list_str_none_type import StrBoolDateDatetimeDictFloatIntListStrNoneType

on 5.1.x even considering them triggers

[main] ERROR o.o.codegen.DefaultCodegen - Undefined property/schema for `filter`. Default to type:string.
[main] ERROR o.o.codegen.DefaultCodegen - Undefined property/schema for `filter`. Default to type:string.
Exception in thread "main" java.lang.RuntimeException: Could not process operation:

openapi-generator version

• 5.1.1
• 5.0.1

OpenAPI declaration file content or url

api spec

relevant item is a used

components:
  parameters:
    filter_param:
      in: query
      name: filter
      required: false
      style: deepObject
      explode: true
      schema:
       type: object

Generation Details/ steps to reproduce

• log with 5.0.1
• log with 5.1.1

Related issues/PRs

i haven't found anything quite related

Suggest a fix

my current workaround is to use 5.1.x templates , the 5.0.x codegen and to post-process the generated files dropping the bad lines
it would be nice if there was a configuration option to set a deep_object_hook so users can provide a own serialization/de-serialization for deep_objects

[spacether]

How about instead implementing proper serialization/deserialization for deepobject?
Sadly, I don't think that our python generator has kept up with the openpapi options for parameter serialization.

[RonnyPfannschmidt]

@spacether it's on the mid term agenda for me, as a starting point I want don't crash at gen time and a option to configure the serializer

We also need the sercer/connexion side at some point

[spacether]

Doesn't openapi define what deepobject should do? Do you have a use case where you need to customize how it behaves?

[RonnyPfannschmidt]

@spacether deepObject is an utterly painful "standard" left for implementations, there are some non-formal ones for php/ruby, but there is no implementation for python that's standardized, so is not something i will start soon as it will need a good setup to be sane

also i don't want to just put a parser hack into openapi-codegen sincei ts jsut going to be a mess then

[kevinkirkup]

Any update on this?

[spacether]

No one has written this feature yet. If you want it, please consider writing a PR adding it in python-experimental
QueryParameter.__serialize_deep_object

One could implement it the same way that other libraries do per here: OAI/OpenAPI-Specification#1706
@kevinkirkup I pointed you at the python-experimental generator, not the python generator because python-experimental has serialization/deserialization code much more cleanly structured.
You posted a python generator stack trace which is different.

[kevinkirkup]

I don't mind updating the template, but I don't have an environment to fix the exception being thrown:

1  Exception: null
2        at org.openapitools.codegen.DefaultGenerator.processOperation(DefaultGenerator.java:1159)
3        at org.openapitools.codegen.DefaultGenerator.processPaths(DefaultGenerator.java:1050)
4        at org.openapitools.codegen.DefaultGenerator.generateApis(DefaultGenerator.java:549)
5        at org.openapitools.codegen.DefaultGenerator.generate(DefaultGenerator.java:891)
6        at org.openapitools.codegen.cmd.Generate.execute(Generate.java:441)
7        at org.openapitools.codegen.cmd.OpenApiGeneratorCommand.run(OpenApiGeneratorCommand.java:32)
8        at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:66)
9  Caused by: java.lang.NullPointerException
10        at org.openapitools.codegen.languages.PythonClientCodegen.fromProperty(PythonClientCodegen.java:440)
11        at org.openapitools.codegen.DefaultCodegen.fromParameter(DefaultCodegen.java:4752)
12        at org.openapitools.codegen.DefaultCodegen.fromOperation(DefaultCodegen.java:4113)
13        at org.openapitools.codegen.DefaultGenerator.processOperation(DefaultGenerator.java:1127)

https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java#L440

[kevinkirkup]

Example OpenAPI.json schema that shows this issue.
https://gist.github.com/kevinkirkup/5820d8db926f07b6eaa833394a21504c

[kevinkirkup]

May also be related to #11234

[spacether]

@kevinkirkup my PR will fix the NPE issue but does not add the deep object serialization