[BUG] [Go] [Java] [Python] Duplicate models generated when there are circular references between specs

[shylasrinivas]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
  Yes
• Have you validated the input using an OpenAPI validator (example)?
  Yes. Spec is valid.
• What's the version of OpenAPI Generator used?
  5.0.0 SNAPSHOT and 4.3.1
• Have you search for related issues/PRs?
  Duplicate classes / Models are generated if ( $ref) referenced externally. #2701
• What's the actual output vs expected output?
  Duplicate models with _2 suffix generated in go, 2 suffix in java. I have tested this in java and python and found the same issue.

Description

Models generated twice with same content when there are circular references between 2 specs
Issue occurs in Go, Java and Python languages.
Eg: model_complex_node_slice.go and model_complex_node_slice_2.go
ComplexNodeSlice.java and ComplexNodeSlice2.java

openapi-generator version

4.3.1 and 5.0.0 SNAPSHOT

OpenAPI declaration file content or url

https://gist.github.com/shylasrinivas/af9312c27f6c2a2d99d91c4c2c0323a1

Command line used for generation

openapi-generator generate -g go -i ~/testyamls/linked_list.yaml -o ~/testyamls/test

Related issues/PRs

#2701

Suggest a fix

Based on #2701 it seems the latest swagger parser should have fixed the issue. However, even with 5.0.0 SNAPSHOT version of openapi-generator which is using a newer swagger parser version (2.0.20) I am still seeing this issue. Any help is appreciated.

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[yangguangxiadeyun]

This may be the work-around for this case.
https://openapi-generator.tech/docs/usage/#type-mappings-and-import-mappings