[BUG] StackOverflowError in DefaultCodegen.addProperties when a schemas with same name are referenced directly and indirectly

[ivo500]

Bug Report Checklist

• [Y ] Have you provided a full/minimal spec to reproduce the issue?
• [ Y] Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used? 4.2.1
• [Y ] Have you search for related issues/PRs?
• What's the actual output vs expected output?
  java.lang.StackOverflowError, expected Sring generated project
• [Optional] Bounty to sponsor the fix (example)

Description

When trying to generate spring project from a complex .yaml file setup a java.lang.StackOverflowError is thrown.

The setup is the following:

Base.yaml contains a definition of Test
Blue.yaml contains a definition of Test which inherits with Allof from Base.yaml->Test
Green.yaml also contains a definition of Test which inherits with Allof from Base.yaml->Test and also it has a reference to Blue.yaml->Test

When generation is started for Green.yaml , DefaultCodegen.addProperties causes stack overflow.

Generator first loads the Base.yaml->Test reference in its cache.
The problem happens when the generator starts processing the Blue.yaml->Test reference in Green.yaml.
It loads the Blue.yaml->Test but wrongly overrides the Base.yaml->Test in its cache.
Blue.yaml->Test is inheriting from Base.yaml->Test but now after the override Blue.yaml->Test inherits from itself and becomes corrupt!!!!!!!!!.
After this when DefaultCodegen.addProperties starts its work it goes into endless recursion trying to process the corrupted self referencing Blue.yaml->Test .

See the stack trace below:

[main] INFO o.o.codegen.DefaultGenerator - OpenAPI Generator: spring (server)
[main] INFO o.o.codegen.DefaultGenerator - Generator 'spring' is considered stable.
[main] INFO o.o.codegen.languages.SpringCodegen - ----------------------------------
[main] INFO o.o.c.languages.AbstractJavaCodegen - Environment variable JAVA_POST_PROCESS_FILE not defined so the Java code may not be properly formatted. To define it, try 'export JAVA_POST_PROCESS_FILE="/usr/local/bin/clang-format -i"' (Linux/Mac)
[main] INFO o.o.c.languages.AbstractJavaCodegen - NOTE: To enable file post-processing, 'enablePostProcessFile' must be set to true (--enable-post-process-file for CLI).
[main] INFO o.o.c.languages.AbstractJavaCodegen - Processing operation test
[main] INFO o.o.c.languages.AbstractJavaCodegen - Processing operation inbox_storeTaskResponse
Exception in thread "main" java.lang.StackOverflowError
at org.apache.commons.lang3.StringUtils.isNotBlank(StringUtils.java:327)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2020)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2002)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2022)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2002)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2022)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2002)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2022)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2002)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2022)
at org.openapitools.codegen.DefaultCodegen.addProperties(DefaultCodegen.java:2002)

openapi-generator version

4.2.1

OpenAPI declaration file content or url

Command line used for generation

openapi-generator generate -i task-test.yaml -g spring -o test

Steps to reproduce

Related issues/PRs

Suggest a fix

The problem seem to be that when loading a second ref .yaml file which contains schemas with the same name as a component from the other first ref.yaml file. The second component overrides the first component.

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[emmaworley]

I am also running into this issue. Any workarounds?

[phirzel]

I added 3 suptypes extending this abstract class and I got the error below:
@Schema(name = "Place", description = "..",
type = "object",
title = "Abstract Place",
subTypes = {StopPlace.class, AddressPlace.class, PoiPlace.class})
public abstract class PlaceV3 implements Place {..}
@Schema(name = "StopPlace", description = "..")
@builder
@value
@tostring
public class StopPlace extends PlaceV3 {..}
..

Exception in thread "main" java.lang.StackOverflowError
at java.base/java.lang.String.lastIndexOf(String.java:1808)
at java.base/java.lang.String.lastIndexOf(String.java:1772)
at java.base/java.lang.String.lastIndexOf(String.java:1751)
at org.openapitools.codegen.utils.ModelUtils.getSimpleRef(ModelUtils.java:385)
at org.openapitools.codegen.utils.ModelUtils.getReferencedSchema(ModelUtils.java:832)
at org.openapitools.codegen.DefaultCodegen.recursiveGetDiscriminator(DefaultCodegen.java:2735)
at org.openapitools.codegen.DefaultCodegen.recursiveGetDiscriminator(DefaultCodegen.java:2750)

[kthoms]

I have faced the same issue now. Here is a minimal project where the issue can be reproduced when running mvn install: https://github.com/kthoms/issue-reproduction/tree/OpenAPITools/openapi-generator/recursive_properties

I would propose that addProperties should get an additional parameter with a set of already visited schemas. If properties for a known schema should be added (again), return.

[basinilya]

What a coincidence. The today's SNAPSHOT is failing for this command

openapi-generator-cli.bat generate -i https://datahub-spec.s3.eu-central-1.amazonaws.com/transform.yaml -g openapi

I'll wait for 20220219 and re-check

[basinilya]

Thanks @kthoms , your fork works