Golang client can use pattern-based discriminator between oneOf

[maxlapshin]

Golang cannot read oneOf without clear discriminator, because it doesn't do validation and cannot choose between different options.

This is why I had to change decoding of oneOf from just parsing JSON to parsing + validating to select, which of oneOf options is ok. Sorry, but it seems to be the only correct way to work with oneOf

This PR works for me, but I suppose that I need to enhance it.

My example is in modules/openapi-generator/src/test/resources/3_0/go/oneof-with-pattern-discriminator.yaml

Maybe I need to put it to bin/configs?

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• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh ./bin/configs/*.yaml
  ./bin/utils/export_docs_generators.sh
  

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[wing328]

can you please review the test failure when you've time?

https://app.circleci.com/pipelines/github/OpenAPITools/openapi-generator/29686/workflows/833af623-22a8-484c-bfef-f9722fc69760/jobs/95810

[maxlapshin]

Would you kindly give a hint, how can I launch only particular in my cloned repo?

[wing328]

to run the tests locally, please run mvn integration-test -f samples/openapi3/client/petstore/go/pom.xml

you will need to run a petstore server locally: https://github.com/OpenAPITools/openapi-generator/wiki/Integration-Tests#how-to-add-integration-tests-for-new-petstore-samples

[maxlapshin]

@wing328 thanks for the hints. I've checked, found my bug and updated PR. Seems that tests are passing now.

[wing328]

looks good. let's give it a try

thanks for the PR

[wing328]

FYI. I've merged #19358 to improve the handling of backtick in the pattern (regex).

Please give it a try with the latest snapshot version (https://oss.sonatype.org/content/repositories/snapshots/org/openapitools/openapi-generator-cli/7.8.0-SNAPSHOT/) and let us know if you spot any issue.