factory resolver misses volume component from devfile 2.0

[sleshchenko]

Describe the bug

Factory resolver misses volume component from devfile 2.0 with leads invalid devfile:

"message": "DevWorkspace.workspace.devfile.io "spring-petclinic" is invalid: [\u003cnil\u003e: Invalid value: "": "spec.template.components" must validate one and only one schema (oneOf). Found none valid, spec.template.components.container: Required value]",
Resolved devfile: mavenrepo component has only name.

{
  "v": "4.0",
  "devfile": {
    "schemaVersion": "2.0.0",
    "metadata": {
      "name": "spring-petclinic"
    },
    "components": [
      {
        "name": "maven",
        "container": {
          "image": "quay.io/eclipse/che-java8-maven:nightly",
          "volumeMounts": [
            {
              "name": "mavenrepo",
              "path": "/root/.m2"
            }
          ],
          "env": [
            {
              "name": "ENV_VAR",
              "value": "value"
            }
          ],
          "memoryLimit": "1536M"
        }
      },
      {
        "name": "mavenrepo"
      }
    ]
  }
}

Che version

• latest
• nightly
• other: please specify

Steps to reproduce

1. Deploy Che with devworkspace support enabled.
2. Accept factory from devfile with volume component, like $CHE_HOST#https://gist.githubusercontent.com/sleshchenko/e6382a45094b520118db2e5a318cc050/raw/b7d445c943c512092fea28206108d234aa761478/devfile2.yaml

Expected behavior

Che Server returns a valid devfile, which is a valid, so it's possible to create devworkspace from it.

Runtime

• kubernetes (include output of kubectl version)
• Openshift (include output of oc version)
• minikube (include output of minikube version and kubectl version)
• minishift (include output of minishift version and oc version)
• docker-desktop + K8S (include output of docker version and kubectl version)
• other: (please specify)

Screenshots

Installation method

• chectl
  • provide a full command that was used to deploy Eclipse Che (including the output)
  • provide an output of chectl version command
• OperatorHub
• I don't know

Environment

• my computer
  • Windows
  • Linux
  • macOS
• Cloud
  • Amazon
  • Azure
  • GCE
  • other (please specify)
• Dev Sandbox (workspaces.openshift.com)
• other: please specify

Eclipse Che Logs

Additional context

[mshaposhnik]

So since we didn't have model for Devfile v2, we serialize it as just a Map<String, Object> where inner objects are also Maps etc.
And due to this code, since legacy mode seems to be turned off,
the NullOrEmptyCollectionAdapter removes empty fields. cc @skabashnyuk @sparkoo any ideas how to fix ?

[sparkoo]

So when is this information lost? When parsing the devfile yaml into Map? Or when translating the Map into yaml content when creating the response for api call?

Is NullOrEmptyCollectionAdapter still relevant? Do we really need it?

What about parsing the devfile into JsonObject (or whatever is the class) instead of Map? Would it help? What about keep it as raw string and parse to Map only for validation?

[mshaposhnik]

when converting FactoryV2Dto into json type response.

[skabashnyuk]

At this point, we can't fix this issue for factory.resolve method without massive compatibility registration. Reason for that #13515 when we do not serialize maps for all DTO. alternative fo that 1. Do not add a component with empty content or sooner we are going to implement an alternative method to get content of the file Allow resolver API to resolve other files than [.]devfile.yaml #19540