[BUG][dart-dio] fails with Null context for variable '.' on line 29

[vladaman]

Description

When using dart-dio generator I get following exception. Regular dart generator works fine. Looks like it's related to allOf block but I can't pinpoint where exactly.

Exception in thread "main" java.lang.RuntimeException: Could not generate model 'CardWidget'
	at org.openapitools.codegen.DefaultGenerator.generateModels(DefaultGenerator.java:544)
	at org.openapitools.codegen.DefaultGenerator.generate(DefaultGenerator.java:875)
	at org.openapitools.codegen.cmd.Generate.execute(Generate.java:440)
	at org.openapitools.codegen.cmd.OpenApiGeneratorCommand.run(OpenApiGeneratorCommand.java:32)
	at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:66)
Caused by: java.lang.NullPointerException: Null context for variable '.' on line 29
	at com.samskivert.mustache.Template.getValueIn(Template.java:288)
	at com.samskivert.mustache.Template.getValue(Template.java:224)
	at com.samskivert.mustache.Template.getValueOrDefault(Template.java:279)
	at com.samskivert.mustache.Mustache$VariableSegment.execute(Mustache.java:802)
	at com.samskivert.mustache.Mustache$BlockSegment.executeSegs(Mustache.java:845)
	at com.samskivert.mustache.Mustache$SectionSegment.execute(Mustache.java:866)
	at com.samskivert.mustache.Mustache$BlockSegment.executeSegs(Mustache.java:845)
	at com.samskivert.mustache.Mustache$InvertedSegment.execute(Mustache.java:906)
	at com.samskivert.mustache.Mustache$BlockSegment.executeSegs(Mustache.java:845)
	at com.samskivert.mustache.Mustache$SectionSegment.execute(Mustache.java:881)
	at com.samskivert.mustache.Mustache$BlockSegment.executeSegs(Mustache.java:845)
	at com.samskivert.mustache.Mustache$SectionSegment.execute(Mustache.java:866)
	at com.samskivert.mustache.Template.executeSegs(Template.java:157)
	at com.samskivert.mustache.Mustache$IncludedTemplateSegment.execute(Mustache.java:774)
	at com.samskivert.mustache.Mustache$BlockSegment.executeSegs(Mustache.java:845)
	at com.samskivert.mustache.Mustache$InvertedSegment.execute(Mustache.java:910)
	at com.samskivert.mustache.Mustache$BlockSegment.executeSegs(Mustache.java:845)
	at com.samskivert.mustache.Mustache$SectionSegment.execute(Mustache.java:881)
	at com.samskivert.mustache.Mustache$BlockSegment.executeSegs(Mustache.java:845)
	at com.samskivert.mustache.Mustache$SectionSegment.execute(Mustache.java:866)
	at com.samskivert.mustache.Template.executeSegs(Template.java:157)
	at com.samskivert.mustache.Template.execute(Template.java:134)
	at com.samskivert.mustache.Template.execute(Template.java:125)
	at org.openapitools.codegen.templating.MustacheEngineAdapter.compileTemplate(MustacheEngineAdapter.java:65)
	at org.openapitools.codegen.TemplateManager.write(TemplateManager.java:163)
	at org.openapitools.codegen.DefaultGenerator.processTemplateToFile(DefaultGenerator.java:1017)
	at org.openapitools.codegen.DefaultGenerator.generateModel(DefaultGenerator.java:382)
	at org.openapitools.codegen.DefaultGenerator.generateModels(DefaultGenerator.java:535)

OpenAPI declaration file content or url

    AppResponse:
      type: object
      description: "View Objects"
      properties:
        popup:
          $ref: '#/components/schemas/CardWidget'
        widgets:
          type: array
          items:
            anyOf:
            - $ref: '#/components/schemas/CardWidget'
            - $ref: '#/components/schemas/TextWidget'
          discriminator:
            propertyName: objtype
    ClickableWidget:
      properties:
        style:
          type: object
          properties:
            bold:
              type: boolean
              default: false
    CardWidget:
      type: object
      description: "Card View Widget"
      allOf:
        - $ref: '#/components/schemas/ClickableWidget'
      properties:
        image_urL:
          type: string
       objtype:
          type: string
          enum: [SOMETYPE]

openapi-generator version

openapi-generator-cli 5.1.0
  commit : e023eaa
  built  : 2021-03-20T09:18:49Z
  source : https://github.com/openapitools/openapi-generator
  docs   : https://openapi-generator.tech/

Might be related to #8860 (comment)

[kuhnroyal]

Hmm, not sure, you can try the dart-dio-next generator but I don't think it will change anything.
AllOF/AnyOF is not currently supported in a meaningful way.

[kuhnroyal]

Can not reproduce the error on master with neither dart-dio or dart-dio-next.
The generated code is not working but it is being generated.
Do you have custom templates by any chance?

[kuhnroyal]

@vladaman Any new insights on your side?

[jmartin127]

I am experiencing the same issue. So far, I have seen the issue within the allOf field:

      allOf:
      - $ref: '#/components/schemas/AccountBase'

As well as some of the non-standard fields. I'll see if I can get a smaller example together, but in the meantime:

Here is a Docker command the reproduces the issue against the Plaid Open API spec:

% docker run --rm -v "${PWD}:/local" openapitools/openapi-generator-cli:v6.0.0 generate \
    -i https://raw.githubusercontent.com/plaid/plaid-openapi/master/2020-09-14.yml \
    -g dart-dio \
    -o /local/out/dart

The only thing I am seeing so far that all of these failures have in common is a $ref entry:

$ref: '#/components/schemas/...'

[jmartin127]

UPDATE: In my case, the cause of this was that the referenced components had an enumeration with a null value. For example:

      enum:
      - EMPLOYMENT_STATUS_ACTIVE
      - EMPLOYMENT_STATUS_INACTIVE
      - null

This issue may be caused by: #11625

[kuhnroyal]

% docker run --rm -v "${PWD}:/local" openapitools/openapi-generator-cli:v6.0.0 generate \
    -i https://raw.githubusercontent.com/plaid/plaid-openapi/master/2020-09-14.yml \
    -g dart-dio \
    -o /local/out/dart

I can generate that with the current master, the Dart code does not fully compile but the OpenAPI generator does not throw.
@wing328 It seems the issue can be closed.

[kuhnroyal]

This was likely fixed by the jmustache update to 1.15 - see samskivert/jmustache#96