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[Java]NullPointerException during codegen #12190

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harid opened this issue Jun 23, 2023 · 6 comments
Closed

[Java]NullPointerException during codegen #12190

harid opened this issue Jun 23, 2023 · 6 comments
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@micryc

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@harid
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harid commented Jun 23, 2023 •
edited

Getting NPE while generating codegen in Java. Stack trace attached below. YAML to repro the issue below.

Exception in thread "Thread-1" java.lang.NullPointerException
	at io.swagger.codegen.v3.generators.SchemaHandler.lambda$addInterfaces$1(SchemaHandler.java:196)
	at java.util.stream.MatchOps$1MatchSink.accept(MatchOps.java:90)
	at java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1361)
	at java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:126)
	at java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:499)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:486)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
	at java.util.stream.MatchOps$MatchOp.evaluateSequential(MatchOps.java:230)
	at java.util.stream.MatchOps$MatchOp.evaluateSequential(MatchOps.java:196)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.anyMatch(ReferencePipeline.java:449)
	at io.swagger.codegen.v3.generators.SchemaHandler.addInterfaces(SchemaHandler.java:196)
	at io.swagger.codegen.v3.generators.SchemaHandler.processComposedSchema(SchemaHandler.java:77)
	at io.swagger.codegen.v3.generators.SchemaHandler.processComposedSchemas(SchemaHandler.java:35)
	at io.swagger.codegen.v3.ISchemaHandler.readProcessedModels(ISchemaHandler.java:30)
	at io.swagger.codegen.v3.DefaultGenerator.generateModels(DefaultGenerator.java:391)
	at io.swagger.codegen.v3.DefaultGenerator.generate(DefaultGenerator.java:788)
	at io.swagger.codegen.v3.cli.cmd.Generate.run(Generate.java:388)
	at java.lang.Thread.run(Thread.java:750)

Swagger-codegen version 3.0.43

"/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java" -jar swagger-codegen-cli.jar generate -i ./restapi_orig.json -l java -o ./gen

Was able to generate a short YAML that repro'ed the issue:

openapi: 3.0.0
info:
  title: "reproCase"
  version: "0.1"
paths:
  /test:
    description: test
    post:
      responses:
        '200':
          description: OK
          content:
            applicaton/xml:
              schema:
                  oneOf:
                  - $ref: "#/components/responses/r-match"
                  - $ref: "#/components/schemas/nomatch"
components:
  responses:
    r-match:
      $ref: "#/components/schemas/match"
    r-nomatch:
      $ref: "#/components/schemas/nomatch"
  schemas:
    match:
      type: string
    nomatch:
      type: string

If I change the ref, "#/components/responses/r-match" to "#/components/schemas/match", it works(no NPE). It is probably wrong to refer to a component-ized response within an inline response but I wish it would error out without an NPE. I was originally trying to component-ize the responses but later decided to do the response inline. When I still had the mistaken reference to the component-ized response it threw this exception. But it took a lot of whittling down a long YAML to discover that.
@harid
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harid commented Jul 1, 2023

Updated with a YAML to repro.

@jeremydyoung
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I think I have a solution to this problem, but the code change belongs in https://github.com/swagger-api/swagger-codegen-generators

I think this yaml helps demonstrate the problem more clearly, because it does not require similarly named responses and schemas:

openapi: 3.0.0
info:
  title: "reproCase"
  version: "0.1"
paths:
  /test:
    post:
      description: test
      responses:
        '200':
          $ref: '#/components/responses/StandardOK'
components:
  responses:
    StandardOK:
      description: OK
      content:
        applicaton/xml:
          schema:
            $ref: '#/components/schemas/StandardResponse'
  schemas:
    StandardResponse:
      oneOf:
      - $ref: '#/components/schemas/schema1'
      - $ref: '#/components/schemas/schemaDoesNotExist'
    schema1:
      type: string
    schema2:
      type: string

Having something named nomatch in the example is misleading.

Using 3.0.46 I was able to reproduce:

Exception in thread "Thread-0" java.lang.NullPointerException: Cannot read field "classname" because "model" is null
	at io.swagger.codegen.v3.generators.SchemaHandler.lambda$addInterfaces$1(SchemaHandler.java:196)
	at java.base/java.util.stream.MatchOps$1MatchSink.accept(MatchOps.java:90)
	at java.base/java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1602)
	at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:129)
	at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:527)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:513)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.MatchOps$MatchOp.evaluateSequential(MatchOps.java:230)
	at java.base/java.util.stream.MatchOps$MatchOp.evaluateSequential(MatchOps.java:196)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.anyMatch(ReferencePipeline.java:632)
	at io.swagger.codegen.v3.generators.SchemaHandler.addInterfaces(SchemaHandler.java:196)
	at io.swagger.codegen.v3.generators.SchemaHandler.processComposedSchema(SchemaHandler.java:77)
	at io.swagger.codegen.v3.generators.SchemaHandler.processComposedSchemas(SchemaHandler.java:35)
	at io.swagger.codegen.v3.ISchemaHandler.readProcessedModels(ISchemaHandler.java:30)
	at io.swagger.codegen.v3.DefaultGenerator.generateModels(DefaultGenerator.java:391)
	at io.swagger.codegen.v3.DefaultGenerator.generate(DefaultGenerator.java:788)
	at io.swagger.codegen.v3.cli.cmd.Generate.run(Generate.java:388)
	at java.base/java.lang.Thread.run(Thread.java:833)

3.0.41 had a slightly different error:

Exception in thread "Thread-1" java.lang.NullPointerException
	at io.swagger.codegen.v3.generators.SchemaHandler.lambda$addInterfaces$1(SchemaHandler.java:196)
	at java.util.stream.MatchOps$1MatchSink.accept(MatchOps.java:90)
	at java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1361)
	at java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:126)
	at java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:499)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:486)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
	at java.util.stream.MatchOps$MatchOp.evaluateSequential(MatchOps.java:230)
	at java.util.stream.MatchOps$MatchOp.evaluateSequential(MatchOps.java:196)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.anyMatch(ReferencePipeline.java:516)
	at io.swagger.codegen.v3.generators.SchemaHandler.addInterfaces(SchemaHandler.java:196)
	at io.swagger.codegen.v3.generators.SchemaHandler.processComposedSchema(SchemaHandler.java:77)
	at io.swagger.codegen.v3.generators.SchemaHandler.processComposedSchemas(SchemaHandler.java:35)
	at io.swagger.codegen.v3.ISchemaHandler.readProcessedModels(ISchemaHandler.java:30)
	at io.swagger.codegen.v3.DefaultGenerator.generateModels(DefaultGenerator.java:391)
	at io.swagger.codegen.v3.DefaultGenerator.generate(DefaultGenerator.java:788)
	at io.swagger.codegen.v3.cli.cmd.Generate.run(Generate.java:388)
	at java.lang.Thread.run(Thread.java:750)

With my changes we get a sane error message:

12:54:35.186 [Thread-0] ERROR i.s.c.v3.generators.SchemaHandler - Could not find model for reference '#/components/schemas/schemaDoesNotExist' when processing 'StandardResponse' with json - {
  "oneOf" : [ {
    "$ref" : "#/components/schemas/schema1"
  }, {
    "$ref" : "#/components/schemas/schemaDoesNotExist"
  } ]
}

PR incoming

@jeremydyoung jeremydyoung mentioned this issue Jul 28, 2023
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@harid
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harid commented Jul 28, 2023

Thanks for looking into this. "match" and "nomatch" are more common in the Voice Recognition domain I work on.

One thing I want to point out: in my example YAML, all schemas exist. It is just referencing the response from "components" in the actual response definition caused the issue. Not sure if your example uncovered a new issue or if it covers the one highlighted by my example as well.

@jeremydyoung
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jeremydyoung commented Jul 28, 2023 •
edited

Unfortunately, you are mixing up responses and schemas in your situation. Just because a response exists with a particular name does not mean that a schema exists with a particular name.

When using my updated code, you see the actual error:

15:01:16.194 [Thread-0] ERROR i.s.c.v3.generators.SchemaHandler - Could not find model for reference '#/components/responses/r-match' when processing 'inline_response_200' with json - {
  "oneOf" : [ {
    "$ref" : "#/components/responses/r-match"
  }, {
    "$ref" : "#/components/schemas/nomatch"
  } ]
}

The problem is that there is no SCHEMA with the name #/components/responses/r-match because that's the name of a response.

@harid
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harid commented Jul 28, 2023

Ok, good. Looks like the fix produces a better error for my case as well.

Yes, as I admitted in my original description, referencing a response from "components" in the inline response was a mistake but few things led to that:

It is probably wrong to refer to a component-ized response within an inline response but I wish it would error out without an NPE. I was originally trying to component-ize the responses but later decided to do the response inline. When I still had the mistaken reference to the component-ized response it threw this exception. But it took a lot of whittling down a long YAML to discover that.

The request was to get a better error response which your fix does provide, it appears.

@micryc micryc self-assigned this Apr 29, 2024
@micryc micryc closed this as completed Apr 29, 2024
@micryc micryc reopened this Apr 30, 2024
@micryc micryc mentioned this issue Apr 30, 2024
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@micryc
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micryc commented Apr 30, 2024

Handled by swagger-api/swagger-codegen-generators#1274

@micryc micryc closed this as completed Apr 30, 2024
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