[JAVA] Nested generics causes missing imports

[markebbers]

Description

If a method is using nested generics in an method argument, like List<List>, the generated Api class is missing an import for this model class. In this case 'MissingObject'.

Swagger-codegen version

Tested with 2.2.1 and 2.2.2.

Swagger declaration file content or url

proof of concept:
https://gist.github.com/markebbers/7e9fcecdfe1b5c15604618519b5a5ecc

suspect:

"parameters": [
          {
            "in": "body",
            "name": "body",
            "description": "",
            "required": false,
            "schema": {
              "type": "array",
              "items": {
                "type": "array",
                "items": {
                  "$ref": "#/definitions/MissingObject"
                }
              }
            }
          }
        ]

Command line used for generation

Used the swagger-codegen-maven-plugin 2.2.1 and 2.2.2.

[DEBUG] Configuring mojo 'io.swagger:swagger-codegen-maven-plugin:2.2.2:generate' with basic configurator -->
[DEBUG]   (f) addCompileSourceRoot = true
[DEBUG]   (f) apiPackage = poc.api
[DEBUG]   (f) configOptions = {dateLibrary=joda, library=jersey2}
[DEBUG]   (f) inputSpec = /home/x/Work/prototype/pocswaggergeneric/src/main/resources/swagger.json
[DEBUG]   (f) language = java
[DEBUG]   (f) modelPackage = poc.model
[DEBUG]   (f) output = /home/x/Work/prototype/pocswaggergeneric/target/generated-sources/openapi
[DEBUG]   (f) project = MavenProject: poc:api:1.0-SNAPSHOT @ /home/x/Work/prototype/pocswaggergeneric/pom.xml
[DEBUG]   (f) verbose = false
[DEBUG] -- end configuration --
[INFO] reading from /home/x/Work/prototype/pocswaggergeneric/src/main/resources/swagger.json

Steps to reproduce

Generate and compile the code.

Related issues

Suggest a Fix

Not yet found. But it looks likes the nested array of arrays of ObjectMissing objects is the cause of the problem.

[wing328]

@markebbers thanks for reporting the issue with a spec to easily reproduce the issue, which helps a lot.

I'm looking into it...

[wing328]

It should be fixed by #5891

I did a test with the spec you provided and mvn test does not report any issue.

[wing328]

@markebbers PR merged into master. Please pull the latest master to give it a try.