Missing model types cause a NullPointerException

[bedag-moo]

If a parameter type refers to a missing model:

"operations" : [ {
  "method" : "POST",
  "nickname" : "updateIssue",
  "type" : "Issue",
  "parameters" : [ {
    "type" : "UUID",
    "paramType" : "path",
    "name" : "id",
    "required" : true
  }, {
    "type" : "IssueEditCommand",
    "paramType" : "body",
    "name" : "issue",
    "required" : true
  } ],
  "summary" : "Updates an existing issue."
} ]

Code generation fails with a NullPointerException:

java.lang.NullPointerException
        at io.swagger.models.properties.RefProperty.get$ref(RefProperty.java:53)
        at io.swagger.codegen.DefaultCodegen.getSwaggerType(DefaultCodegen.java:470)
        at io.swagger.codegen.languages.JavaClientCodegen.getSwaggerType(JavaClientCodegen.java:280)
        at io.swagger.codegen.DefaultCodegen.fromProperty(DefaultCodegen.java:626)
        at io.swagger.codegen.DefaultCodegen.fromParameter(DefaultCodegen.java:1051)
        at io.swagger.codegen.DefaultCodegen.fromOperation(DefaultCodegen.java:880)
        at ch.bedag.eng.various.rcg.SimpleJavaClientCodegen.fromOperation(SimpleJavaClientCodegen.java:29)
        at io.swagger.codegen.DefaultGenerator.processOperation(DefaultGenerator.java:448)
        at io.swagger.codegen.DefaultGenerator.processPaths(DefaultGenerator.java:401)
        at io.swagger.codegen.DefaultGenerator.generate(DefaultGenerator.java:170)

Ideally, the exception message would identify the problematic operation, so we don't have to debug the maven plugin to find out where the swagger documentation is incomplete.

[bedag-moo]

Fixing #1266 has somewhat improved matters, but the stack trace is not very readable, and does not identify the missing model:

[ERROR] Error while trying to get Config from Operation for tag(issue)
        Resource: post /issue/{id}/status
        Operation:io.swagger.models.Operation@41b7cbf6
        Definitions: {Ref=io.swagger.models.ModelImpl@1ce79d8c, IssueTransitionCommand=io.swagger.models.ModelImpl@9cc58
885, User=io.swagger.models.ModelImpl@6b4dd805, Issue=io.swagger.models.ModelImpl@23a6b440, TechId=io.swagger.models.Mod
elImpl@a45b3e6e, IssueEditCommand=io.swagger.models.ModelImpl@529c85bf, Label=io.swagger.models.ModelImpl@a2ecc544, Pers
on=io.swagger.models.ModelImpl@e74ab578}

java.lang.NullPointerException
        at io.swagger.models.properties.RefProperty.get$ref(RefProperty.java:52)
        at io.swagger.codegen.DefaultCodegen.getSwaggerType(DefaultCodegen.java:487)
        at io.swagger.codegen.languages.JavaClientCodegen.getSwaggerType(JavaClientCodegen.java:300)
        at io.swagger.codegen.DefaultCodegen.fromProperty(DefaultCodegen.java:646)
        at io.swagger.codegen.DefaultCodegen.fromParameter(DefaultCodegen.java:1185)
        at io.swagger.codegen.DefaultCodegen.fromOperation(DefaultCodegen.java:999)
        at ch.bedag.eng.various.rcg.SimpleJavaClientCodegen.fromOperation(SimpleJavaClientCodegen.java:29)
        at io.swagger.codegen.DefaultGenerator.processOperation(DefaultGenerator.java:470)
        at io.swagger.codegen.DefaultGenerator.processPaths(DefaultGenerator.java:418)
        at io.swagger.codegen.DefaultGenerator.generate(DefaultGenerator.java:184)
        at ch.bedag.eng.various.rcg.RestClientGeneratorMojo.execute(RestClientGeneratorMojo.java:62)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
        at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.
java:51)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:862)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:286)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:197)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:483)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)

[bedag-moo]

I don't understand swagger-model well enough to extract the name of the missing model myself.

[wing328]

@bedag-moo thanks for the detailed error messages. I tried repeating the issue by removing schema from https://github.com/swagger-api/swagger-codegen/blob/master/modules/swagger-codegen/src/test/resources/2_0/petstore.json#L44 (so that the body parameter refers to a missing model) but in vain.

Am I repeating the issue in the right way?

[bedag-moo]

@wing328: No :-)

Here is the full spec for my testcase:

{
  "apiVersion" : "1",
  "swaggerVersion" : "1.2",
  "basePath" : "/api",
  "resourcePath" : "/issue",
  "apis" : [ {
    "path" : "/issue",
    "operations" : [ {
      "method" : "POST",
      "nickname" : "createIssue",
      "type" : "Issue",
      "parameters" : [ {
        "type" : "IssueEditCommand",
        "paramType" : "body",
        "name" : "dto",
        "required" : true
      } ],
      "summary" : "Creates a new issue, and returns it."
    } ]
  }, {
    "path" : "/issue/assignedToMe",
    "operations" : [ {
      "method" : "GET",
      "nickname" : "getAssignedToMe",
      "type" : "array",
      "items" : {
        "$ref" : "Issue"
      },
      "summary" : "Returns a list of issues assigned to the current user."
    } ]
  }, {
    "path" : "/issue/reportedByMe",
    "operations" : [ {
      "method" : "GET",
      "nickname" : "getReportedByMe",
      "type" : "array",
      "items" : {
        "$ref" : "Issue"
      },
      "summary" : "Returns a list of issues reported by the current user."
    } ]
  }, {
    "path" : "/issue/{id}",
    "operations" : [ {
      "method" : "POST",
      "nickname" : "updateIssue",
      "type" : "Issue",
      "parameters" : [ {
        "type" : "TechId",
        "paramType" : "path",
        "name" : "id",
        "required" : true
      }, {
        "type" : "IssueEditCommand",
        "paramType" : "body",
        "name" : "dto",
        "required" : true
      } ],
      "summary" : "Updates an existing issue."
    } ]
  }, {
    "path" : "/issue/{id}/status",
    "operations" : [ {
      "method" : "POST",
      "nickname" : "perform",
      "type" : "Issue",
      "parameters" : [ {
        "type" : "TechId",
        "paramType" : "path",
        "name" : "id",
        "required" : true
      }, {
        "type" : "IssueTransitionCommand",
        "paramType" : "body",
        "name" : "cmd",
        "required" : true
      } ],
      "summary" : "Performs the given transition."
    } ]
  } ],
  "models" : {
    "Ref" : {
      "id" : "Ref",
      "properties" : {
        "id" : {
          "type" : "TechId"
        }
      }
    },
    "IssueTransitionCommand" : {
      "id" : "IssueTransitionCommand",
      "properties" : {
        "issueId" : {
          "type" : "TechId"
        },
        "transition" : {
          "type" : "string",
          "enum" : [ "startProgress", "stopProgress", "resolve", "reopen", "close" ]
        }
      }
    },
    "Issue" : {
      "id" : "Issue",
      "properties" : {
        "id" : {
          "type" : "TechId"
        },
        "version" : {
          "type" : "integer",
          "format" : "int64"
        },
        "reporter" : {
          "type" : "User"
        },
        "assignee" : {
          "type" : "User"
        },
        "subject" : {
          "type" : "string"
        },
        "description" : {
          "type" : "string"
        },
        "status" : {
          "type" : "string",
          "enum" : [ "open", "inProgress", "resolved", "closed" ]
        },
        "labels" : {
          "type" : "array",
          "items" : {
            "$ref" : "Label"
          }
        },
        "availableTransitions" : {
          "type" : "array",
          "items" : {
            "type" : "string",
            "enum" : [ "startProgress", "stopProgress", "resolve", "reopen", "close" ]
          }
        }
      }
    },
    "User" : {
      "id" : "User",
      "properties" : {
        "id" : {
          "type" : "TechId"
        },
        "version" : {
          "type" : "integer",
          "format" : "int64"
        },
        "openId" : {
          "type" : "string"
        },
        "fullName" : {
          "type" : "string"
        },
        "role" : {
          "type" : "string",
          "enum" : [ "system", "admin", "developer", "user" ]
        }
      },
      "required" : [ "openId", "fullName", "role" ]
    },
    "TechId" : {
      "id" : "TechId",
      "properties" : {
        "uuid" : {
          "type" : "UUID"
        }
      }
    },
    "IssueEditCommand" : {
      "id" : "IssueEditCommand",
      "properties" : {
        "id" : {
          "type" : "TechId"
        },
        "version" : {
          "type" : "integer",
          "format" : "int64"
        },
        "subject" : {
          "type" : "string"
        },
        "description" : {
          "type" : "string"
        },
        "assignee" : {
          "type" : "Ref"
        }
      }
    },
    "Label" : {
      "id" : "Label",
      "properties" : {
        "id" : {
          "type" : "TechId"
        },
        "version" : {
          "type" : "integer",
          "format" : "int64"
        },
        "name" : {
          "type" : "string"
        }
      }
    }
  }
}

The type UUID has no entry under "model".

[wing328]

@bedag-moo ok. I'll give it a try tomorrow and fix the NPE in a branch that I'm working on.

[wing328]

@bedag-moo I noticed that some "path" parameters have the type "TechId". Replacing it with "string" can workaround the issue before we put in place better handling of the NPE.

For path parameters, I don't think we should use model, which can have more than 1 property and currently there's no way for codegen (or other tool) to figure out which property to substitute the path parameter (e.g. {id}).

[bedag-moo]

I agree about path parameters, and have since changed their type to string.

Still, a more descriptive exception would be nice.

[wing328]

PR merged.