JavaClientCodegen: NullPointerException when using minimum/maximum

[ePaul]

Summary
When using the min or max constraint for a property, JavaClientCodegen.postProcessModelMaps throws an exception.

This happens with current master (also using current master of swagger-core).

Reproducible by

bug-trigger.yaml:

swagger: '2.0'
info:
  title: Swagger Codegen bug trigger
  description: |
     This demonstrates a bug in swagger-codegen.
  version: 0.0.1
basePath: /api
definitions:
  manual_discount:
    type: object
    properties:
      percent_value:
        type: number
        minimum: 0.0
        maximum: 100.0

command line (with debugger):

java -XX:-OmitStackTraceInFastThrow \
-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=8000 \
-jar /home/paulo/.m2/repository/io/swagger/swagger-codegen-cli/2.1.4-SNAPSHOT/swagger-codegen-cli-2.1.4-SNAPSHOT.jar \
generate -i src/main/resources/api/bug-trigger.yaml -l java \
-o target/generated-sources/swagger-codegen

This finishes without ouputting anything or writing any file.

Analysis
A breakpoint in DefaultGenerator.generate, line 322 shows a NullPointerException.

This exception is thrown in JavaClientCodegen.postProcessModels(), line 335: Here we try to iterate over a null list. That null list comes from allowableValues.get("values"), which for a string property could contain the values from an enum constraint. In this case, allowableValues is just a map with the min and max constraints.

Excepted behavior
This should generate a file for class ManualDiscount with a percentValue property.

Workaround
Don't use min or max.

[ePaul]

The code throwing the exception was added in #1126.
Adding another null-check here should be enough, I'll try to create a pull request for that.

[wing328]

PR merged