swagger-api/swagger-codegen

NPE for parameter without a name

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#3,708 opened on Sep 2, 2016

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Issue: BugIssue: Invalid spechelp wanted

Description

Description

Codegen throws a NPE when generating code for a buggy declaration that has parameters without a name. Happens at least with nodejs-server and python-flask, but not with any client codegens I've tried, so maybe this is a server-only issue?

Swagger-codegen version

Current master

Swagger declaration file content or url
swagger: "2.0"
paths:
  /:
    get:
      operationId: foo
      parameters:
        - bug-here:
          in: query
          type: string
Steps to reproduce
$ java -jar swagger-codegen-cli.jar generate -i bug.yml -l nodejs-server
[main] INFO io.swagger.parser.Swagger20Parser - reading from bug.yml
[main] INFO io.swagger.codegen.ignore.CodegenIgnoreProcessor - No .swagger-codegen-ignore file found.
Exception in thread "main" java.lang.RuntimeException: Could not process operation:
  Tag: default
  Operation: foo
  Resource: get /
  Definitions: {}
  Exception: null
    at io.swagger.codegen.DefaultGenerator.processOperation(DefaultGenerator.java:808)
    at io.swagger.codegen.DefaultGenerator.processPaths(DefaultGenerator.java:700)
    at io.swagger.codegen.DefaultGenerator.generate(DefaultGenerator.java:377)
    at io.swagger.codegen.cmd.Generate.run(Generate.java:223)
    at io.swagger.codegen.SwaggerCodegen.main(SwaggerCodegen.java:36)
Caused by: java.lang.NullPointerException
    at java.util.regex.Matcher.getTextLength(Matcher.java:1283)
    at java.util.regex.Matcher.reset(Matcher.java:309)
    at java.util.regex.Matcher.<init>(Matcher.java:229)
    at java.util.regex.Pattern.matcher(Pattern.java:1093)
    at io.swagger.codegen.DefaultCodegen.camelize(DefaultCodegen.java:2875)
    at io.swagger.codegen.DefaultCodegen.fromProperty(DefaultCodegen.java:1385)
    at io.swagger.codegen.DefaultCodegen.fromParameter(DefaultCodegen.java:2227)
    at io.swagger.codegen.DefaultCodegen.fromOperation(DefaultCodegen.java:1993)
    at io.swagger.codegen.DefaultGenerator.processOperation(DefaultGenerator.java:756)
    ... 4 more
Suggest a Fix

Should probably ignore parameters without a name, and output a warning message about them (along with input filename, linenumber if possible). Or fail with a descriptive message.

Contributor guide

Tech stack
java
Domain
toolingbackend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Javaunderstanding of swagger codegen
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
The issue is caused by a NullPointerException in DefaultCodegen.camelize when a parameter has no name. The fix should be in DefaultCodegen.fromParameter or fromProperty to handle parameters without a name gracefully. Look at the stack trace: the error occurs at DefaultCodegen.java line 2875 (camelize) and 1385 (fromProperty). One approach is to check if the parameter name is null and skip the parameter with a warning. The linked issue suggests ignoring parameters without a name and outputting a warning message. Explore the code around those lines and implement a null check.