[BUG] NullPointerException when loading configuration

[idkCpp]

Description

I have an automatic build pipeline that uses the openapi generator to create a python-flask server.
Today the builds started failing with a NullPointerException and the below mentioned stack-trace.

openapi-generator version

I use the following Docker Image:
openapitools/openapi-generator-cli latest 132da9168d58

OpenAPI declaration file content or url

Seems to be irrelevant, also happens with the swagger petstore.

Generation Details

docker run --rm -u $(id -u) -v "$(pwd):/local" openapitools/openapi-generator-cli generate -i /local/openapi.yaml -g python-flask -o /local/app -c /local/config.json --package-name PKGNAM --skip-operation-example

Contents of config.json:

{
        "packageName": "PKGNAM",
        "serverPort": "8080"
}

Output

Exception in thread "main" java.lang.NullPointerException
	at java.base/java.lang.String.concat(Unknown Source)
	at org.openapitools.codegen.CodegenConfigLoader.forName(CodegenConfigLoader.java:48)
	at org.openapitools.codegen.config.CodegenConfigurator.fromFile(CodegenConfigurator.java:94)
	at org.openapitools.codegen.cmd.Generate.execute(Generate.java:272)
	at org.openapitools.codegen.cmd.OpenApiGeneratorCommand.run(OpenApiGeneratorCommand.java:32)
	at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:66)

[JLEdward]

Also starting to get this NullPointerException from yesterday. Strangely I do not see any version changes on the openapi-generator-cli.jar:

$ java -jar /opt/openapi-generator/modules/openapi-generator-cli/target/openapi-generator-cli.jar version
5.4.0-SNAPSHOT

Anyone aware of any solution to this please? For now I'm reverting to 5.3.1.

[willgit-sl]

Also starting to get this NullPointerException from yesterday. Strangely I do not see any version changes on the openapi-generator-cli.jar:

$ java -jar /opt/openapi-generator/modules/openapi-generator-cli/target/openapi-generator-cli.jar version
5.4.0-SNAPSHOT

Anyone aware of any solution to this please? For now I'm reverting to 5.3.1.

I'm seeing the same issue. Didn't have to go back to 5.3.1, I just went back to commit 361b593

[provokateurin]

Hello, I'm also facing this issue and did a bisect and found out that commit dd3bba8 broke it. @spacether pinging you as the author of the commit.

[LPCmedia]

This is rather blocker for us. Can we revert or is there something we need to add to the config file ?

[idkCpp]

I now use openapitools/openapi-generator-cli:latest-release instead of openapitools/openapi-generator-cli:latest. For me this works fine.

[spacether]

Thank you for reporting this. I am investigating it.
Short term solutions are to use our latest release or to add the generator name into your config file. If I can't come up with a quick fix then I will revert it.

[spacether]

Sorry for creating this bug in master branch.
The master branch has been fixed by #11316
Separately I will work on a new PR to add the feature back in and I will include a test which covers this use case of:

• g (generatorName) passed in to command line args
• generatorName not present in the config file