Exception in thread "main" java.lang.RuntimeException: missing swagger input or config!

Description

Doesn't work with local files

Swagger-codegen version

docker (latest)

Command line used for generation

docker run --rm -v ${PWD}:/local swaggerapi/swagger-codegen-cli generate \
    -i /local/output/full/openapi3.json \
    -l cwiki

Steps to reproduce

inside documentation:

run

docker run --rm -v ${PWD}:/local swaggerapi/swagger-codegen-cli generate \
    -i /local/output/full/openapi3.json \
    -l cwiki

[main] INFO io.swagger.parser.Swagger20Parser - reading from /local/output/full/openapi3.json
[main] INFO io.swagger.parser.Swagger20Parser - reading from /local/output/full/openapi3.json
[main] INFO io.swagger.codegen.ignore.CodegenIgnoreProcessor - No .swagger-codegen-ignore file found.
Exception in thread "main" java.lang.RuntimeException: missing swagger input or config!
        at io.swagger.codegen.DefaultGenerator.generate(DefaultGenerator.java:766)
        at io.swagger.codegen.cmd.Generate.run(Generate.java:299)
        at io.swagger.codegen.SwaggerCodegen.main(SwaggerCodegen.java:35)

When replace with url:

/local/output/full/openapi3.json with https://petstore.swagger.io/v2/swagger.json works fine

When path really invalid:

 docker run --rm -v ${PWD}:/local swaggerapi/swagger-codegen-cli generate \
    -i /local/output/full/adsf.json \     
    -l cwiki

[main] INFO io.swagger.parser.Swagger20Parser - reading from /local/output/full/adsf.json
[main] INFO io.swagger.parser.Swagger20Parser - reading from /local/output/full/adsf.json
[main] ERROR io.swagger.parser.SwaggerCompatConverter - failed to read resource listing
java.lang.RuntimeException: Could not find /local/output/full/adsf.json on the classpath
        at io.swagger.parser.util.ClasspathHelper.loadFileFromClasspath(ClasspathHelper.java:31)
        at io.swagger.parser.SwaggerCompatConverter.readResourceListing(SwaggerCompatConverter.java:207)
        at io.swagger.parser.SwaggerCompatConverter.read(SwaggerCompatConverter.java:123)
        at io.swagger.parser.SwaggerParser.read(SwaggerParser.java:96)
        at io.swagger.parser.SwaggerParser.read(SwaggerParser.java:66)
        at io.swagger.codegen.config.CodegenConfigurator.toClientOptInput(CodegenConfigurator.java:437)
        at io.swagger.codegen.cmd.Generate.run(Generate.java:297)
        at io.swagger.codegen.SwaggerCodegen.main(SwaggerCodegen.java:35)
[main] INFO io.swagger.codegen.ignore.CodegenIgnoreProcessor - No .swagger-codegen-ignore file found.
Exception in thread "main" java.lang.RuntimeException: missing swagger input or config!
        at io.swagger.codegen.DefaultGenerator.generate(DefaultGenerator.java:766)
        at io.swagger.codegen.cmd.Generate.run(Generate.java:299)
        at io.swagger.codegen.SwaggerCodegen.main(SwaggerCodegen.java:35)

Reproduce the Docker command using the local /local/output/full/openapi3.json input and compare it with the working URL case. Start at CodegenConfigurator.toClientOptInput and the DefaultGenerator.generate call shown in the stack trace. Done means a valid local file reaches cwiki generation without the “missing swagger input or config” exception.