Openapi-generator: [BUG][Java][spring][maven] FileNotFoundException when spec file is present in another jar

[ashuto-sh]

Description

When using openapi-generator-maven-plugin to generate sources with a yaml spec present in another jar, the models and other operation files are generated successfully but towards the end FileNotFoundException is thrown. Probably this might be due to classloader.

openapi-generator version

4.0.0-beta

Pom file configuration

...
      <plugin>
        <groupId>org.openapitools</groupId>
        <artifactId>openapi-generator-maven-plugin</artifactId>
        <version>4.0.0-beta</version>

        <executions>
          <execution>
            <goals>
              <goal>generate</goal>
            </goals>
            <configuration>
              <inputSpec>/openapi.yaml</inputSpec>
              <language>spring</language>
              <library>spring-mvc</library>
              <configOptions>                
                <useTags>false</useTags>
                <invokerPackage>${project.groupId}.backend.generated.server</invokerPackage>
                <apiPackage>${project.groupId}.backend.generated.server.api</apiPackage>
                <modelPackage>${project.groupId}.backend.generated.server.model</modelPackage>
              </configOptions>             
              <modelNameSuffix>Model</modelNameSuffix>
            </configuration>
          </execution>
        </executions>

        <dependencies>
          <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>${swagger.spec.artifactId}</artifactId>
            <version>${swagger.spec.version}</version>
          </dependency>
        </dependencies>
      </plugin>
...

Suggest a fix

Probable solution would be to use something similar to

this.getClass().getClassLoader().getResourceAsStream(inputSpec)

instead of

File inputSpecFile = new File(inputSpec);

at following line

https://github.com/OpenAPITools/openapi-generator/blob/9334dd391ac15fb38c469e8b206f35ee4d84d440/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java#L359

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[Woodham]

I think the same line of code is breaking remote inputSpecs? If the inputSpec is a URL then it also breaks with a FileNotFoundException (naturally because a url isn't a file).

[Catscratch]

Same here. It would also be nice to use an external server address as inputSpec, like WSDL stub generation works.

E.g.
<inputSpec>https://petstore.swagger.io/v2/swagger.json</inputSpec>

[wing328]

Please give it another try as #3440 has been merged into master