OpenAPITools/openapi-generator · error · MojoExecutionException

Either 'addCompileSourceRoot' or 'addTestCompileSourceRoot'

Error message

Either 'addCompileSourceRoot' or 'addTestCompileSourceRoot' may be active, not both.

What it means

Thrown by addCompileSourceRootIfConfigured() in CodeGenMojo when both <addCompileSourceRoot> and <addTestCompileSourceRoot> are true. The plugin would otherwise add the same generated-sources root to both the main and test compile roots, causing duplicate classes, so it rejects the combination up front with a MojoExecutionException.

Source

Thrown at modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java:1225

            name = Files.getNameWithoutExtension(segments[segments.length - 1]);
        }

        return new File(output.getPath() + File.separatorChar + ".openapi-generator" + File.separatorChar + name + "-" + mojo.getExecutionId() + ".sha256");
    }

    private String getCompileSourceRoot() {
        final Object sourceFolderObject =
                configOptions == null ? null : configOptions
                        .get(CodegenConstants.SOURCE_FOLDER);
        final String sourceFolder = sourceFolderObject != null ? sourceFolderObject.toString() : "src/main/java";

        return output.getPath() + File.separatorChar + sourceFolder;
    }

    private void addCompileSourceRootIfConfigured() throws MojoExecutionException {
        if (addCompileSourceRoot) {
            if (addTestCompileSourceRoot) {
                throw new MojoExecutionException("Either 'addCompileSourceRoot' or 'addTestCompileSourceRoot' may be active, not both.");
            }
            project.addCompileSourceRoot(getCompileSourceRoot());
        } else if (addTestCompileSourceRoot) {
            project.addTestCompileSourceRoot(getCompileSourceRoot());
        }
    }

    /**
     * This method enables conversion of true/false strings in
     * config.additionalProperties (configuration/configOptions) to proper booleans.
     * This enables mustache files to handle the properties better.
     *
     * @param config
     */
    private void adjustAdditionalProperties(final CodegenConfig config) {
        Map<String, Object> configAdditionalProperties = config.additionalProperties();
        Set<String> keySet = configAdditionalProperties.keySet();
        for (String key : keySet) {

View on GitHub (pinned to fcec517be3)

Solutions

Keep exactly one flag true per execution: <addCompileSourceRoot>true</addCompileSourceRoot> for main sources, <addTestCompileSourceRoot>true</addTestCompileSourceRoot> for test sources.
If you need generated code in both main and test, define two executions with separate <output> directories and one flag each, then let test code depend on the main generated classes.
In inherited-config situations, override the unwanted flag to false in the child module.

Example fix

<!-- before -->
<configuration>
  <addCompileSourceRoot>true</addCompileSourceRoot>
  <addTestCompileSourceRoot>true</addTestCompileSourceRoot>
</configuration>

<!-- after -->
<configuration>
  <addCompileSourceRoot>true</addCompileSourceRoot>
  <addTestCompileSourceRoot>false</addTestCompileSourceRoot>
</configuration>

Defensive patterns

Strategy: validation

Validate before calling

# reject POMs that enable both source-root flags
grep -q '<addCompileSourceRoot>true' pom.xml && grep -q '<addTestCompileSourceRoot>true' pom.xml && {
  echo 'addCompileSourceRoot and addTestCompileSourceRoot are mutually exclusive'; exit 1;
}

Prevention

Model main vs test generation as two executions with separate output dirs and one flag each.
Set the unused flag explicitly to false when inheriting configuration from a parent POM.
Add a POM-lint rule for this pair — the failure only surfaces at build time, late in configuration review.

When it happens

Trigger: Generate goal configuration containing <addCompileSourceRoot>true</addCompileSourceRoot> and <addTestCompileSourceRoot>true</addTestCompileSourceRoot> simultaneously — commonly after copy-pasting test-generation config into main-generation config, or flipping a single boolean into two booleans during a refactor.

Common situations: One execution generating models for main code and another for tests, where someone enabled both flags in the shared configuration; inheriting plugin configuration from a parent POM that already sets one flag and adding the other in the child.

Related errors

AI-assisted analysis of OpenAPITools/openapi-generator@fcec517be3 (2026-08-22). Data as JSON: /api/errors/23ed261ff6c83c24. Report an issue: GitHub.