{"record":{"id":"0e9725907c6cd87d","repo":"apple/pkl","slug":"no-stack-frame-transformer-set","errorCode":null,"errorMessage":"No stack frame transformer set.","messagePattern":"No stack frame transformer set\\.","errorType":"validation","errorClass":"IllegalStateException","httpStatus":null,"severity":"error","filePath":"pkl-core/src/main/java/org/pkl/core/EvaluatorBuilder.java","lineNumber":579,"sourceCode":"        httpClientBuilder.setHeaders(settings.http().headers());\n      }\n      setHttpClient(httpClientBuilder.buildLazily());\n    }\n\n    if (settings.traceMode() != null) {\n      setTraceMode(settings.traceMode());\n    }\n\n    return this;\n  }\n\n  public Evaluator build() {\n    if (securityManager == null) {\n      securityManager = securityManagerBuilder.build();\n    }\n\n    if (stackFrameTransformer == null) {\n      throw new IllegalStateException(\"No stack frame transformer set.\");\n    }\n\n    return new EvaluatorImpl(\n        stackFrameTransformer,\n        color,\n        securityManager,\n        httpClient,\n        new LoggerImpl(logger, stackFrameTransformer),\n        // copy to shield against subsequent modification through builder\n        new ArrayList<>(moduleKeyFactories),\n        new ArrayList<>(resourceReaders),\n        new HashMap<>(environmentVariables),\n        new HashMap<>(externalProperties),\n        timeout,\n        moduleCacheDir,\n        dependencies,\n        outputFormat,\n        traceMode,","sourceCodeStart":561,"sourceCodeEnd":597,"githubUrl":"https://github.com/apple/pkl/blob/f3efcbfc9b60d30053b0536d664948d7aa1b8673/pkl-core/src/main/java/org/pkl/core/EvaluatorBuilder.java#L561-L597","documentation":"EvaluatorImpl.build() requires a stack frame transformer: if setStackFrameTransformer was never called, the field is null and building an Evaluator is impossible. It is a mandatory setup step, not an optional customization, so the builder fails fast rather than producing an evaluator with default frame handling.","triggerScenarios":"Thrown at pkl-core/src/main/java/org/pkl/core/EvaluatorBuilder.java:579 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Call setStackFrameTransformer(...) with a non-null transformer before build().","Use StackFrameTransformers.identity() if no transformation is needed."],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"f3efcbfc9b60d30053b0536d664948d7aa1b8673","analyzedAt":"2026-09-08T13:10:45.570Z","contentChangedAt":"2026-09-08T13:10:45.570Z","schemaVersion":2},"datasetVersion":"2026-09-17T15:17:12.973Z"}