{"record":{"id":"1d5e709228d48289","repo":"apache/beam","slug":"no-producer-for-s","errorCode":null,"errorMessage":"No producer for %s","messagePattern":"No producer for (.+?)","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"sdks/python/apache_beam/pipeline.py","lineNumber":1190,"sourceCode":"        })\n    from apache_beam.runners import pipeline_context\n    context = pipeline_context.PipelineContext(\n        proto.components, requirements=proto.requirements)\n    if proto.root_transform_ids:\n      root_transform_id, = proto.root_transform_ids\n      p.transforms_stack = [context.transforms.get_by_id(root_transform_id)]\n    else:\n      p.transforms_stack = [AppliedPTransform(None, None, '', None, None, None)]\n    # TODO(robertwb): These are only needed to continue construction. Omit?\n    p.applied_labels = {\n        t.unique_name\n        for t in proto.components.transforms.values()\n    }\n    for id in proto.components.pcollections:\n      pcollection = context.pcollections.get_by_id(id)\n      pcollection.pipeline = p\n      if not pcollection.producer:\n        raise ValueError('No producer for %s' % id)\n\n    # Inject PBegin input where necessary.\n    from apache_beam.io.iobase import Read\n    from apache_beam.transforms.core import Create\n    has_pbegin = [Read, Create]\n    for id in proto.components.transforms:\n      transform = context.transforms.get_by_id(id)\n      if not transform.inputs and transform.transform.__class__ in has_pbegin:\n        transform.main_inputs = {'None': pvalue.PBegin(p)}\n\n    if return_context:\n      return p, context  # type: ignore  # too complicated for now\n    else:\n      return p\n\n\nclass PipelineVisitor(object):\n  \"\"\"For internal use only; no backwards-compatibility guarantees.","sourceCodeStart":1172,"sourceCodeEnd":1208,"githubUrl":"https://github.com/apache/beam/blob/12126d8942aaf848030c478b4c6a28c6af861c66/sdks/python/apache_beam/pipeline.py#L1172-L1208","documentation":"Raised during Pipeline.from_runner_api when deserializing a pipeline proto that contains a PCollection with no producing transform. Every PCollection in a valid pipeline graph must be generated by some transform; Beam throws because the reconstructed graph would be incomplete.","triggerScenarios":"Loading a hand-edited, truncated, or corrupted pipeline JSON/proto; constructing runner-api protos manually and forgetting to register the producing transform; pipeline fragments saved without their upstream transforms.","commonSituations":"Custom runners manipulating pipeline protos; cross-language pipelines where component protos are assembled programmatically and an id is mistyped.","solutions":["Ensure the proto's transforms include the transform whose output id matches the PCollection id","Regenerate the pipeline proto from a working pipeline rather than hand-editing it","Validate the serialized pipeline JSON references consistent pcollection/transform ids"],"exampleFix":null,"handlingStrategy":"validation","validationCode":"for pc_id in proto.components.pcollections:\n    assert pc_id in set().union(*[set(t.outputs) for t in proto.components.transforms.values()]), f'No producer for {pc_id}'","typeGuard":null,"tryCatchPattern":"try:\n    p = Pipeline.from_runner_api(proto, runner, options)\nexcept ValueError as e:\n    logging.error('Corrupt pipeline proto: %s', e)","preventionTips":["Never hand-edit runner-api protos; regenerate from a live pipeline","Validate pipeline JSON with the Beam schema after external manipulation","Keep transform and pcollection ids consistent when assembling protos programmatically"],"tags":["python","apache-beam","runner-api","deserialization"],"backgroundTag":"internal-invariant-violation","analyzedSha":"12126d8942aaf848030c478b4c6a28c6af861c66","analyzedAt":"2026-09-13T01:50:10.254Z","contentChangedAt":"2026-09-13T01:50:10.254Z","schemaVersion":2},"datasetVersion":"2026-09-14T16:17:12.679Z"}