{"record":{"id":"8d280a2fbf216daa","repo":"apache/beam","slug":"cannot-convert-schema-field-v-to-field","errorCode":null,"errorMessage":"cannot convert schema field %v to field","messagePattern":"cannot convert schema field (.+?) to field","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"sdks/go/pkg/beam/core/runtime/graphx/schema/schema.go","lineNumber":714,"sourceCode":"\treturn r.toType(s)\n}\n\n// toType must only be called while holding the r.rwmu lock (read or write)\nfunc (r *Registry) toType(s *pipepb.Schema) (reflect.Type, error) {\n\tif t, ok := r.idToType[s.GetId()]; ok {\n\t\treturn t, nil\n\t}\n\tif lID, ok := fromLogicalOption(s.GetOptions()); ok {\n\t\tif lt, ok := r.logicalTypes[lID]; ok {\n\t\t\treturn lt.GoType(), nil\n\t\t}\n\t}\n\n\tfields := make([]reflect.StructField, 0, len(s.GetFields()))\n\tfor _, sf := range s.GetFields() {\n\t\trf, err := r.fieldToStructField(sf)\n\t\tif err != nil {\n\t\t\treturn nil, errors.Wrapf(err, \"cannot convert schema field %v to field\", sf.GetName())\n\t\t}\n\t\tif checkOptions(sf.Options, optGoEmbeddedUrn) != nil {\n\t\t\trf.Anonymous = true\n\t\t}\n\t\tfields = append(fields, rf)\n\t}\n\tret := reflect.StructOf(fields)\n\tif ut, ok := r.syntheticToUser[ret]; ok {\n\t\tret = ut\n\t}\n\tif t := nillableFromOptions(s.GetOptions(), ret); t != nil {\n\t\treturn t, nil\n\t}\n\treturn ret, nil\n}\n\nfunc (r *Registry) fieldToStructField(sf *pipepb.Field) (reflect.StructField, error) {\n\tname := sf.GetName()","sourceCodeStart":696,"sourceCodeEnd":732,"githubUrl":"https://github.com/apache/beam/blob/12126d8942aaf848030c478b4c6a28c6af861c66/sdks/go/pkg/beam/core/runtime/graphx/schema/schema.go#L696-L732","documentation":"Raised in Registry.toType while rebuilding a Go reflect.Struct from a pipepb.Schema: one of the schema fields could not be converted back into a reflect.StructField via fieldToStructField. The error wraps the underlying cause (an unknown FieldType, an unregistered logical type URN, etc.) and names the failing field.","triggerScenarios":"Calling ToType (or registerType/fieldTypeToReflectType paths) on a schema that contains a field whose type is not representable — e.g. a logical type URN not registered in this process, or an atomic type unknown to atomicTypeToReflectType.","commonSituations":"Cross-language or serialized pipelines whose schemas reference logical types that were never registered on the Go side; schema produced by another SDK (Python/Java) with types Go cannot reconstruct.","solutions":["Read the wrapped error and the field name to find the unconvertible field","Register the missing logical type (same URN) with schema.RegisterLogicalType before calling ToType","Check for typos or version skew between the schema producer and the Go registry","Replace the field with a standard atomic/row type in the schema producer"],"exampleFix":"// before: ToType fails because URN unknown\n// after: register it first\nschema.RegisterLogicalType(myLogicalTypeProvider{}) // registers urn \"acme:ts\"","handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"t, err := registry.ToType(s)\nif err != nil {\n  var fieldName string\n  if strings.Contains(err.Error(), \"cannot convert schema field\") {\n    fmt.Sscanf(err.Error(), \"cannot convert schema field %s\", &fieldName)\n  }\n  return fmt.Errorf(\"field %q unconvertible: %w\", fieldName, err)\n}","preventionTips":["Ensure every logical-type URN used by producers is registered in the Go process","Keep schema-producing and schema-consuming SDK versions in sync","Validate cross-language schemas against the Go registry in integration tests"],"tags":["go","apache-beam","schema","type-conversion"],"backgroundTag":"schema-validation-failed","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"}