{"record":{"id":"8ab0807cfa886a0b","repo":"hyperledger/fabric","slug":"error-while-reading-from-snapshot-file-s","errorCode":null,"errorMessage":"error while reading from snapshot file: %s","messagePattern":"error while reading from snapshot file: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"common/ledger/snapshot/file.go","lineNumber":178,"sourceCode":"\treturn string(b), err\n}\n\n// DecodeBytes reads and decodes bytes\nfunc (r *FileReader) DecodeBytes() ([]byte, error) {\n\tb, err := r.decodeBytes()\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\tc := make([]byte, len(b))\n\tcopy(c, b)\n\treturn c, nil\n}\n\n// DecodeUVarInt reads and decodes a number\nfunc (r *FileReader) DecodeUVarInt() (uint64, error) {\n\tu, err := binary.ReadUvarint(r.bufReader)\n\tif err != nil {\n\t\treturn 0, errors.Wrapf(err, \"error while reading from snapshot file: %s\", r.file.Name())\n\t}\n\treturn u, nil\n}\n\n// DecodeProtoMessage reads and decodes a protoMessage\nfunc (r *FileReader) DecodeProtoMessage(m proto.Message) error {\n\tb, err := r.decodeBytes()\n\tif err != nil {\n\t\treturn err\n\t}\n\treturn proto.Unmarshal(b, m)\n}\n\n// Close closes the file\nfunc (r *FileReader) Close() error {\n\tif r == nil {\n\t\treturn nil\n\t}","sourceCodeStart":160,"sourceCodeEnd":196,"githubUrl":"https://github.com/hyperledger/fabric/blob/2736b63f8fd5932511d56fe68b7039d15977f7f6/common/ledger/snapshot/file.go#L160-L196","documentation":"FileReader.DecodeUVarInt wraps any error returned by binary.ReadUvarint (EOF, unexpected EOF, corrupted varint) with the snapshot file name. It signals that a variable-length integer could not be read from the snapshot file stream, usually because the file is truncated or was not written in the expected encoded format. Callers such as decodeBytes, readMetadata, and the export flow abort reading the snapshot when this fires.","triggerScenarios":"Calling DecodeUVarInt on a FileReader whose underlying file is empty, truncated, or whose byte stream is not a valid uvarint (e.g. reading a file produced by a different writer/version, or seeking to a wrong offset).","commonSituations":"Partial snapshot file from a crashed export; opening a snapshot file written by an incompatible Fabric version; reading past the end of the metadata section due to a corrupted length prefix.","solutions":["Verify the snapshot file exists, is non-empty, and is fully written (compare size/checksum if available).","Re-export or regenerate the snapshot file from the source ledger.","Check that the file was written by a compatible version of the snapshot writer.","Inspect the wrapped cause (errors.Unwrap / %v of the error) to distinguish io.EOF from ErrCorrupt varint data."],"exampleFix":"// before\nu, err := reader.DecodeUVarInt()\nif err != nil { return err }\n// after\nu, err := reader.DecodeUVarInt()\nif err != nil {\n  if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {\n    return fmt.Errorf(\"snapshot file truncated or incomplete: %w\", err)\n  }\n  return err\n}","handlingStrategy":"try-catch","validationCode":"fi, err := os.Stat(path)\nif err != nil || fi.Size() == 0 { return fmt.Errorf(\"snapshot file %s missing or empty\", path) }","typeGuard":"func isSnapshotReadErr(err error) bool {\n  return err != nil && strings.Contains(err.Error(), \"error while reading from snapshot file\")\n}","tryCatchPattern":"u, err := reader.DecodeUVarInt()\nif err != nil {\n  if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {\n    return fmt.Errorf(\"truncated snapshot: %w\", err)\n  }\n  return err\n}","preventionTips":["Verify file size/checksum before decoding","Never read snapshot files while they are still being written","Match reader and writer format versions","Keep the FileReader open only within a single well-scoped decode function"],"tags":["ledger","snapshot","io","golang"],"backgroundTag":"file-read-during-snapshot-failed","analyzedSha":"2736b63f8fd5932511d56fe68b7039d15977f7f6","analyzedAt":"2026-09-04T08:52:36.465Z","contentChangedAt":"2026-09-04T08:52:36.465Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}