cloud-fan commented on code in PR #46280: URL: https://github.com/apache/spark/pull/46280#discussion_r1595169435
########## sql/api/src/main/scala/org/apache/spark/sql/types/StructField.scala: ########## @@ -63,7 +66,60 @@ case class StructField( ("name" -> name) ~ ("type" -> dataType.jsonValue) ~ ("nullable" -> nullable) ~ - ("metadata" -> metadata.jsonValue) + ("metadata" -> metadataJson) + } + + private def metadataJson: JValue = { + val metadataJsonValue = metadata.jsonValue + metadataJsonValue match { + case JObject(fields) if collationMetadata.nonEmpty => + val collationFields = collationMetadata.map(kv => kv._1 -> JString(kv._2)).toList + JObject(fields :+ (DataType.COLLATIONS_METADATA_KEY -> JObject(collationFields))) + + case _ => metadataJsonValue + } + } + + /** Map of field path to collation name. */ + private lazy val collationMetadata: mutable.Map[String, String] = { + val fieldToCollationMap = mutable.Map[String, String]() + + def visitRecursively(dt: DataType, path: String): Unit = dt match { + case at: ArrayType => + processDataType(at.elementType, path + ".element") + + case mt: MapType => + processDataType(mt.keyType, path + ".key") + processDataType(mt.valueType, path + ".value") + + case st: StringType if isCollatedString(st) => + fieldToCollationMap(path) = collationName(st) + + case _ => + } + + def processDataType(dt: DataType, path: String): Unit = { + if (isCollatedString(dt)) { + fieldToCollationMap(path) = collationName(dt) + } else { + visitRecursively(dt, path) + } + } + + visitRecursively(dataType, name) Review Comment: This is per field metadata, do we really need to put the filed name in the path key? My worry is that the field name can contain special chars, e.g. `name.key`, which may cause issues without proper quoting. How about we use empty string as the path key for the top-level field? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org