stefankandic commented on code in PR #46280: URL: https://github.com/apache/spark/pull/46280#discussion_r1595218281
########## 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: I added a test to be sure this works, but I don't see why we would need any special logic for this case. Even if we have a column `name.key` this will never be ambiguous in the metadata as the struct field could be a string or a map but never both, so parsing will just work regardless - we could never have a case of adding the collation two times. -- 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