[SPARK-42899] DataFrame.to(schema) fails when it contains non-nullable nested field in nullable field

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.1
• Component/s: SQL
• Assignee: Takuya Ueshin
• Reporter: Takuya Ueshin
• Created: 22/Mar/23 21:53
• Updated: 23/Mar/23 02:16
• Resolved: 23/Mar/23 02:16

Description

DataFrame.to(schema) fails when it contains non-nullable nested field in nullable field:

scala> val df = spark.sql("VALUES (1, STRUCT(1 as i)), (NULL, NULL) as t(a, b)")
df: org.apache.spark.sql.DataFrame = [a: int, b: struct<i: int>]
scala> df.printSchema()
root
 |-- a: integer (nullable = true)
 |-- b: struct (nullable = true)
 |    |-- i: integer (nullable = false)

scala> df.to(df.schema)
org.apache.spark.sql.AnalysisException: [NULLABLE_COLUMN_OR_FIELD] Column or field `b`.`i` is nullable while it's required to be non-nullable.