[
https://issues.apache.org/jira/browse/SPARK-55681?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Tim Lee updated SPARK-55681:
----------------------------
Description:
When a singleton DataType (e.g., BinaryType, IntegerType) is deserialized by a
framework that bypasses readResolve() — such as Kryo with certain
configurations — a new instance of the class is created instead of returning
the case object singleton. This non-singleton instance then fails pattern
matching at every `case BinaryType =>` site in the codebase, because Scala case
object matching relies on equals(), which defaults to reference equality.
The failure manifests as silent match fallthrough, leading to errors like:
{code:java}
IllegalStateException: The data type 'binary' is not supported in generating a
writer function... {code}
The issue affects all 14 singleton DataType classes that use the `class + case
object` pattern without an explicit equals() override:
{code:java}
BinaryType, BooleanType, ByteType, ShortType, IntegerType, LongType, FloatType,
DoubleType, DateType, TimestampType, TimestampNTZType, NullType,
CalendarIntervalType, VariantType {code}
Other DataTypes already handle this correctly:
# VarcharType, CharType, TimeType, GeometryType, GeographyType — matched by
type (`case _: XType =>`) rather than value
# StringType — has custom equals() comparing collationId
# DecimalType, ArrayType, MapType, StructType — case classes with
auto-generated equals()
*Proposed fix:* Override equals() and hashCode() on the 14 affected classes:
{code:java}
override def equals(obj: Any): Boolean = obj.isInstanceOf[XType]
override def hashCode(): Int = classOf[XType].getSimpleName.hashCode {code}
getSimpleName is used because Scala's auto-generated hashCode for 0-arity case
objects returns productPrefix.hashCode (the simple class name). This preserves
the original hash values, avoiding any behavioral change for code that depends
on DataType hashCodes (e.g., HashMap/HashSet lookups, canonicalization
ordering).
The change is strictly additive: singleton-to-singleton equality is unchanged;
only the non-singleton edge case gains correct behavior. Although the
constructors are private, this is a compile-time guard only – serialization
frameworks bypass constructors at runtime.
was:
When a singleton DataType (e.g., BinaryType, IntegerType) is deserialized by a
framework that bypasses readResolve() — such as Kryo with certain
configurations — a new instance of the class is created instead
of returning the case object singleton. This non-singleton instance then
fails pattern matching at every `case BinaryType =>` site in the codebase,
because Scala case object matching relies on equals(),
which defaults to reference equality.
The failure manifests as silent match fallthrough, leading to errors like:
\{code}
IllegalStateException: The data type 'binary' is not supported in generating
a writer function...
\{code}
The issue affects all 14 singleton DataType classes that use the `class +
case object` pattern without an explicit equals() override:
BinaryType, BooleanType, ByteType, ShortType, IntegerType, LongType,
FloatType, DoubleType, DateType, TimestampType, TimestampNTZType, NullType,
CalendarIntervalType, VariantType
Other DataTypes already handle this correctly:
- VarcharType, CharType, TimeType, GeometryType, GeographyType — matched by
type (`case _: XType =>`) rather than value
- StringType — has custom equals() comparing collationId
- DecimalType, ArrayType, MapType, StructType — case classes with
auto-generated equals()
*Proposed fix:* Override equals() and hashCode() on the 14 affected classes:
\{code:scala}
override def equals(obj: Any): Boolean = obj.isInstanceOf[XType]
override def hashCode(): Int = classOf[XType].getSimpleName.hashCode
\{code}
getSimpleName is used because Scala's auto-generated hashCode for 0-arity
case objects returns productPrefix.hashCode (the simple class name). This
preserves the original hash values, avoiding any behavioral
change for code that depends on DataType hashCodes (e.g., HashMap/HashSet
lookups, canonicalization ordering).
The change is strictly additive: singleton-to-singleton equality is
unchanged; only the non-singleton edge case gains correct behavior. Although
the constructors are private, this is a compile-time guard only
— serialization frameworks bypass constructors at runtime.
> Singleton DataType equality fails after deserialization
> -------------------------------------------------------
>
> Key: SPARK-55681
> URL: https://issues.apache.org/jira/browse/SPARK-55681
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 4.1.1
> Reporter: Tim Lee
> Priority: Major
>
> When a singleton DataType (e.g., BinaryType, IntegerType) is deserialized by
> a framework that bypasses readResolve() — such as Kryo with certain
> configurations — a new instance of the class is created instead of returning
> the case object singleton. This non-singleton instance then fails pattern
> matching at every `case BinaryType =>` site in the codebase, because Scala
> case object matching relies on equals(), which defaults to reference equality.
> The failure manifests as silent match fallthrough, leading to errors like:
> {code:java}
> IllegalStateException: The data type 'binary' is not supported in generating
> a writer function... {code}
>
> The issue affects all 14 singleton DataType classes that use the `class +
> case object` pattern without an explicit equals() override:
>
> {code:java}
> BinaryType, BooleanType, ByteType, ShortType, IntegerType, LongType,
> FloatType, DoubleType, DateType, TimestampType, TimestampNTZType, NullType,
> CalendarIntervalType, VariantType {code}
>
> Other DataTypes already handle this correctly:
> # VarcharType, CharType, TimeType, GeometryType, GeographyType — matched by
> type (`case _: XType =>`) rather than value
> # StringType — has custom equals() comparing collationId
> # DecimalType, ArrayType, MapType, StructType — case classes with
> auto-generated equals()
> *Proposed fix:* Override equals() and hashCode() on the 14 affected
> classes:
> {code:java}
> override def equals(obj: Any): Boolean = obj.isInstanceOf[XType]
> override def hashCode(): Int = classOf[XType].getSimpleName.hashCode {code}
> getSimpleName is used because Scala's auto-generated hashCode for 0-arity
> case objects returns productPrefix.hashCode (the simple class name). This
> preserves the original hash values, avoiding any behavioral change for code
> that depends on DataType hashCodes (e.g., HashMap/HashSet lookups,
> canonicalization ordering).
> The change is strictly additive: singleton-to-singleton equality is
> unchanged; only the non-singleton edge case gains correct behavior. Although
> the constructors are private, this is a compile-time guard only –
> serialization frameworks bypass constructors at runtime.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
