Reflection to call method that had its name changed in an upgrade?

Question

My code compiled with Spark 3.1.2:

private def work(plan: LogicalPlan): LogicalPlan = {
  val result = plan.transformDown {
    // irrelevant details
  }
}

When run with Spark 3.3.0, I run into:

java.lang.NoSuchMethodError: org.apache.spark.sql.catalyst.plans.logical.LogicalPlan.transformDown(Lscala/PartialFunction;)Lorg/apache/spark/sql/catalyst/plans/logical/LogicalPlan;

which makes sense because transformDown doesn't exist anymore in Spark 3.3.0 and seems to now be transformDownWithPruning.

I want to make this work via reflection with the logic:

if (sparkVersion = 3.1.2) plan.transformDown
else if (sparkVersion = 3.3.0) plan.transformDownWithPruning

I know you can call methods by exact name via reflection, but is there any way to get the method to call based on the method name containing a string? In this case it would if it contains "transformDown". I've been writing up the code below, but something like this:

private def transformWithReflection(plan: LogicalPlan) = {
    val runtime = scala.reflect.runtime.universe
    val mirror = runtime.runtimeMirror(getClass.getClassLoader)
    val instanceMirror = mirror.reflect(plan)

    //We target the transformDown method
    val transformMethodAlternatives = runtime
      .typeOf[LogicalPlan]
      .decl(runtime.TermName("transformDown")) // this looks for exact name right?
      .asTerm
      .alternatives
    
    ...
    // call reflected method
}

Or maybe I can get a list of all the methods under this class and filter them by "contains transformDown" which should only be 1 per list and then call that?

Answer 1

I guess there is some misunderstanding.

The class org.apache.spark.sql.catalyst.plans.logical.LogicalPlan itself doesn't have method transformDown either in Spark 3.1.2 or 3.3.0

runtime
  .typeOf[LogicalPlan]
  .decls
  .foreach(println)

// 3.1.2
constructor LogicalPlan
method metadataOutput
method isStreaming
method verboseStringWithSuffix
method maxRows
method maxRowsPerPartition
lazy value resolved
method statePrefix
method childrenResolved
method resolve
lazy value childAttributes
lazy value childMetadataAttributes
lazy value outputAttributes
lazy value outputMetadataAttributes
method resolveChildren
method resolve
method resolveQuoted
method refresh
method outputOrdering
method sameOutput

// 3.3.0
constructor LogicalPlan
method metadataOutput
method isStreaming
lazy value _isStreaming
method verboseStringWithSuffix
method maxRows
method maxRowsPerPartition
lazy value resolved
method statePrefix
method childrenResolved
method resolve
lazy value childAttributes
lazy value childMetadataAttributes
lazy value outputAttributes
lazy value outputMetadataAttributes
method resolveChildren
method resolve
method resolveQuoted
method refresh
method outputOrdering
method sameOutput

https://www.diffchecker.com/gvueXinY/

It's an inherited member and exists both in 3.1.2 and 3.3.0

runtime
  .typeOf[LogicalPlan]
  .members
  .foreach(println)

// 3.1.2
method sameOutput
method outputOrdering
method refresh
method resolveQuoted
method resolve
method resolveChildren
lazy value outputMetadataAttributes
lazy value outputAttributes
lazy value childMetadataAttributes
lazy value childAttributes
method resolve
method childrenResolved
method statePrefix
lazy value resolved
method maxRowsPerPartition
method maxRows
method verboseStringWithSuffix
method isStreaming
method metadataOutput
constructor LogicalPlan
method initializeForcefully
method initializeLogIfNecessary$default$2
method initializeLogIfNecessary
method initializeLogIfNecessary
method isTraceEnabled
method logError
method logWarning
method logTrace
method logDebug
method logInfo
method logError
method logWarning
method logTrace
method logDebug
method logInfo
method log
method logName
method $init$
lazy value validConstraints
lazy value constraints
method constructIsNotNullConstraints
method inferAdditionalConstraints
method invalidateStatsCache
variable statsCache
variable statsCache
method stats
method clone
method transformAllExpressions
method transformUp
method transformDown                            // <--- HERE !!!
method assertNotAnalysisRule
method resolveExpressions
method transformUpWithNewOutput
method resolveOperatorsUpWithNewOutput
method resolveOperatorsDown
method resolveOperatorsUp
method resolveOperators
method analyzed
method setAnalyzed
lazy value allAttributes
method semanticHash
method sameResult
method doCanonicalize
lazy value canonicalized
method isCanonicalizedPlan
method innerChildren
method collectWithSubqueries
method subqueriesAll
method subqueries
method formattedNodeName
method verboseStringWithOperatorId
method simpleStringWithNodeId
method verboseString
method simpleString
method printSchema
method schemaString
lazy value schema
method transformUpWithNewOutput$default$3
method transformUpWithNewOutput$default$2
method expressions
method mapExpressions
method transformExpressionsUp
method transformExpressionsDown
method transformExpressions
method missingInput
lazy value references
method producedAttributes
method inputSet
lazy value outputSet
method conf
method jsonFields
method prettyJson
method toJSON
method asCode
method generateTreeString$default$9
method generateTreeString$default$6
method generateTreeString$default$5
method generateTreeString
method p
method apply
method numberedTreeString
method treeString
method treeString$default$4
method treeString$default$3
method treeString$default$2
method treeString
method treeString
method toString
method argString
method stringArgs
method nodeName
method makeCopy
method otherCopyArgs
method mapChildren
method transform
method withNewChildren
method mapProductIterator
method collectFirst
method collectLeaves
method collect
method flatMap
method map
method foreachUp
method foreach
method find
method fastEquals
method hashCode
lazy value containsChild
method unsetTagValue
method getTagValue
method setTagValue
method copyTagsFrom
value origin
method productPrefix
method productIterator
method synchronized
method ##
method !=
method ==
method ne
method eq
method notifyAll
method notify
method getClass
method equals
method wait
method wait
method wait
method finalize
method asInstanceOf
method isInstanceOf
method output
method children
method productArity
method productElement
method canEqual

// 3.3.0
method sameOutput
method outputOrdering
method refresh
method resolveQuoted
method resolve
method resolveChildren
lazy value outputMetadataAttributes
lazy value outputAttributes
lazy value childMetadataAttributes
lazy value childAttributes
method resolve
method childrenResolved
method statePrefix
lazy value resolved
method maxRowsPerPartition
method maxRows
method verboseStringWithSuffix
lazy value _isStreaming
method isStreaming
method metadataOutput
constructor LogicalPlan
method initializeForcefully
method initializeLogIfNecessary$default$2
method initializeLogIfNecessary
method initializeLogIfNecessary
method isTraceEnabled
method logError
method logWarning
method logTrace
method logDebug
method logInfo
method logError
method logWarning
method logTrace
method logDebug
method logInfo
method log
method logName
method $init$
lazy value validConstraints
lazy value constraints
method constructIsNotNullConstraints
method inferAdditionalConstraints
lazy value distinctKeys
method invalidateStatsCache
variable statsCache
variable statsCache
method stats
method clone
method transformAllExpressionsWithPruning$default$2
method transformAllExpressionsWithPruning
method transformUpWithPruning$default$2
method transformUpWithPruning
method transformDownWithPruning$default$2
method transformDownWithPruning
method assertNotAnalysisRule
method resolveExpressionsWithPruning$default$2
method resolveExpressionsWithPruning
method resolveExpressions
method updateOuterReferencesInSubquery
method transformUpWithNewOutput
method resolveOperatorsUpWithNewOutput
method resolveOperatorsDownWithPruning$default$2
method resolveOperatorsDownWithPruning
method resolveOperatorsDown
method resolveOperatorsUpWithPruning$default$2
method resolveOperatorsUpWithPruning
method resolveOperatorsUp
method resolveOperatorsWithPruning$default$2
method resolveOperatorsWithPruning
method resolveOperators
method analyzed
method setAnalyzed
lazy value allAttributes
method semanticHash
method sameResult
method doCanonicalize
lazy value canonicalized
method isCanonicalizedPlan
method innerChildren
method collectWithSubqueries
method transformDownWithSubqueriesAndPruning$default$2
method transformDownWithSubqueriesAndPruning
method transformDownWithSubqueries
method transformUpWithSubqueries
method transformWithSubqueries
method subqueriesAll
lazy value subqueries
method formattedNodeName
method verboseStringWithOperatorId
method simpleStringWithNodeId
method verboseString
method simpleString
method printSchema
method schemaString
lazy value schema
method rewriteAttrs
method transformUpWithNewOutput$default$3
method transformUpWithNewOutput$default$2
method expressions
method transformAllExpressions
method mapExpressions
method transformExpressionsUpWithPruning$default$2
method transformExpressionsUpWithPruning
method transformExpressionsUp
method transformExpressionsDownWithPruning$default$2
method transformExpressionsDownWithPruning
method transformExpressionsDown
method transformExpressionsWithPruning$default$2
method transformExpressionsWithPruning
method transformExpressions
method missingInput
lazy value deterministic
lazy value references
method producedAttributes
method inputSet
lazy value treePatternBits
lazy value outputSet
method conf
method jsonFields
method prettyJson
method toJSON
method asCode
method generateTreeString$default$9
method generateTreeString$default$6
method generateTreeString$default$5
method generateTreeString
method p
method apply
method numberedTreeString
method treeString
method treeString$default$4
method treeString$default$3
method treeString$default$2
method treeString
method treeString
method toString
method argString
method stringArgs
method nodeName
method makeCopy
method otherCopyArgs
method mapChildren
method transformUpWithBeforeAndAfterRuleOnChildren$default$2
method transformUpWithBeforeAndAfterRuleOnChildren
method transformUp
method transformDown                       // <--- HERE !!!
method transformWithPruning$default$2
method transformWithPruning
method transform
method legacyWithNewChildren
method withNewChildren
method mapProductIterator
method collectFirst
method collectLeaves
method collect
method flatMap
method map
method foreachUp
method foreach
method exists
method find
method fastEquals
method hashCode
lazy value containsChild
method unsetTagValue
method getTagValue
method setTagValue
method copyTagsFrom
method isRuleIneffective
method markRuleAsIneffective
value nodePatterns
method getDefaultTreePatternBits
value origin
method containsAnyPattern
method containsAllPatterns
method containsPattern
method productPrefix
method productIterator
method synchronized
method ##
method !=
method ==
method ne
method eq
method notifyAll
method notify
method getClass
method equals
method wait
method wait
method wait
method finalize
method asInstanceOf
method isInstanceOf
method output
method withNewChildrenInternal
method children
method productArity
method productElement
method canEqual

https://www.diffchecker.com/gKx1ZcYM/

What changed in 3.3.0 in comparison with 3.1.2 is the signature of the method (since the method is inherited you need .member rather than .decl)

println(
  runtime
    .typeOf[LogicalPlan]
    .member(runtime.TermName("transformDown"))
    .typeSignature
)

// 3.1.2
(rule: PartialFunction[org.apache.spark.sql.catalyst.plans.logical.LogicalPlan,org.apache.spark.sql.catalyst.plans.logical.LogicalPlan])org.apache.spark.sql.catalyst.plans.logical.LogicalPlan

// 3.3.0
(rule: PartialFunction[BaseType,BaseType])BaseType

The method is inherited from the class org.apache.spark.sql.catalyst.trees.TreeNode

https://github.com/apache/spark/blob/v3.1.2/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/trees/TreeNode.scala#L316

// 3.1.2
def transformDown(rule: PartialFunction[BaseType, BaseType]): BaseType = {
  ...

https://github.com/apache/spark/blob/v3.3.0/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/trees/TreeNode.scala#L559-L577

// 3.3.0
def transformDown(rule: PartialFunction[BaseType, BaseType]): BaseType = {
  transformDownWithPruning(AlwaysProcess.fn, UnknownRuleId)(rule)
}

...

def transformDownWithPruning(cond: TreePatternBits => Boolean,
  ruleId: RuleId = UnknownRuleId)(rule: PartialFunction[BaseType, BaseType])
: BaseType = {
  ...

What should work both in 3.1.2 and 3.3.0 is static upcasting (with type ascription) to TreeNode

def work(plan: LogicalPlan): LogicalPlan = {
  val result: LogicalPlan = (plan: TreeNode[LogicalPlan]).transformDown {
    case x => x
  }
  result
}

Runtime reflection also should work both in 3.1.2 and 3.3.0

import org.apache.spark.sql.catalyst.ScalaReflection
import ScalaReflection.universe._

def work(plan: LogicalPlan): LogicalPlan = {
  val runtime = ScalaReflection.mirror

  val method = runtime
    .typeOf[LogicalPlan]
    .member(TermName("transformDown"))
    .asMethod

  val result: LogicalPlan = runtime.reflect(plan).reflectMethod(method).apply( {
    case x => x
  }: PartialFunction[LogicalPlan, LogicalPlan]).asInstanceOf[LogicalPlan]

  result
}

In principle, when you'd like to call different methods (this doesn't seem to be your case) you can do this for example with runtime reflection

val name =
  if (sparkVersion == "3.1.2") "transformDown"
  else if (sparkVersion == "3.3.0") "transformDownWithPruning"
  else ???

val method = runtime
  .typeOf[LogicalPlan]
  .member(TermName(name))
  .asMethod

val method = rm
  .typeOf[LogicalPlan]
  .members
  .find(_ == TermName(name))
  .get
  .asMethod

val method = rm
  .typeOf[LogicalPlan]
  .members
  .filter(_.name.toString.startsWith(name))
  .head
  .asMethod

or runtime compilation

// libraryDependencies += scalaOrganization.value % "scala-compiler" % scalaVersion.value exclude("org.scala-lang.modules", "scala-xml_2.12")
import scala.tools.reflect.ToolBox

val tb = runtime.mkToolBox()

tb.eval(
  q"""
    (_: ${typeOf[LogicalPlan]}).${TermName(name)} {
      case x => x
    }
  """
).asInstanceOf[LogicalPlan => LogicalPlan].apply(plan)

NoSuchMethodError: scala.tools.nsc.Settings.usejavacp()Lscala/tools/nsc/settings/AbsSettings$AbsSetting;