[flink] 02/02: [hotfix][table-planner] Add class header comment to generated code

[tw...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

twalthr pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/flink.git

commit 76b47b219dab18ddb41beb29fa8664110bdb891d
Author: Marios Trivyzas <ma...@gmail.com>
AuthorDate: Thu Dec 2 12:25:27 2021 +0100

    [hotfix][table-planner] Add class header comment to generated code
    
    Use a class header comment to add useful configuration variables that can
    help debugging a generated class code. Added timezone and legacy behaviour
    info in this comment on the generated class implementing CAST.
---
 .../planner/codegen/CodeGeneratorContext.scala     | 25 ++++++++++++++++++++++
 .../planner/codegen/FunctionCodeGenerator.scala    |  1 +
 .../planner/codegen/calls/ScalarOperatorGens.scala |  6 ++++++
 3 files changed, 32 insertions(+)

diff --git a/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/CodeGeneratorContext.scala b/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/CodeGeneratorContext.scala
index 3be8032..6ddcbe7 100644
--- a/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/CodeGeneratorContext.scala
+++ b/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/CodeGeneratorContext.scala
@@ -51,6 +51,10 @@ class CodeGeneratorContext(val tableConfig: TableConfig) {
   // holding a list of objects that could be used passed into generated class
   val references: mutable.ArrayBuffer[AnyRef] = new mutable.ArrayBuffer[AnyRef]()
 
+  // set of strings (lines) that will be concatenated into a single class header comment
+  private val reusableHeaderComments: mutable.LinkedHashSet[String] =
+    mutable.LinkedHashSet[String]()
+
   // set of member statements that will be added only once
   // we use a LinkedHashSet to keep the insertion order
   private val reusableMemberStatements: mutable.LinkedHashSet[String] =
@@ -143,6 +147,16 @@ class CodeGeneratorContext(val tableConfig: TableConfig) {
 
   def nullCheck: Boolean = tableConfig.getNullCheck
 
+
+  /**
+    * Add a line comment to [[reusableHeaderComments]] list which will be concatenated
+    * into a single class header comment.
+    * @param comment The comment to add for class header
+    */
+  def addReusableHeaderComment(comment: String): Unit = {
+    reusableHeaderComments.add(comment)
+  }
+
   // ---------------------------------------------------------------------------------
   // Local Variables for Code Split
   // ---------------------------------------------------------------------------------
@@ -197,6 +211,17 @@ class CodeGeneratorContext(val tableConfig: TableConfig) {
   // ---------------------------------------------------------------------------------
 
   /**
+    * @return Comment to be added as a header comment on the generated class
+    */
+  def getClassHeaderComment(): String = {
+    s"""
+    |/*
+    | * ${reusableHeaderComments.mkString("\n * ")}
+    | */
+    """.stripMargin
+  }
+
+  /**
     * @return code block of statements that need to be placed in the member area of the class
     *         (e.g. inner class definition)
     */
diff --git a/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/FunctionCodeGenerator.scala b/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/FunctionCodeGenerator.scala
index 44a4c23..24c286f 100644
--- a/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/FunctionCodeGenerator.scala
+++ b/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/FunctionCodeGenerator.scala
@@ -125,6 +125,7 @@ object FunctionCodeGenerator {
 
     val funcCode =
       j"""
+      ${ctx.getClassHeaderComment()}
       public class $funcName
           extends ${samHeader._1.getCanonicalName} {
 
diff --git a/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/calls/ScalarOperatorGens.scala b/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/calls/ScalarOperatorGens.scala
index 045976c..61252f4 100644
--- a/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/calls/ScalarOperatorGens.scala
+++ b/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/codegen/calls/ScalarOperatorGens.scala
@@ -937,6 +937,12 @@ object ScalarOperatorGens {
       operand: GeneratedExpression,
       targetType: LogicalType)
     : GeneratedExpression = {
+
+    ctx.addReusableHeaderComment(
+      s"Using option '${ExecutionConfigOptions.TABLE_EXEC_LEGACY_CAST_BEHAVIOUR.key()}':" +
+        s"'${isLegacyCastBehaviourEnabled(ctx)}'")
+    ctx.addReusableHeaderComment("Timezone: " + ctx.tableConfig.getLocalTimeZone)
+
     // Try to use the new cast rules
     val rule = CastRuleProvider.resolve(operand.resultType, targetType)
     rule match {