[SPARK-50370][SQL] Codegen Support for json_tuple

[panbingkun]

What changes were proposed in this pull request?

The pr aims to add Codegen Support for JsonTuple(json_tuple).

Why are the changes needed?

• improve codegen coverage.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

• Pass GA & Existed UT (eg: JsonFunctionsSuite#*json_tuple*, JsonExpressionsSuite#*json_tuple*)
• Updated existed UT.

Was this patch authored or co-authored using generative AI tooling?

No.

[dongjoon-hyun]

BTW, FYI, I added you to the Apache Spark Committers group in ASF JIRA system in a few minutes ago.

BEFORE

AFTER

[panbingkun]

BTW, FYI, I added you to the Apache Spark Committers group in ASF JIRA system in a few minutes ago.

BEFORE

AFTER

Oh, great, thank you! ❤️

[panbingkun]

• after implementing codegen for json_tuple, it seems that this usage (GenerateUnsafeProjection.generate(JsonTuple(...))) is no longer supported, such as the following:
  

  spark/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/generators.scala

  Lines 255 to 256 in d5da49d

  	override protected def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
  	// Rows - we write these into an array.

test("stack") {
    GenerateUnsafeProjection.generate(
      Stack(Seq(2, 1, 2, 3).map(Literal(_))) :: Nil)
  }

• which is also not supported and throw an exception.

19:59:59.933 ERROR org.apache.spark.sql.catalyst.expressions.codegen.CodeGenerator: Failed to compile the generated Java code.
org.codehaus.commons.compiler.CompileException: File 'generated.java', Line 78, Column 30: Assignment conversion not possible from type "scala.collection.mutable.ArraySeq" to type "org.apache.spark.sql.catalyst.util.ArrayData"
	at org.codehaus.janino.UnitCompiler.compileError(UnitCompiler.java:13014)
	at org.codehaus.janino.UnitCompiler.assignmentConversion(UnitCompiler.java:11263)
	at org.codehaus.janino.UnitCompiler.access$3900(UnitCompiler.java:236)
	at org.codehaus.janino.UnitCompiler$7.visitRvalue(UnitCompiler.java:2764)
	at org.codehaus.janino.UnitCompiler$7.visitRvalue(UnitCompiler.java:2754)
	at org.codehaus.janino.Java$Rvalue.accept(Java.java:4498)
	at org.codehaus.janino.UnitCompiler.compile(UnitCompiler.java:2754)
19:59:59.940 ERROR org.apache.spark.sql.catalyst.expressions.codegen.CodeGenerator: 
/* 001 */ public java.lang.Object generate(Object[] references) {
/* 002 */   return new SpecificUnsafeProjection(references);
/* 003 */ }
/* 004 */
/* 005 */ class SpecificUnsafeProjection extends org.apache.spark.sql.catalyst.expressions.UnsafeProjection {
/* 006 */
/* 007 */   private Object[] references;
/* 008 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeArrayWriter[] mutableStateArray_2 = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeArrayWriter[1];
/* 009 */   p...

• therefore, the testing approach has been modified here with the same ultimate goal.

[panbingkun]

cc @cloud-fan @MaxGekk