[SPARK-33847][SQL][FOLLOWUP] Remove the CaseWhen should consider deterministic

### What changes were proposed in this pull request?

This pr fix remove the `CaseWhen` if elseValue is empty and other outputs are null because of we should consider deterministic.

### Why are the changes needed?

Fix bug.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Unit test.

Closes #30960 from wangyum/SPARK-33847-2.

Authored-by: Yuming Wang <yumwang@ebay.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/ReplaceNullWithFalseInPredicate.scala

@@ -98,12 +98,8 @@ object ReplaceNullWithFalseInPredicate extends Rule[LogicalPlan] {
       val newBranches = cw.branches.map { case (cond, value) =>
         replaceNullWithFalse(cond) -> replaceNullWithFalse(value)
       }
-      if (newBranches.forall(_._2 == FalseLiteral) && cw.elseValue.isEmpty) {
-        FalseLiteral
-      } else {
-        val newElseValue = cw.elseValue.map(replaceNullWithFalse)
-        CaseWhen(newBranches, newElseValue)
-      }
+      val newElseValue = cw.elseValue.map(replaceNullWithFalse).getOrElse(FalseLiteral)
+      CaseWhen(newBranches, newElseValue)
     case i @ If(pred, trueVal, falseVal) if i.dataType == BooleanType =>
       If(replaceNullWithFalse(pred), replaceNullWithFalse(trueVal), replaceNullWithFalse(falseVal))
     case e if e.dataType == BooleanType =>

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

@@ -515,8 +515,9 @@ object SimplifyConditionals extends Rule[LogicalPlan] with PredicateHelper {
         val (h, t) = branches.span(_._1 != TrueLiteral)
         CaseWhen( h :+ t.head, None)
 
-      case e @ CaseWhen(branches, Some(elseValue))
-          if branches.forall(_._2.semanticEquals(elseValue)) =>
+      case e @ CaseWhen(branches, elseOpt)
+          if branches.forall(_._2.semanticEquals(elseOpt.getOrElse(Literal(null, e.dataType)))) =>
+        val elseValue = elseOpt.getOrElse(Literal(null, e.dataType))
         // For non-deterministic conditions with side effect, we can not remove it, or change
         // the ordering. As a result, we try to remove the deterministic conditions from the tail.
         var hitNonDeterministicCond = false
@@ -532,10 +533,6 @@ object SimplifyConditionals extends Rule[LogicalPlan] with PredicateHelper {
         } else {
           e.copy(branches = branches.take(i).map(branch => (branch._1, elseValue)))
         }
-
-      case e @ CaseWhen(branches, None)
-          if branches.forall(_._2.semanticEquals(Literal(null, e.dataType))) =>
-        Literal(null, e.dataType)
     }
   }
 }

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/PushFoldableIntoBranchesSuite.scala

@@ -260,14 +260,13 @@ class PushFoldableIntoBranchesSuite
   }
 
   test("SPARK-33847: Remove the CaseWhen if elseValue is empty and other outputs are null") {
-    Seq(a, LessThan(Rand(1), Literal(0.5))).foreach { condition =>
-      assertEquivalent(
-        EqualTo(CaseWhen(Seq((condition, Literal.create(null, IntegerType)))), Literal(2)),
-        Literal.create(null, BooleanType))
-      assertEquivalent(
-        EqualTo(CaseWhen(Seq((condition, Literal("str")))).cast(IntegerType), Literal(2)),
-        Literal.create(null, BooleanType))
-    }
+    assertEquivalent(
+      EqualTo(CaseWhen(Seq((a, Literal.create(null, IntegerType)))), Literal(2)),
+      Literal.create(null, BooleanType))
+    assertEquivalent(
+      EqualTo(CaseWhen(Seq((LessThan(Rand(1), Literal(0.5)), Literal("str")))).cast(IntegerType),
+        Literal(2)),
+      CaseWhen(Seq((LessThan(Rand(1), Literal(0.5)), Literal.create(null, BooleanType)))))
   }
 
   test("SPARK-33884: simplify CaseWhen clauses with (true and false) and (false and true)") {

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/ReplaceNullWithFalseInPredicateSuite.scala

@@ -114,7 +114,7 @@ class ReplaceNullWithFalseInPredicateSuite extends PlanTest {
     val expectedBranches = Seq(
       (UnresolvedAttribute("i") < Literal(10)) -> FalseLiteral,
       (UnresolvedAttribute("i") > Literal(40)) -> TrueLiteral)
-    val expectedCond = CaseWhen(expectedBranches)
+    val expectedCond = CaseWhen(expectedBranches, FalseLiteral)
 
     testFilter(originalCond, expectedCond)
     testJoin(originalCond, expectedCond)
@@ -135,7 +135,7 @@ class ReplaceNullWithFalseInPredicateSuite extends PlanTest {
       (UnresolvedAttribute("i") < Literal(10)) -> TrueLiteral,
       (UnresolvedAttribute("i") > Literal(10)) -> FalseLiteral,
       TrueLiteral -> TrueLiteral)
-    val expectedCond = CaseWhen(expectedBranches)
+    val expectedCond = CaseWhen(expectedBranches, FalseLiteral)
 
     testFilter(originalCond, expectedCond)
     testJoin(originalCond, expectedCond)
@@ -238,7 +238,8 @@ class ReplaceNullWithFalseInPredicateSuite extends PlanTest {
       FalseLiteral)
     val condition = CaseWhen(Seq((UnresolvedAttribute("i") > Literal(10)) -> branchValue))
     val expectedCond = CaseWhen(Seq(
-      (UnresolvedAttribute("i") > Literal(10), (Literal(2) === nestedCaseWhen) <=> TrueLiteral)))
+      (UnresolvedAttribute("i") > Literal(10), (Literal(2) === nestedCaseWhen) <=> TrueLiteral)),
+      FalseLiteral)
     testFilter(originalCond = condition, expectedCond = expectedCond)
     testJoin(originalCond = condition, expectedCond = expectedCond)
     testDelete(originalCond = condition, expectedCond = expectedCond)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SimplifyConditionalSuite.scala

@@ -237,11 +237,13 @@ class SimplifyConditionalSuite extends PlanTest with ExpressionEvalHelper with P
   }
 
   test("SPARK-33847: Remove the CaseWhen if elseValue is empty and other outputs are null") {
-    Seq(GreaterThan('a, 1), GreaterThan(Rand(0), 1)).foreach { condition =>
-      assertEquivalent(
-        CaseWhen((condition, Literal.create(null, IntegerType)) :: Nil, None),
-        Literal.create(null, IntegerType))
-    }
+    assertEquivalent(
+      CaseWhen((GreaterThan('a, 1), Literal.create(null, IntegerType)) :: Nil, None),
+      Literal.create(null, IntegerType))
+
+    assertEquivalent(
+      CaseWhen((GreaterThan(Rand(0), 0.5), Literal.create(null, IntegerType)) :: Nil, None),
+      CaseWhen((GreaterThan(Rand(0), 0.5), Literal.create(null, IntegerType)) :: Nil, None))
   }
 
   test("SPARK-33884: simplify CaseWhen clauses with (true and false) and (false and true)") {