fix hanging behavior for constructDataFilters with expression like Eq…

…ualTo(Literal, Literal) (#3059)

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#### Which Delta project/connector is this regarding?
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- [x] Spark
- [ ] Standalone
- [ ] Flink
- [ ] Kernel
- [ ] Other (fill in here)

## Description
This fixes the hanging behavior for `constructDataFilters` with
expressions like `EqualTo(Literal, Literal)`. This is due to infinite
recursion caused by cases like `case EqualTo(v: Literal, a) =>
constructDataFilters(EqualTo(a, v))`. This also fixes the same behavior
for `EqualTo, Not(EqualTo), EqualNullSafe, LessThan, LessThanOrEqual,
GreaterThan, GreaterThanOrEqual`

## How was this patch tested?

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new UT `DataSkippingDeltaConstructDataFiltersSuite`

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

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No

spark/src/main/scala/org/apache/spark/sql/delta/stats/DataSkippingReader.scala

@@ -380,8 +380,11 @@ trait DataSkippingReaderBase
      * manifest as NULL). That case is handled separately by `verifyStatsForFilter` (which disables
      * skipping for any file that lacks the needed stats columns).
      */
-    private def constructDataFilters(dataFilter: Expression):
+    private[stats] def constructDataFilters(dataFilter: Expression):
         Option[DataSkippingPredicate] = dataFilter match {
+      // Expressions that contain only literals are not eligible for skipping.
+      case cmp: Expression if cmp.children.forall(areAllLeavesLiteral) => None
+
       // Push skipping predicate generation through the AND:
       //
       // constructDataFilters(AND(a, b))
@@ -572,6 +575,12 @@ trait DataSkippingReaderBase
       case _ => None
     }
 
+    private def areAllLeavesLiteral(e: Expression): Boolean = e match {
+      case _: Literal => true
+      case _ if e.children.nonEmpty => e.children.forall(areAllLeavesLiteral)
+      case _ => false
+    }
+
     /**
      * An extractor that matches expressions that are eligible for data skipping predicates.
      *

spark/src/test/scala/org/apache/spark/sql/delta/stats/DataSkippingDeltaConstructDataFiltersSuite.scala

@@ -0,0 +1,110 @@
+/*
+ * Copyright (2021) The Delta Lake Project Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.delta.stats
+
+import org.apache.spark.sql.delta.DeltaLog
+
+import org.apache.spark.sql.QueryTest
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.test.SharedSparkSession
+import org.apache.spark.sql.delta.test.DeltaSQLCommandTest
+import org.apache.spark.sql.types.StringType
+
+class DataSkippingDeltaConstructDataFiltersSuite
+    extends QueryTest with SharedSparkSession with DeltaSQLCommandTest {
+  test("Verify constructDataFilters doesn't hang for expressions with Literal operands.") {
+    val snapshot = DeltaLog.forTable(spark, "dummy_path").update()
+    val dataFilterBuilder = new snapshot.DataFiltersBuilder(
+      spark, DeltaDataSkippingType.dataSkippingOnlyV1)
+
+    val literal = Literal.create("foo", StringType)
+    Seq(
+      EqualTo(literal, literal),
+      Not(EqualTo(literal, literal)),
+      EqualNullSafe(literal, literal),
+      Not(EqualNullSafe(literal, literal)),
+      LessThan(literal, literal),
+      LessThanOrEqual(literal, literal),
+      GreaterThan(literal, literal),
+      GreaterThanOrEqual(literal, literal),
+      Not(GreaterThanOrEqual(literal, literal)),
+      In(literal, Seq(literal)),
+      IsNull(literal),
+      IsNotNull(literal),
+      And(EqualTo(literal, literal), LessThan(literal, literal))
+    ).foreach { expression =>
+      assert(dataFilterBuilder.constructDataFilters(expression).isEmpty)
+    }
+  }
+
+  test("Test when the query contains EqualTo(Literal, Literal) in the filter.") {
+    setup {
+      sql(
+        """
+          |explain
+          |select
+          | *
+          |from
+          |  view1 c
+          |  join view2 cv on c.type=cv.type and c.key=cv.key
+          |  join tbl3 b on cv.name=b.name
+          |where
+          |  (
+          |       (b.name="name1" and c.type="foo")
+          |       or
+          |       (b.name="name2" and c.type="bar")
+          |  )
+          |""".stripMargin)
+    }
+  }
+
+  private def setup(f: => Unit) {
+    withTable("tbl1_foo", "tbl1_bar", "tbl2_foo", "tbl2_bar", "tbl3") {
+      Seq("foo", "bar").foreach { tableType =>
+        sql(s"CREATE TABLE tbl1_$tableType (key STRING) USING delta")
+        sql(s"CREATE TABLE tbl2_$tableType (key STRING, name STRING) USING delta")
+      }
+      sql("CREATE TABLE tbl3 (name STRING) USING delta")
+
+      withView("view1", "view2") {
+        sql(
+          s"""
+             |CREATE VIEW view1 (type, key)
+             |AS (
+             |    select 'foo' as type, * from tbl1_foo
+             |    union all
+             |    select 'bar' as type, * from tbl1_bar
+             |)
+             |""".stripMargin
+        )
+
+        sql(
+          s"""
+             |CREATE VIEW view2 (type, key, name)
+             |AS (
+             |    select 'foo' as type, * from tbl2_foo
+             |    union all
+             |    select 'bar' as type, * from tbl2_bar
+             |)
+             |""".stripMargin
+        )
+
+        f
+      }
+    }
+  }
+}