[SPARK-16947][SQL] Support type coercion and foldable expression for inline tables

## What changes were proposed in this pull request?
This patch improves inline table support with the following:

1. Support type coercion.
2. Support using foldable expressions. Previously only literals were supported.
3. Improve error message handling.
4. Improve test coverage.

## How was this patch tested?
Added a new unit test suite ResolveInlineTablesSuite and a new file-based end-to-end test inline-table.sql.

Author: petermaxlee <petermaxlee@gmail.com>

Closes #14676 from petermaxlee/SPARK-16947.

5 files changed, 150 insertions, 32 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
index 333dd4d9a4..41e0e6d65e 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
@@ -108,6 +108,7 @@ class Analyzer(
       GlobalAggregates ::
       ResolveAggregateFunctions ::
       TimeWindowing ::
+      ResolveInlineTables ::
       TypeCoercion.typeCoercionRules ++
       extendedResolutionRules : _*),
     Batch("Nondeterministic", Once,
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveInlineTables.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveInlineTables.scala
new file mode 100644
index 0000000000..7323197b10
--- /dev/null
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveInlineTables.scala
@@ -0,0 +1,112 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.catalyst.analysis
+
+import scala.util.control.NonFatal
+
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.expressions.Cast
+import org.apache.spark.sql.catalyst.plans.logical.{LocalRelation, LogicalPlan}
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.types.{StructField, StructType}
+
+/**
+ * An analyzer rule that replaces [[UnresolvedInlineTable]] with [[LocalRelation]].
+ */
+object ResolveInlineTables extends Rule[LogicalPlan] {
+  override def apply(plan: LogicalPlan): LogicalPlan = plan transformUp {
+    case table: UnresolvedInlineTable if table.expressionsResolved =>
+      validateInputDimension(table)
+      validateInputEvaluable(table)
+      convert(table)
+  }
+
+  /**
+   * Validates the input data dimension:
+   * 1. All rows have the same cardinality.
+   * 2. The number of column aliases defined is consistent with the number of columns in data.
+   *
+   * This is package visible for unit testing.
+   */
+  private[analysis] def validateInputDimension(table: UnresolvedInlineTable): Unit = {
+    if (table.rows.nonEmpty) {
+      val numCols = table.names.size
+      table.rows.zipWithIndex.foreach { case (row, ri) =>
+        if (row.size != numCols) {
+          table.failAnalysis(s"expected $numCols columns but found ${row.size} columns in row $ri")
+        }
+      }
+    }
+  }
+
+  /**
+   * Validates that all inline table data are valid expressions that can be evaluated
+   * (in this they must be foldable).
+   *
+   * This is package visible for unit testing.
+   */
+  private[analysis] def validateInputEvaluable(table: UnresolvedInlineTable): Unit = {
+    table.rows.foreach { row =>
+      row.foreach { e =>
+        // Note that nondeterministic expressions are not supported since they are not foldable.
+        if (!e.resolved || !e.foldable) {
+          e.failAnalysis(s"cannot evaluate expression ${e.sql} in inline table definition")
+        }
+      }
+    }
+  }
+
+  /**
+   * Convert a valid (with right shape and foldable inputs) [[UnresolvedInlineTable]]
+   * into a [[LocalRelation]].
+   *
+   * This function attempts to coerce inputs into consistent types.
+   *
+   * This is package visible for unit testing.
+   */
+  private[analysis] def convert(table: UnresolvedInlineTable): LocalRelation = {
+    // For each column, traverse all the values and find a common data type and nullability.
+    val fields = table.rows.transpose.zip(table.names).map { case (column, name) =>
+      val inputTypes = column.map(_.dataType)
+      val tpe = TypeCoercion.findWiderTypeWithoutStringPromotion(inputTypes).getOrElse {
+        table.failAnalysis(s"incompatible types found in column $name for inline table")
+      }
+      StructField(name, tpe, nullable = column.exists(_.nullable))
+    }
+    val attributes = StructType(fields).toAttributes
+    assert(fields.size == table.names.size)
+
+    val newRows: Seq[InternalRow] = table.rows.map { row =>
+      InternalRow.fromSeq(row.zipWithIndex.map { case (e, ci) =>
+        val targetType = fields(ci).dataType
+        try {
+          if (e.dataType.sameType(targetType)) {
+            e.eval()
+          } else {
+            Cast(e, targetType).eval()
+          }
+        } catch {
+          case NonFatal(ex) =>
+            table.failAnalysis(s"failed to evaluate expression ${e.sql}: ${ex.getMessage}")
+        }
+      })
+    }
+
+    LocalRelation(attributes, newRows)
+  }
+}
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala
index 21e96aaf53..193c3ec4e5 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala
@@ -150,7 +150,7 @@ object TypeCoercion {
    * [[findTightestCommonType]], but can handle decimal types. If the wider decimal type exceeds
    * system limitation, this rule will truncate the decimal type before return it.
    */
-  private def findWiderTypeWithoutStringPromotion(types: Seq[DataType]): Option[DataType] = {
+  def findWiderTypeWithoutStringPromotion(types: Seq[DataType]): Option[DataType] = {
     types.foldLeft[Option[DataType]](Some(NullType))((r, c) => r match {
       case Some(d) => findTightestCommonTypeOfTwo(d, c).orElse((d, c) match {
         case (t1: DecimalType, t2: DecimalType) =>
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/unresolved.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/unresolved.scala
index 3735a1501c..235ae04782 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/unresolved.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/unresolved.scala
@@ -50,10 +50,30 @@ case class UnresolvedRelation(
 }
 
 /**
- * Holds a table-valued function call that has yet to be resolved.
+ * An inline table that has not been resolved yet. Once resolved, it is turned by the analyzer into
+ * a [[org.apache.spark.sql.catalyst.plans.logical.LocalRelation]].
+ *
+ * @param names list of column names
+ * @param rows expressions for the data
+ */
+case class UnresolvedInlineTable(
+    names: Seq[String],
+    rows: Seq[Seq[Expression]])
+  extends LeafNode {
+
+  lazy val expressionsResolved: Boolean = rows.forall(_.forall(_.resolved))
+  override lazy val resolved = false
+  override def output: Seq[Attribute] = Nil
+}
+
+/**
+ * A table-valued function, e.g.
+ * {{{
+ *   select * from range(10);
+ * }}}
  */
-case class UnresolvedTableValuedFunction(
-    functionName: String, functionArgs: Seq[Expression]) extends LeafNode {
+case class UnresolvedTableValuedFunction(functionName: String, functionArgs: Seq[Expression])
+  extends LeafNode {
 
   override def output: Seq[Attribute] = Nil
 
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala
index 01322ae327..283e4d43ba 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala
@@ -670,39 +670,24 @@ class AstBuilder extends SqlBaseBaseVisitor[AnyRef] with Logging {
    */
   override def visitInlineTable(ctx: InlineTableContext): LogicalPlan = withOrigin(ctx) {
     // Get the backing expressions.
-    val expressions = ctx.expression.asScala.map { eCtx =>
-      val e = expression(eCtx)
-      validate(e.foldable, "All expressions in an inline table must be constants.", eCtx)
-      e
-    }
-
-    // Validate and evaluate the rows.
-    val (structType, structConstructor) = expressions.head.dataType match {
-      case st: StructType =>
-        (st, (e: Expression) => e)
-      case dt =>
-        val st = CreateStruct(Seq(expressions.head)).dataType
-        (st, (e: Expression) => CreateStruct(Seq(e)))
-    }
-    val rows = expressions.map {
-      case expression =>
-        val safe = Cast(structConstructor(expression), structType)
-        safe.eval().asInstanceOf[InternalRow]
+    val rows = ctx.expression.asScala.map { e =>
+      expression(e) match {
+        // inline table comes in two styles:
+        // style 1: values (1), (2), (3)  -- multiple columns are supported
+        // style 2: values 1, 2, 3  -- only a single column is supported here
+        case CreateStruct(children) => children  // style 1
+        case child => Seq(child)  // style 2
+      }
     }
 
-    // Construct attributes.
-    val baseAttributes = structType.toAttributes.map(_.withNullability(true))
-    val attributes = if (ctx.identifierList != null) {
-      val aliases = visitIdentifierList(ctx.identifierList)
-      validate(aliases.size == baseAttributes.size,
-        "Number of aliases must match the number of fields in an inline table.", ctx)
-      baseAttributes.zip(aliases).map(p => p._1.withName(p._2))
+    val aliases = if (ctx.identifierList != null) {
+      visitIdentifierList(ctx.identifierList)
     } else {
-      baseAttributes
+      Seq.tabulate(rows.head.size)(i => s"col${i + 1}")
     }
 
-    // Create plan and add an alias if a name has been defined.
-    LocalRelation(attributes, rows).optionalMap(ctx.identifier)(aliasPlan)
+    val table = UnresolvedInlineTable(aliases, rows)
+    table.optionalMap(ctx.identifier)(aliasPlan)
   }
 
   /**