[SPARK-9292] Analysis should check that join conditions' data types are BooleanType

This patch adds an analysis check to ensure that join conditions' data types are BooleanType. This check is necessary in order to report proper errors for non-boolean DataFrame join conditions.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #7630 from JoshRosen/SPARK-9292 and squashes the following commits:

aec6c7b [Josh Rosen] Check condition type in resolved()
75a3ea6 [Josh Rosen] Fix SPARK-9292.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/CheckAnalysis.scala

@@ -83,6 +83,11 @@ trait CheckAnalysis {
               s"filter expression '${f.condition.prettyString}' " +
                 s"of type ${f.condition.dataType.simpleString} is not a boolean.")
 
+          case j @ Join(_, _, _, Some(condition)) if condition.dataType != BooleanType =>
+            failAnalysis(
+              s"join condition '${condition.prettyString}' " +
+                s"of type ${condition.dataType.simpleString} is not a boolean.")
+
           case Aggregate(groupingExprs, aggregateExprs, child) =>
             def checkValidAggregateExpression(expr: Expression): Unit = expr match {
               case _: AggregateExpression => // OK

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/basicOperators.scala

@@ -128,7 +128,10 @@ case class Join(
 
   // Joins are only resolved if they don't introduce ambiguous expression ids.
   override lazy val resolved: Boolean = {
-    childrenResolved && expressions.forall(_.resolved) && selfJoinResolved
+    childrenResolved &&
+      expressions.forall(_.resolved) &&
+      selfJoinResolved &&
+      condition.forall(_.dataType == BooleanType)
   }
 }
 

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/AnalysisErrorSuite.scala

@@ -118,6 +118,11 @@ class AnalysisErrorSuite extends SparkFunSuite with BeforeAndAfter {
     testRelation.where(Literal(1)),
     "filter" :: "'1'" :: "not a boolean" :: Literal(1).dataType.simpleString :: Nil)
 
+  errorTest(
+    "non-boolean join conditions",
+    testRelation.join(testRelation, condition = Some(Literal(1))),
+    "condition" :: "'1'" :: "not a boolean" :: Literal(1).dataType.simpleString :: Nil)
+
   errorTest(
     "missing group by",
     testRelation2.groupBy('a)('b),