Fix nullability of Substring expression.

tdas · Jul 16, 2014 · 80958ac · 80958ac
1 parent 4576d80
commit 80958ac
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Showing 2 changed files with 9 additions and 2 deletions.
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringOperations.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringOperations.scala
@@ -215,8 +215,8 @@ case class EndsWith(left: Expression, right: Expression)
 case class Substring(str: Expression, pos: Expression, len: Expression) extends Expression {
 
   type EvaluatedType = Any
-  
-  def nullable: Boolean = true
+
+  def nullable: Boolean = str.nullable || pos.nullable || len.nullable
   def dataType: DataType = {
     if (!resolved) {
       throw new UnresolvedException(this, s"Cannot resolve since $children are not resolved")

diff --git a/.../src/test/scala/org/apache/spark/sql/catalyst/expressions/ExpressionEvaluationSuite.scala b/.../src/test/scala/org/apache/spark/sql/catalyst/expressions/ExpressionEvaluationSuite.scala
@@ -514,6 +514,13 @@ class ExpressionEvaluationSuite extends FunSuite {
 
     // 2-arg substring from nonzero position
     checkEvaluation(Substring(s, Literal(2, IntegerType), Literal(Integer.MAX_VALUE, IntegerType)), "xample", row)
+
+    val s_notNull = 'a.string.notNull.at(0)
+
+    assert(Substring(s, Literal(0, IntegerType), Literal(2, IntegerType)).nullable === true)
+    assert(Substring(s_notNull, Literal(0, IntegerType), Literal(2, IntegerType)).nullable === false)
+    assert(Substring(s_notNull, Literal(null, IntegerType), Literal(2, IntegerType)).nullable === true)
+    assert(Substring(s_notNull, Literal(0, IntegerType), Literal(null, IntegerType)).nullable === true)
   }
 }