[SPARK-12624][PYSPARK] Checks row length when converting Java arrays …

…to Python rows

When actual row length doesn't conform to specified schema field length, we should give a better error message instead of throwing an unintuitive `ArrayOutOfBoundsException`.

Author: Cheng Lian <lian@databricks.com>

Closes #10886 from liancheng/spark-12624.

(cherry picked from commit 3327fd2)
Signed-off-by: Yin Huai <yhuai@databricks.com>

python/pyspark/sql/tests.py

@@ -364,6 +364,15 @@ def test_infer_schema_to_local(self):
         df3 = self.sqlCtx.createDataFrame(rdd, df.schema)
         self.assertEqual(10, df3.count())
 
+    def test_create_dataframe_schema_mismatch(self):
+        input = [Row(a=1)]
+        rdd = self.sc.parallelize(range(3)).map(lambda i: Row(a=i))
+        schema = StructType([StructField("a", IntegerType()), StructField("b", StringType())])
+        df = self.sqlCtx.createDataFrame(rdd, schema)
+        message = ".*Input row doesn't have expected number of values required by the schema.*"
+        with self.assertRaisesRegexp(Exception, message):
+            df.show()
+
     def test_serialize_nested_array_and_map(self):
         d = [Row(l=[Row(a=1, b='s')], d={"key": Row(c=1.0, d="2")})]
         rdd = self.sc.parallelize(d)

sql/core/src/main/scala/org/apache/spark/sql/execution/python.scala

@@ -220,7 +220,14 @@ object EvaluatePython {
       ArrayBasedMapData(keys, values)
 
     case (c, StructType(fields)) if c.getClass.isArray =>
-      new GenericInternalRow(c.asInstanceOf[Array[_]].zip(fields).map {
+      val array = c.asInstanceOf[Array[_]]
+      if (array.length != fields.length) {
+        throw new IllegalStateException(
+          s"Input row doesn't have expected number of values required by the schema. " +
+          s"${fields.length} fields are required while ${array.length} values are provided."
+        )
+      }
+      new GenericInternalRow(array.zip(fields).map {
         case (e, f) => fromJava(e, f.dataType)
       })