[SPARK-8573] [SPARK-8568] [SQL] [PYSPARK] raise Exception if column i…

…s used in booelan expression

It's a common mistake that user will put Column in a boolean expression (together with `and` , `or`), which does not work as expected, we should raise a exception in that case, and suggest user to use `&`, `|` instead.

Author: Davies Liu <davies@databricks.com>

Closes apache#6961 from davies/column_bool and squashes the following commits:

9f19beb [Davies Liu] update message
af74bd6 [Davies Liu] fix tests
07dff84 [Davies Liu] address comments, fix tests
f70c08e [Davies Liu] raise Exception if column is used in booelan expression

python/pyspark/sql/column.py

@@ -396,6 +396,11 @@ def over(self, window):
         jc = self._jc.over(window._jspec)
         return Column(jc)
 
+    def __nonzero__(self):
+        raise ValueError("Cannot convert column into bool: please use '&' for 'and', '|' for 'or', "
+                         "'~' for 'not' when building DataFrame boolean expressions.")
+    __bool__ = __nonzero__
+
     def __repr__(self):
         return 'Column<%s>' % self._jc.toString().encode('utf8')
 

python/pyspark/sql/tests.py

@@ -164,6 +164,14 @@ def test_explode(self):
         self.assertEqual(result[0][0], "a")
         self.assertEqual(result[0][1], "b")
 
+    def test_and_in_expression(self):
+        self.assertEqual(4, self.df.filter((self.df.key <= 10) & (self.df.value <= "2")).count())
+        self.assertRaises(ValueError, lambda: (self.df.key <= 10) and (self.df.value <= "2"))
+        self.assertEqual(14, self.df.filter((self.df.key <= 3) | (self.df.value < "2")).count())
+        self.assertRaises(ValueError, lambda: self.df.key <= 3 or self.df.value < "2")
+        self.assertEqual(99, self.df.filter(~(self.df.key == 1)).count())
+        self.assertRaises(ValueError, lambda: not self.df.key == 1)
+
     def test_udf_with_callable(self):
         d = [Row(number=i, squared=i**2) for i in range(10)]
         rdd = self.sc.parallelize(d)
@@ -408,7 +416,7 @@ def test_column_operators(self):
         self.assertTrue(isinstance((- ci - 1 - 2) % 3 * 2.5 / 3.5, Column))
         rcc = (1 + ci), (1 - ci), (1 * ci), (1 / ci), (1 % ci)
         self.assertTrue(all(isinstance(c, Column) for c in rcc))
-        cb = [ci == 5, ci != 0, ci > 3, ci < 4, ci >= 0, ci <= 7, ci and cs, ci or cs]
+        cb = [ci == 5, ci != 0, ci > 3, ci < 4, ci >= 0, ci <= 7]
         self.assertTrue(all(isinstance(c, Column) for c in cb))
         cbool = (ci & ci), (ci | ci), (~ci)
         self.assertTrue(all(isinstance(c, Column) for c in cbool))