SNOW-1348700 Fix index issues in handling of CaseExpr, IsNull, IsNotN…

…ull and Like expressions (#1704)

CHANGELOG.md

@@ -27,7 +27,9 @@
 - Fixed a bug in convert_timezone that made the setting the source_timezone parameter return an error.
 - Fixed a bug where creating DataFrame with empty data of type `DateType` raises `AttributeError`.
 - Fixed a bug that table merge fails when update clause exists but no update takes place.
-- Fixed a bug in mock implementation of `to_char` that raises `IndexError` when incoming column has inconsecutive row index.
+- Fixed a bug in mock implementation of `to_char` that raises `IndexError` when incoming column has nonconsecutive row index.
+- Fixed a bug in handling of `CaseExpr` expressions that raises `IndexError` when incoming column has nonconsecutive row index.
+- Fixed a bug in implementation of `Column.like` that raises `IndexError` when incoming column has nonconsecutive row index.
 
 #### Improvements
 

src/snowflake/snowpark/mock/_plan.py

@@ -1643,18 +1643,16 @@ def calculate_expression(
         child_column = calculate_expression(
             exp.child, input_data, analyzer, expr_to_alias
         )
-        return ColumnEmulator(
-            data=[bool(data is None) for data in child_column],
-            sf_type=ColumnType(BooleanType(), True),
-        )
+        res = child_column.apply(lambda x: bool(x is None))
+        res.sf_type = ColumnType(BooleanType(), True)
+        return res
     if isinstance(exp, IsNotNull):
         child_column = calculate_expression(
             exp.child, input_data, analyzer, expr_to_alias
         )
-        return ColumnEmulator(
-            data=[bool(data is not None) for data in child_column],
-            sf_type=ColumnType(BooleanType(), True),
-        )
+        res = child_column.apply(lambda x: bool(x is not None))
+        res.sf_type = ColumnType(BooleanType(), True)
+        return res
     if isinstance(exp, IsNaN):
         child_column = calculate_expression(
             exp.child, input_data, analyzer, expr_to_alias
@@ -1813,11 +1811,12 @@ def _match_pattern(row) -> bool:
         return result
     if isinstance(exp, Like):
         lhs = calculate_expression(exp.expr, input_data, analyzer, expr_to_alias)
+
         pattern = convert_wildcard_to_regex(
             str(
-                calculate_expression(exp.pattern, input_data, analyzer, expr_to_alias)[
-                    0
-                ]
+                calculate_expression(
+                    exp.pattern, input_data, analyzer, expr_to_alias
+                ).iloc[0]
             )
         )
         result = lhs.str.match(pattern)
@@ -1868,8 +1867,7 @@ def _match_pattern(row) -> bool:
         return res
     if isinstance(exp, CaseWhen):
         remaining = input_data
-        output_data = ColumnEmulator([None] * len(input_data))
-        output_data.sf_type = None
+        output_data = ColumnEmulator([None] * len(input_data), index=input_data.index)
         for case in exp.branches:
             condition = calculate_expression(
                 case[0], input_data, analyzer, expr_to_alias

tests/mock/test_column.py

@@ -0,0 +1,20 @@
+#
+# Copyright (c) 2012-2024 Snowflake Computing Inc. All rights reserved.
+#
+
+from snowflake.snowpark.functions import col, when
+from snowflake.snowpark.row import Row
+
+
+def test_casewhen_with_non_zero_row_index(session):
+    df = session.create_dataframe([[1, 2], [3, 4]], schema=["a", "b"])
+    assert df.filter(col("a") > 1).select(
+        when(col("a").is_null(), 5).when(col("a") == 1, 6).otherwise(7).as_("a")
+    ).collect() == [Row(A=7)]
+
+
+def test_like_with_non_zero_row_index(session):
+    df = session.create_dataframe([["1", 2], ["3", 4]], schema=["a", "b"])
+    assert df.filter(col("b") > 2).select(
+        col("a").like("1").alias("res")
+    ).collect() == [Row(RES=False)]