Merge pull request #161 from dourvaris/fix/empty-nested-array

Fix issue when row contains an empty nested array
mymarilyn · Aug 14, 2020 · 7c6cd15 · 7c6cd15
2 parents d80c330 + 503bbc4
commit 7c6cd15
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Showing 2 changed files with 23 additions and 4 deletions.
diff --git a/clickhouse_driver/columns/arraycolumn.py b/clickhouse_driver/columns/arraycolumn.py
@@ -172,10 +172,11 @@ def _read(self, size, buf):
             else:
                 prev_offset += size
 
-        data = nested_column._read_data(
-            nested_column_size, buf,
-            nulls_map=nulls_map
-        )
+        data = []
+        if nested_column_size:
+            data = nested_column._read_data(
+                nested_column_size, buf, nulls_map=nulls_map
+            )
 
         # Build nested tuple structure.
         for slices, nulls_map in reversed(slices_series):

diff --git a/tests/columns/test_array.py b/tests/columns/test_array.py
@@ -105,6 +105,24 @@ def test_nested_of_nested(self):
             inserted = self.client.execute(query)
             self.assertEqual(inserted, data)
 
+    def test_empty_nested(self):
+        columns = "a Array(Array(Array(Int32))), b Array(Array(Array(Int32)))"
+        data = [
+            ([], [[]],),
+        ]
+
+        with self.create_table(columns):
+            self.client.execute("INSERT INTO test (a, b) VALUES", data)
+
+            query = "SELECT * FROM test"
+            inserted = self.emit_cli(query)
+            self.assertEqual(
+                inserted, "[]\t[[]]\n",
+            )
+
+            inserted = self.client.execute(query)
+            self.assertEqual(inserted, data)
+
     def test_type_mismatch_error(self):
         columns = 'a Array(Int32)'
         data = [('test', )]