From 1caf6dea3bafc6cc100cb10936db75546cf0d87e Mon Sep 17 00:00:00 2001
From: Mark Needham <m.h.needham@gmail.com>
Date: Thu, 29 Feb 2024 16:36:45 +0000
Subject: [PATCH] fix(clickhouse): make arrays non nullable (#8501)

---
 .../clickhouse/tests/test_datatypes.py        | 19 ++++++++++++++++++-
 ibis/backends/sql/datatypes.py                |  2 +-
 ibis/backends/tests/test_array.py             |  8 ++++----
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/ibis/backends/clickhouse/tests/test_datatypes.py b/ibis/backends/clickhouse/tests/test_datatypes.py
index ae85290cde98..b784ceb224ef 100644
--- a/ibis/backends/clickhouse/tests/test_datatypes.py
+++ b/ibis/backends/clickhouse/tests/test_datatypes.py
@@ -3,6 +3,7 @@
 import hypothesis as h
 import hypothesis.strategies as st
 import pytest
+import sqlglot.expressions as sge
 from pytest import param
 
 import ibis
@@ -278,7 +279,7 @@ def test_parse_type(ch_type, ibis_type):
         | its.date_dtype()
         | its.time_dtype()
         | its.timestamp_dtype(scale=st.integers(0, 9))
-        | its.array_dtypes(roundtrippable_types)
+        | its.array_dtypes(roundtrippable_types, nullable=false)
         | its.map_dtypes(map_key_types, roundtrippable_types, nullable=false)
     )
 )
@@ -289,3 +290,19 @@ def test_type_roundtrip(ibis_type):
     type_string = ClickHouseType.to_string(ibis_type)
     parsed_ibis_type = ClickHouseType.from_string(type_string)
     assert parsed_ibis_type == ibis_type
+
+
+def test_arrays_nullable():
+    # if dtype.nullable and not (dtype.is_map() or dtype.is_array()):
+    sge_type = ClickHouseType.from_ibis(dt.Array("float"))
+    typecode = sge.DataType.Type
+
+    assert sge_type == sge.DataType(
+        this=typecode.ARRAY,
+        expressions=[
+            sge.DataType(
+                this=typecode.NULLABLE, expressions=[sge.DataType(this=typecode.DOUBLE)]
+            )
+        ],
+        nested=True,
+    )
diff --git a/ibis/backends/sql/datatypes.py b/ibis/backends/sql/datatypes.py
index 9fe2f6f72ef9..6b8687513849 100644
--- a/ibis/backends/sql/datatypes.py
+++ b/ibis/backends/sql/datatypes.py
@@ -966,7 +966,7 @@ class ClickHouseType(SqlglotType):
     def from_ibis(cls, dtype: dt.DataType) -> sge.DataType:
         """Convert a sqlglot type to an ibis type."""
         typ = super().from_ibis(dtype)
-        if dtype.nullable and not dtype.is_map():
+        if dtype.nullable and not (dtype.is_map() or dtype.is_array()):
             # map cannot be nullable in clickhouse
             return sge.DataType(this=typecode.NULLABLE, expressions=[typ])
         else:
diff --git a/ibis/backends/tests/test_array.py b/ibis/backends/tests/test_array.py
index 584c4ac3e60f..156c31bda8d5 100644
--- a/ibis/backends/tests/test_array.py
+++ b/ibis/backends/tests/test_array.py
@@ -938,8 +938,8 @@ def flatten_data():
             marks=[
                 pytest.mark.notyet(
                     ["clickhouse"],
-                    reason="doesn't support nullable array elements",
-                    raises=ClickHouseDatabaseError,
+                    reason="Arrays are never nullable",
+                    raises=AssertionError,
                 )
             ],
         ),
@@ -950,8 +950,8 @@ def flatten_data():
             marks=[
                 pytest.mark.notyet(
                     ["clickhouse"],
-                    reason="doesn't support nullable array elements",
-                    raises=ClickHouseDatabaseError,
+                    reason="Arrays are never nullable",
+                    raises=AssertionError,
                 )
             ],
         ),