From e5b1b33722b7329488e7550ab50b128999c095fd Mon Sep 17 00:00:00 2001
From: Gil Forsyth <gil@forsyth.dev>
Date: Mon, 30 Dec 2024 09:32:37 -0500
Subject: [PATCH] fix(dtypes): allow passing `nullable` kwarg to string parsed
 dtypes

---
 ibis/expr/datatypes/core.py             | 12 ++++++++----
 ibis/expr/datatypes/tests/test_parse.py |  5 +++--
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/ibis/expr/datatypes/core.py b/ibis/expr/datatypes/core.py
index f7c4324ceb1a..e66464663c73 100644
--- a/ibis/expr/datatypes/core.py
+++ b/ibis/expr/datatypes/core.py
@@ -73,8 +73,8 @@ def dtype(value: Any, nullable: bool = True) -> DataType:
 
 
 @dtype.register(str)
-def from_string(value):
-    return DataType.from_string(value)
+def from_string(value, nullable: bool = True):
+    return DataType.from_string(value, nullable)
 
 
 @dtype.register("numpy.dtype")
@@ -165,14 +165,18 @@ def castable(self, to, **kwargs) -> bool:
         return castable(self, to, **kwargs)
 
     @classmethod
-    def from_string(cls, value) -> Self:
+    def from_string(cls, value, nullable: bool = True) -> Self:
         from ibis.expr.datatypes.parse import parse
 
         try:
-            return parse(value)
+            typ = parse(value)
         except SyntaxError:
             raise TypeError(f"{value!r} cannot be parsed as a datatype")
 
+        if not nullable:
+            return typ.copy(nullable=nullable)
+        return typ
+
     @classmethod
     def from_typehint(cls, typ, nullable=True) -> Self:
         origin_type = get_origin(typ)
diff --git a/ibis/expr/datatypes/tests/test_parse.py b/ibis/expr/datatypes/tests/test_parse.py
index b332b9110511..fef021ba7cc0 100644
--- a/ibis/expr/datatypes/tests/test_parse.py
+++ b/ibis/expr/datatypes/tests/test_parse.py
@@ -13,6 +13,7 @@
 from ibis.common.annotations import ValidationError
 
 
+@pytest.mark.parametrize("nullable", [True, False])
 @pytest.mark.parametrize(
     ("spec", "expected"),
     [
@@ -43,8 +44,8 @@
         ("multipolygon", dt.multipolygon),
     ],
 )
-def test_primitive_from_string(spec, expected):
-    assert dt.dtype(spec) == expected
+def test_primitive_from_string(nullable, spec, expected):
+    assert dt.dtype(spec, nullable=nullable) == expected(nullable=nullable)
 
 
 @pytest.mark.parametrize(