From 711bf9f973546a4074ee29d0d491067bdf9271b3 Mon Sep 17 00:00:00 2001
From: Jim Crist-Harif <jcristharif@gmail.com>
Date: Mon, 6 May 2024 08:29:58 -0500
Subject: [PATCH] fix(api): treat `col == None` or `col == ibis.NA` as
 `col.isnull()` (#9114)

Co-authored-by: Phillip Cloud <417981+cpcloud@users.noreply.github.com>
---
 ibis/expr/types/core.py             | 10 ++++++++++
 ibis/expr/types/generic.py          | 14 +++++++++-----
 ibis/tests/expr/test_value_exprs.py | 12 ++++++++++++
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/ibis/expr/types/core.py b/ibis/expr/types/core.py
index 1ab39d9d0725..a7fd748af5fd 100644
--- a/ibis/expr/types/core.py
+++ b/ibis/expr/types/core.py
@@ -737,3 +737,13 @@ def _binop(op_class: type[ops.Binary], left: ir.Value, right: ir.Value) -> ir.Va
         return NotImplemented
     else:
         return node.to_expr()
+
+
+def _is_null_literal(value: Any) -> bool:
+    """Detect whether `value` will be treated by ibis as a null literal."""
+    if value is None:
+        return True
+    if isinstance(value, Expr):
+        op = value.op()
+        return isinstance(op, ops.Literal) and op.value is None
+    return False
diff --git a/ibis/expr/types/generic.py b/ibis/expr/types/generic.py
index 4a554e17c273..367d6031a62e 100644
--- a/ibis/expr/types/generic.py
+++ b/ibis/expr/types/generic.py
@@ -13,7 +13,7 @@
 from ibis.common.deferred import Deferred, _, deferrable
 from ibis.common.grounds import Singleton
 from ibis.expr.rewrites import rewrite_window_input
-from ibis.expr.types.core import Expr, _binop, _FixedTextJupyterMixin
+from ibis.expr.types.core import Expr, _binop, _FixedTextJupyterMixin, _is_null_literal
 from ibis.expr.types.pretty import to_rich
 from ibis.util import deprecated, warn_deprecated
 
@@ -1160,13 +1160,17 @@ def __hash__(self) -> int:
         return super().__hash__()
 
     def __eq__(self, other: Value) -> ir.BooleanValue:
-        if other is None:
-            return _binop(ops.IdenticalTo, self, other)
+        if _is_null_literal(other):
+            return self.isnull()
+        elif _is_null_literal(self):
+            return other.isnull()
         return _binop(ops.Equals, self, other)
 
     def __ne__(self, other: Value) -> ir.BooleanValue:
-        if other is None:
-            return ~self.__eq__(other)
+        if _is_null_literal(other):
+            return self.notnull()
+        elif _is_null_literal(self):
+            return other.notnull()
         return _binop(ops.NotEquals, self, other)
 
     def __ge__(self, other: Value) -> ir.BooleanValue:
diff --git a/ibis/tests/expr/test_value_exprs.py b/ibis/tests/expr/test_value_exprs.py
index 5ded2434bfbf..ec8e3a224750 100644
--- a/ibis/tests/expr/test_value_exprs.py
+++ b/ibis/tests/expr/test_value_exprs.py
@@ -350,6 +350,18 @@ def test_notnull(table):
     assert isinstance(expr.op(), ops.NotNull)
 
 
+@pytest.mark.parametrize(
+    "value",
+    [None, ibis.NA, ibis.literal(None, type="int32")],
+    ids=["none", "NA", "typed-null"],
+)
+def test_null_eq_and_ne(table, value):
+    assert (table.a == value).equals(table.a.isnull())
+    assert (value == table.a).equals(table.a.isnull())
+    assert (table.a != value).equals(table.a.notnull())
+    assert (value != table.a).equals(table.a.notnull())
+
+
 @pytest.mark.parametrize("column", ["e", "f"], ids=["float32", "double"])
 def test_isnan_isinf_column(table, column):
     expr = table[column].isnan()