Avoid recursion error if filter condition can optimize itself (#821)

dask_expr/_expr.py

@@ -1183,6 +1183,9 @@ class Elemwise(Blockwise):
 
     def _simplify_up(self, parent, dependents):
         if self._filter_passthrough and isinstance(parent, Filter):
+            if self._name != parent.frame._name:
+                # We can't push the filter through the filter condition
+                return
             parents = [x() for x in dependents[self._name] if x() is not None]
             if not all(isinstance(p, Filter) for p in parents):
                 return

dask_expr/tests/test_collection.py

@@ -2293,3 +2293,11 @@ def test_axes(df, pdf):
     [assert_eq(d, p) for d, p in zip(df.axes, pdf.axes)]
     assert len(df.x.axes) == len(pdf.x.axes)
     assert_eq(df.x.axes[0], pdf.x.axes[0])
+
+
+def test_filter_optimize_condition():
+    pdf = pd.DataFrame({"a": [1, 2, 3, 4], "b": [True, False, True, False]})
+    df = from_pandas(pdf, npartitions=2)
+    result = df[df.b.fillna(True)]
+    expected = pdf[pdf.b.fillna(True)]
+    assert_eq(result, expected)