Move view_roots to the only file where it is used

pytensor/graph/basic.py

@@ -1787,25 +1787,6 @@ def as_string(
     return [describe(output) for output in outputs]
 
 
-def view_roots(node: Variable) -> list[Variable]:
-    """Return the leaves from a search through consecutive view-maps."""
-    owner = node.owner
-    if owner is not None:
-        try:
-            vars_to_views = {owner.outputs[o]: i for o, i in owner.op.view_map.items()}
-        except AttributeError:
-            return [node]
-        if node in vars_to_views:
-            answer = []
-            for i in vars_to_views[node]:
-                answer += view_roots(owner.inputs[i])
-            return answer
-        else:
-            return [node]
-    else:
-        return [node]
-
-
 def apply_depends_on(apply: Apply, depends_on: Apply | Collection[Apply]) -> bool:
     """Determine if any `depends_on` is in the graph given by ``apply``.
 

pytensor/tensor/blas.py

@@ -85,7 +85,7 @@ from pathlib import Path
 import numpy as np
 from scipy.linalg import get_blas_funcs
 
-from pytensor.graph import vectorize_graph
+from pytensor.graph import Variable, vectorize_graph
 from pytensor.npy_2_compat import normalize_axis_tuple
 
 
@@ -97,7 +97,7 @@ except ImportError:
 
 import pytensor.scalar
 from pytensor.configdefaults import config
-from pytensor.graph.basic import Apply, view_roots
+from pytensor.graph.basic import Apply
 from pytensor.graph.op import Op
 from pytensor.graph.utils import InconsistencyError, MethodNotDefined, TestValueError
 from pytensor.link.c.op import COp
@@ -114,6 +114,25 @@ from pytensor.tensor.type import DenseTensorType, tensor
 _logger = logging.getLogger("pytensor.tensor.blas")
 
 
+def view_roots(node: Variable) -> list[Variable]:
+    """Return the leaves from a search through consecutive view-maps."""
+    owner = node.owner
+    if owner is not None:
+        try:
+            vars_to_views = {owner.outputs[o]: i for o, i in owner.op.view_map.items()}
+        except AttributeError:
+            return [node]
+        if node in vars_to_views:
+            answer = []
+            for i in vars_to_views[node]:
+                answer += view_roots(owner.inputs[i])
+            return answer
+        else:
+            return [node]
+    else:
+        return [node]
+
+
 def must_initialize_y_gemv():
     # Check whether Scipy GEMV could output nan if y in not initialized
     from scipy.linalg.blas import get_blas_funcs

tests/graph/test_basic.py

@@ -589,11 +589,6 @@ def test_io_connection_pattern():
     raise AssertionError()
 
 
-@pytest.mark.xfail(reason="Not implemented")
-def test_view_roots():
-    raise AssertionError()
-
-
 def test_get_var_by_name():
     r1, r2, r3 = MyVariable(1), MyVariable(2), MyVariable(3)
     o1 = MyOp(r1, r2)