Enable cell to call bool in graph

mindspore/python/mindspore/_extends/parse/standard_method.py

@@ -2302,7 +2302,11 @@ def bool_func(*data):
             return data != 0
         const_utils.raise_value_error("The truth value of an array with more than one element is ambiguous.")
     if not F.isconstant(data):
-        return len(data) != 0
+        if hasattr(data, "__bool__"):
+            return data.__bool__()
+        if hasattr(data, "__len__"):
+            return len(data) != 0
+        return True
     return cast_to_bool(data)
 
 

mindspore/python/mindspore/nn/cell.py

@@ -151,6 +151,9 @@ class Cell(Cell_):
         self.__dict__ = dict_
         self._attr_synced = False
 
+    def __bool__(self):
+        return True
+
     @property
     def _cell_tag(self):
         # `<class 'xxxxxxx'>` to `xxxxxxx`

mindspore/python/mindspore/nn/layer/container.py

@@ -233,6 +233,9 @@ class SequentialCell(Cell):
         self._cells = temp_dict
         self.cell_list = list(self._cells.values())
 
+    def __bool__(self):
+        return len(self._cells) != 0
+
     def __len__(self):
         return len(self._cells)
 
@@ -390,6 +393,9 @@ class CellList(_CellListBase, Cell):
             temp_dict[str(idx)] = cell
         self._cells = temp_dict
 
+    def __bool__(self):
+        return len(self._cells) != 0
+
     def __len__(self):
         return len(self._cells)
 

tests/ut/python/graph_syntax/python_builtin_functions/test_bool.py

@@ -15,8 +15,8 @@
 """ test graph fallback buildin python function bool"""
 import pytest
 import numpy as np
+import mindspore.nn as nn
 from mindspore import jit, context, Tensor
-
 context.set_context(mode=context.GRAPH_MODE)
 
 
@@ -199,3 +199,41 @@ def test_fallback_bool_with_input_tensor2():
         return bool(x)
 
     assert foo()
+
+
+class Net(nn.Cell):
+    def __init__(self):
+        super(Net, self).__init__()
+
+    def construct(self):
+        return 1
+
+
+def test_bool_for_cell_object():
+    """
+    Feature: Bool function.
+    Description: Test bool() for cell object input
+    Expectation: No exception.
+    """
+    @jit
+    def foo():
+        net = Net()
+        return bool(net)
+
+    assert foo()
+
+
+def test_bool_for_cell_object_2():
+    """
+    Feature: Bool function.
+    Description: Test bool() for cell object input
+    Expectation: No exception.
+    """
+    @jit
+    def foo():
+        net = Net()
+        if net:
+            return True
+        return False
+
+    assert foo()