fix the div 0 error of deform_conv2d (PaddlePaddle#49962)

python/paddle/fluid/tests/unittests/test_deformable_conv_op.py

@@ -441,6 +441,23 @@ def test_invalid_filter():
 
         self.assertRaises(ValueError, test_invalid_filter)
 
+        def test_invalid_groups():
+            paddle.enable_static()
+            input = paddle.static.data(
+                name='input_groups', shape=[1, 1, 1, 1], dtype='float32'
+            )
+            offset = paddle.static.data(
+                name='offset_groups', shape=[1, 1], dtype='float32'
+            )
+            mask = paddle.static.data(
+                name='mask_groups', shape=[1], dtype='float32'
+            )
+            paddle.static.nn.deform_conv2d(
+                input, offset, mask, 1, 1, padding=1, groups=0
+            )
+
+        self.assertRaises(ValueError, test_invalid_groups)
+
 
 class TestDeformConv2DAPI(unittest.TestCase):
     def test_api(self):

python/paddle/static/nn/common.py

@@ -2255,6 +2255,8 @@ def deformable_conv(
     if groups is None:
         num_filter_channels = num_channels
     else:
+        if groups == 0:
+            raise ValueError("groups should not be 0.")
         if num_channels % groups != 0:
             raise ValueError("num_channels must be divisible by groups.")
         num_filter_channels = num_channels // groups