[GLCC]Part-4: fix testcases for dy2st PyLayer (PaddlePaddle#57633)

* add testcase load_inference_model

* polish code for last pr

* delete annots

* fix docs of static_pylayer

python/paddle/static/nn/static_pylayer.py

@@ -242,14 +242,14 @@ def static_pylayer(forward_fn, inputs, backward_fn=None, name=None):
     the logic of ``forward_fn`` and ``backward_fn``, with the operator ``pylayer``
     holding information about the two blocks.
 
-    ``forward_fn`` and ``backward_fn`` should return a nest structure of tensors.
-    A nest structure of tensors in PaddlePaddle is tensor(s), or tuple of tensors, or
-    list of tensors.
+    ``forward_fn`` and ``backward_fn`` should return a nest structure of Variables.
+    A nest structure of Variables in PaddlePaddle is Variable(s), or tuple of Variables, or
+    list of Variables.
 
     Note:
-        1. If ``backward_fn`` is not None, user needs to keep the number of inputs to ``forward_fn`` the same as the
-        number of outputs to ``backward_fn``, and the number of outputs to ``forward_fn``
-        the same as the number of inputs to ``backward_fn``.
+        1. If ``backward_fn`` is not None, user needs to keep the number of `Variable` inputs to ``forward_fn`` the same as the
+        number of `Variable` outputs to ``backward_fn``, and the number of `Variable` outputs to ``forward_fn``
+        the same as the number of `Variable` inputs to ``backward_fn``.
 
         2. If ``backward_fn`` is None, ``stop_gradient`` attr of all Variable in ``inputs`` is expected to be True.
         Otherwise it might get unexpected results in backward propagation.

test/dygraph_to_static/test_pylayer.py

@@ -243,7 +243,7 @@ def __init__(self, in_size, out_size):
     def forward(self, x1, x2):
         y1 = self.linear1(x1)
         y2 = self.linear1(x2)
-        out = cus_tanh_2.apply(y1, func1=paddle.tanh)
+        out = cus_tanh_2.apply(y1, paddle.tanh)
         out = out + y2
         out = paddle.mean(out)
         return out

test/dygraph_to_static/test_save_inference_model.py

@@ -21,6 +21,7 @@
 
 import paddle
 from paddle import base
+from paddle.autograd import PyLayer
 from paddle.jit.api import to_static
 from paddle.jit.dy2static.partial_program import partial_program_from
 from paddle.jit.translated_layer import INFER_MODEL_SUFFIX, INFER_PARAMS_SUFFIX
@@ -45,6 +46,33 @@ def forward(self, x):
         return out, y
 
 
+class cus_tanh(PyLayer):
+    @staticmethod
+    def forward(ctx, x):
+        y = paddle.tanh(x)
+        ctx.save_for_backward(y)
+        return y
+
+    @staticmethod
+    def backward(ctx, dy):
+        (y,) = ctx.saved_tensor()
+        grad = dy * (1 - paddle.square(y))
+        return grad
+
+
+class SimplePyLayerNet(paddle.nn.Layer):
+    def __init__(self, fc_size):
+        super().__init__()
+        self._linear = paddle.nn.Linear(fc_size, fc_size)
+
+    @to_static
+    def forward(self, x):
+        y = self._linear(x)
+        out = cus_tanh.apply(y)
+        loss = paddle.mean(out)
+        return loss, out
+
+
 class TestDyToStaticSaveInferenceModel(unittest.TestCase):
     def setUp(self):
         self.temp_dir = tempfile.TemporaryDirectory()
@@ -94,8 +122,52 @@ def test_save_inference_model(self):
             layer, [x_data], dygraph_out.numpy(), feed=[x]
         )
 
+    @ast_only_test
+    def test_save_pylayer_model(self):
+        fc_size = 20
+        x_data = np.random.random((fc_size, fc_size)).astype('float32')
+        paddle.base.framework._set_expected_place(place)
+
+        base.default_startup_program().random_seed = SEED
+        base.default_main_program().random_seed = SEED
+        paddle.disable_static()
+        x = base.dygraph.to_variable(x_data)
+        layer = SimplePyLayerNet(fc_size)
+        adam = paddle.optimizer.SGD(
+            learning_rate=0.1, parameters=layer.parameters()
+        )
+
+        for i in range(5):
+            loss, pred = layer(x)
+            loss.backward()
+            adam.minimize(loss)
+            layer.clear_gradients()
+
+        infer_model_prefix = os.path.join(
+            self.temp_dir.name, "test_dy2stat_inference_in_guard/model_pylayer"
+        )
+        paddle.jit.save(
+            layer=layer,
+            path=infer_model_prefix,
+            input_spec=[x],
+            output_spec=[pred],
+        )
+        # Check the correctness of the inference
+        loss_out, _ = layer(x)
+
+        loss_out_numpy = float(loss_out)
+        self.check_save_inference_model(
+            layer, [x_data], loss_out_numpy, enable_new_ir=False
+        )
+        self.check_save_inference_model(
+            layer, [x_data], loss_out_numpy, fetch=[loss], enable_new_ir=False
+        )
+        self.check_save_inference_model(
+            layer, [x_data], loss_out_numpy, feed=[x], enable_new_ir=False
+        )
+
     def check_save_inference_model(
-        self, model, inputs, gt_out, feed=None, fetch=None
+        self, model, inputs, gt_out, feed=None, fetch=None, enable_new_ir=True
     ):
         expected_persistable_vars = {p.name for p in model.parameters()}
 
@@ -113,13 +185,20 @@ def check_save_inference_model(
             input_spec=feed if feed else None,
             output_spec=fetch if fetch else None,
         )
-        # Check the correctness of the inference
-        infer_out = self.load_and_run_inference(
-            infer_model_dir, model_filename, params_filename, inputs
-        )
+        if enable_new_ir:
+            wrapped_load_and_run_inference = test_and_compare_with_new_ir(True)(
+                self.load_and_run_inference
+            )
+            infer_out = wrapped_load_and_run_inference(
+                infer_model_dir, model_filename, params_filename, inputs
+            )
+        else:
+            infer_out = self.load_and_run_inference(
+                infer_model_dir, model_filename, params_filename, inputs
+            )
+
         np.testing.assert_allclose(gt_out, infer_out, rtol=1e-05)
 
-    @test_and_compare_with_new_ir(True)
     def load_and_run_inference(
         self, model_path, model_filename, params_filename, inputs
     ):

test/legacy_test/test_prune.py

@@ -211,7 +211,7 @@ def _mock_guard(mock):
     base.Executor._prune_program = original
 
 
-def net1():
+def create_net1():
     x = paddle.static.data(name='x', shape=[-1, 2], dtype='float32')
     x.desc.set_need_check_feed(False)
     label = paddle.static.data(name="label", shape=[-1, 1], dtype="int64")
@@ -238,7 +238,7 @@ def net1():
     return x, y, label, loss1, loss2, w_param_attrs
 
 
-def net2():
+def create_net2():
     x1 = paddle.static.data(name='x1', shape=[-1, 2], dtype='float32')
     x1.desc.set_need_check_feed(False)
     x2 = paddle.static.data(name='x2', shape=[-1, 2], dtype='float32')
@@ -286,8 +286,8 @@ def net2():
 
 class TestExecutorRunAutoPrune(unittest.TestCase):
     def setUp(self):
-        self.net1 = net1
-        self.net2 = net2
+        self.net1 = create_net1
+        self.net2 = create_net2
 
     def test_not_prune(self):
         """