fix loaded no params layer run error (#27241)

paddle/fluid/operators/run_program_op.cc

@@ -27,9 +27,6 @@ class RunProgramOp : public framework::OperatorWithKernel {
     PADDLE_ENFORCE_EQ(ctx->HasInputs("X"), true,
                       platform::errors::NotFound(
                           "Input(X) of RunProgramOp should not be null."));
-    PADDLE_ENFORCE_EQ(ctx->HasInputs("Params"), true,
-                      platform::errors::NotFound(
-                          "Input(Params) of RunProgramOp should not be null."));
     PADDLE_ENFORCE_EQ(ctx->HasOutputs("Out"), true,
                       platform::errors::NotFound(
                           "Output(Out) of RunProgramOp should not be null."));
@@ -73,7 +70,8 @@ class RunProgramOpMaker : public framework::OpProtoAndCheckerMaker {
              "(vector<LoDTensor or SelecetedRows>)"
              "The input parameter of RunProgram operator, also the parameters "
              "of the loaded program.")
-        .AsDuplicable();
+        .AsDuplicable()
+        .AsDispensable();
     AddOutput("Out",
               "(vector<LoDTensor>)"
               "The output tensors of RunProgram operator, also the fetch "
@@ -121,10 +119,6 @@ class RunProgramGradOp : public framework::OperatorWithKernel {
     PADDLE_ENFORCE_EQ(ctx->HasInputs("X"), true,
                       platform::errors::NotFound(
                           "Input(X) of RunProgramGradOp should not be null."));
-    PADDLE_ENFORCE_EQ(
-        ctx->HasInputs("Params"), true,
-        platform::errors::NotFound(
-            "Input(Params) of RunProgramGradOp should not be null."));
     PADDLE_ENFORCE_EQ(
         ctx->HasInputs(framework::GradVarName("Out")), true,
         platform::errors::NotFound(

paddle/fluid/operators/run_program_op.h

@@ -209,9 +209,14 @@ class RunProgramOpKernel : public framework::OpKernel<T> {
     auto output_vars = ctx.MultiOutputVar("Out");
 
     auto input_var_names = ctx.InputNames("X");
-    auto param_names = ctx.InputNames("Params");
     auto output_var_names = ctx.OutputNames("Out");
 
+    // current program may not hold parameters
+    std::vector<std::string> param_names;
+    if (!param_vars.empty()) {
+      param_names = ctx.InputNames("Params");
+    }
+
     auto *block = ctx.Attr<BlockDesc *>("global_block");
     auto *program = block->Program();
     auto start_op_index = ctx.Attr<int64_t>("start_op_index");

python/paddle/fluid/dygraph/io.py

@@ -479,6 +479,10 @@ def _load_persistable_vars(model_path,
             var_file_path = os.path.join(model_path, params_filename)
         else:
             var_file_path = os.path.join(model_path, VARIABLE_FILENAME)
+        if not os.path.exists(var_file_path):
+            if len(extra_var_info) != 0:
+                raise ValueError("The model to be loaded is incomplete.")
+        else:
             framework._dygraph_tracer().trace_op(
                 type='load_combine',
                 inputs={},

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

@@ -23,7 +23,7 @@ from paddle.static import InputSpec
 import paddle.fluid as fluid
 from paddle.fluid.dygraph import Linear
 from paddle.fluid.dygraph import declarative, ProgramTranslator
-from paddle.fluid.dygraph.io import EXTRA_VAR_INFO_FILENAME
+from paddle.fluid.dygraph.io import EXTRA_VAR_INFO_FILENAME, VARIABLE_FILENAME
 
 BATCH_SIZE = 32
 BATCH_NUM = 10
@@ -153,6 +153,24 @@ class LinearNetReturnHidden(fluid.dygraph.Layer):
         return y, loss
 
 
+class EmptyLayer(paddle.nn.Layer):
+    def __init__(self):
+        super(EmptyLayer, self).__init__()
+
+    @paddle.jit.to_static
+    def forward(self, x):
+        return x
+
+
+class NoParamLayer(paddle.nn.Layer):
+    def __init__(self):
+        super(NoParamLayer, self).__init__()
+
+    @paddle.jit.to_static
+    def forward(self, x, y):
+        return x + y
+
+
 def train(layer, input_size=784, label_size=1):
     # create optimizer
     sgd = fluid.optimizer.SGDOptimizer(
@@ -273,6 +291,15 @@ class TestJitSaveLoad(unittest.TestCase):
         with self.assertRaises(ValueError):
             model_dict, _ = fluid.dygraph.load_dygraph(model_path)
 
+    def test_jit_load_model_incomplete(self):
+        model_path = "model.test_jit_save_load.remove_variables"
+        self.train_and_save_model(model_path=model_path)
+        # remove `__variables__`	
+        var_path = os.path.join(model_path, VARIABLE_FILENAME)
+        os.remove(var_path)
+        with self.assertRaises(ValueError):
+            paddle.jit.load(model_path)
+
 
 class TestSaveLoadWithInputSpec(unittest.TestCase):
     def setUp(self):
@@ -695,5 +722,38 @@ class TestJitSaveMultiCases(unittest.TestCase):
                 configs=configs)
 
 
+class TestJitSaveLoadEmptyLayer(unittest.TestCase):
+    def setUp(self):
+        self.model_path = "model.jit_save_load_empty_layer"
+        # enable dygraph mode
+        paddle.disable_static()
+
+    def test_save_load_empty_layer(self):
+        layer = EmptyLayer()
+        x = paddle.to_variable(np.random.random((10)).astype('float32'))
+        out = layer(x)
+        paddle.jit.save(layer, self.model_path)
+        load_layer = paddle.jit.load(self.model_path)
+        load_out = load_layer(x)
+        self.assertTrue(np.array_equal(out, load_out))
+
+
+class TestJitSaveLoadNoParamLayer(unittest.TestCase):
+    def setUp(self):
+        self.model_path = "model.jit_save_load_no_param_layer"
+        # enable dygraph mode
+        paddle.disable_static()
+
+    def test_save_load_no_param_layer(self):
+        layer = NoParamLayer()
+        x = paddle.to_variable(np.random.random((5)).astype('float32'))
+        y = paddle.to_variable(np.random.random((5)).astype('float32'))
+        out = layer(x, y)
+        paddle.jit.save(layer, self.model_path)
+        load_layer = paddle.jit.load(self.model_path)
+        load_out = load_layer(x, y)
+        self.assertTrue(np.array_equal(out, load_out))
+
+
 if __name__ == '__main__':
     unittest.main()