[cherry-pick] fix bug of varbase.__getitem__, test=develop (#24647)

* fix bug of varbase.__getitem__, test=develop (#24642)

* fix bug of varbase.__getitem__, test=develop

* fix bug of float and other type, test=develop

* fix unittest, test=develop

Author: zhiqiu

paddle/fluid/pybind/imperative.cc

@@ -221,6 +221,71 @@ static imperative::NameVarBaseMap ConvertToNameVarBaseMap(
   return result;
 }
 
+static bool PyCheckInteger(PyObject *obj) {
+#if PY_VERSION_HEX < 0x03000000
+  return (PyLong_Check(obj) || PyInt_Check(obj)) && !PyBool_Check(obj);
+#else
+  return PyLong_Check(obj) && !PyBool_Check(obj);
+#endif
+}
+
+// NOTE(zhiqiu): Revised version of PySlice_GetIndices. From:
+// https://github.com/python/cpython/blob/8d21aa21f2cbc6d50aab3f420bb23be1d081dac4/Objects/sliceobject.c#L103
+// Original PySlice_GetIndices return wrong result when
+// slice_item contains long int, such as arr[:180L].
+// NOT sure why this happens !!!
+// Besides, PySlice_GetIndices cannot raise error when float in slice item.
+// So, I make a revised version of PySlice_GetIndices, named to
+// _PySlice_GetIndices. Try to use _PySlice_Unpack which is more robust than
+// PySlice_GetIndices in the future.
+static int _PySlice_GetIndices(PySliceObject *r, Py_ssize_t length,
+                               Py_ssize_t *start, Py_ssize_t *stop,
+                               Py_ssize_t *step) {
+  /* XXX support long ints */
+  if (r->step == Py_None) {
+    *step = 1;
+  } else {
+    if (PyCheckInteger(r->step)) {
+      *step = PyLong_AsLong(r->step);
+    } else {
+      PADDLE_THROW(platform::errors::InvalidArgument(
+          "Currently, VarBase.__getitem__() only allows None or integers in "
+          "slice item, but received %s.",
+          std::string(Py_TYPE(r->step)->tp_name)));
+    }
+  }
+  if (r->start == Py_None) {
+    *start = *step < 0 ? length - 1 : 0;
+  } else {
+    if (PyCheckInteger(r->start)) {
+      *start = PyLong_AsLong(r->start);
+    } else {
+      PADDLE_THROW(platform::errors::InvalidArgument(
+          "Currently, VarBase.__getitem__() only allows None or integers in "
+          "slice item, but received %s.",
+          std::string(Py_TYPE(r->start)->tp_name)));
+    }
+    if (*start < 0) *start += length;
+  }
+  if (r->stop == Py_None) {
+    *stop = *step < 0 ? -1 : length;
+  } else {
+    if (PyCheckInteger(r->stop)) {
+      *stop = PyLong_AsLong(r->stop);
+    } else {
+      PADDLE_THROW(platform::errors::InvalidArgument(
+          "Currently, VarBase.__getitem__() only allows None or integers in "
+          "slice item, but received %s.",
+          std::string(Py_TYPE(r->stop)->tp_name)));
+    }
+    if (*stop < 0) *stop += length;
+  }
+  if (*stop > length) return -1;
+  if (*start >= length) return -1;
+  if (*step == 0) return -1;
+  return 0;
+}
+
 static void ParseIndexingSlice(framework::LoDTensor *tensor, PyObject *_index,
                                std::vector<int> *slice_axes,
                                std::vector<int> *slice_starts,
@@ -245,16 +310,17 @@ static void ParseIndexingSlice(framework::LoDTensor *tensor, PyObject *_index,
           "too many indices (%d) for tensor of dimension %d", size, rank));
   for (int dim = 0; dim < size; ++dim) {
     PyObject *slice_item = PyTuple_GetItem(index, dim);
-    PADDLE_ENFORCE_EQ(
-        PyNumber_Check(slice_item) || PySlice_Check(slice_item), true,
-        platform::errors::InvalidArgument(
-            "We allow indexing by Integers, Slices, and tuples of "
-            "these types, but received %s in %dth slice item",
-            std::string(Py_TYPE(slice_item)->tp_name), dim + 1));
+    PADDLE_ENFORCE_EQ(PyCheckInteger(slice_item) || PySlice_Check(slice_item),
+                      true,
+                      platform::errors::InvalidArgument(
+                          "Currently, VarBase.__getitem__() only allows "
+                          "indexing by Integers, Slices, and tuples of "
+                          "these types, but received %s in %dth slice item",
+                          std::string(Py_TYPE(slice_item)->tp_name), dim + 1));
     infer_flags->push_back(1);
     int dim_len = shape[dim];
-    if (PyNumber_Check(slice_item)) {
-      // integer
+    if (PyCheckInteger(slice_item)) {
+      // integer, PyLong_AsLong supports both int and long
       int start = static_cast<int>(PyLong_AsLong(slice_item));
       start = start < 0 ? start + dim_len : start;
       slice_axes->push_back(dim);
@@ -263,17 +329,15 @@ static void ParseIndexingSlice(framework::LoDTensor *tensor, PyObject *_index,
       slice_strides->push_back(1);
       decrease_axis->push_back(dim);
     } else {
-      // slice
+      // slice item
       Py_ssize_t start, end, step;
-// The parameter type for the slice parameter was PySliceObject* before 3.2
-#if PY_VERSION_HEX >= 0x03020000
-      PySlice_GetIndices(slice_item, dim_len, &start, &end, &step);
-#else
-      PySlice_GetIndices(reinterpret_cast<PySliceObject *>(slice_item), dim_len,
-                         &start, &end, &step);
-#endif
+      PySliceObject *p = reinterpret_cast<PySliceObject *>(slice_item);
+      _PySlice_GetIndices(p, dim_len, &start, &end, &step);
+
       // :: or : or 0:dim_len:1
-      if (start == 0 && end == dim_len && step == 1) continue;
+      if (start == 0 && end == dim_len && step == 1) {
+        continue;
+      }
       slice_axes->push_back(dim);
       slice_starts->push_back(start);
       slice_ends->push_back(end);
@@ -481,7 +545,6 @@ void BindImperative(py::module *m_ptr) {
              ParseIndexingSlice(tensor, _index.ptr(), &slice_axes,
                                 &slice_starts, &slice_ends, &slice_strides,
                                 &decrease_axis, &infer_flags);
-
              // release gil and do tracing
              py::gil_scoped_release release;
              const auto &tracer = imperative::GetCurrentTracer();
@@ -621,8 +684,8 @@ void BindImperative(py::module *m_ptr) {
            [](imperative::VarBase &self,
               const imperative::detail::BackwardStrategy &bckst,
               const imperative::Tracer &tracer) {
-             // TODO(jiabin): when we impl more backward execution we can select
-             // them
+             // TODO(jiabin): when we impl more backward execution we can
+             // select them
              auto *engine = tracer.GetEngine();
              engine->Init(&self, bckst);
              VLOG(3) << "Start backward";

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

@@ -0,0 +1,50 @@
+#   Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+import numpy as np
+import paddle.fluid as fluid
+
+
+class TestImperativeVarBaseGetItem(unittest.TestCase):
+    def test_getitem_with_long(self):
+        with fluid.dygraph.guard():
+            data = np.random.random((2, 80, 16128)).astype('float32')
+            var = fluid.dygraph.to_variable(data)
+            sliced = var[:, 10:, :var.shape[1]]  # var.shape[1] is 80L here
+            self.assertEqual(sliced.shape, [2, 70, 80])
+
+            sliced = var[:, var.shape[0]:, var.shape[0]:var.shape[1]]
+            self.assertEqual(sliced.shape, [2, 78, 78])
+
+    def test_getitem_with_float(self):
+        def test_float_in_slice_item():
+            with fluid.dygraph.guard():
+                data = np.random.random((2, 80, 16128)).astype('float32')
+                var = fluid.dygraph.to_variable(data)
+                sliced = var[:, 1.1:, :var.shape[1]]
+
+        self.assertRaises(Exception, test_float_in_slice_item)
+
+        def test_float_in_index():
+            with fluid.dygraph.guard():
+                data = np.random.random((2, 80, 16128)).astype('float32')
+                var = fluid.dygraph.to_variable(data)
+                sliced = var[1.1]
+
+        self.assertRaises(Exception, test_float_in_index)
+
+
+if __name__ == '__main__':
+    unittest.main()