[Bug] send_and_recv and pull may write to wrong places (#2497)

* fix

* fix test

python/dgl/heterograph.py

@@ -4385,9 +4385,9 @@ class DGLHeteroGraph(object):
         u, v = self.find_edges(eid, etype=etype)
         # call message passing onsubgraph
         g = self if etype is None else self[etype]
-        ndata = core.message_passing(_create_compute_graph(g, u, v, eid),
-                                     message_func, reduce_func, apply_node_func)
-        dstnodes = F.unique(v)
+        compute_graph, _, dstnodes, _ = _create_compute_graph(g, u, v, eid)
+        ndata = core.message_passing(
+            compute_graph, message_func, reduce_func, apply_node_func)
         self._set_n_repr(dtid, dstnodes, ndata)
 
     def pull(self,
@@ -4489,9 +4489,10 @@ class DGLHeteroGraph(object):
         g = self if etype is None else self[etype]
         # call message passing on subgraph
         src, dst, eid = g.in_edges(v, form='all')
-        ndata = core.message_passing(_create_compute_graph(g, src, dst, eid, v),
-                                     message_func, reduce_func, apply_node_func)
-        self._set_n_repr(dtid, v, ndata)
+        compute_graph, _, dstnodes, _ = _create_compute_graph(g, src, dst, eid, v)
+        ndata = core.message_passing(
+            compute_graph, message_func, reduce_func, apply_node_func)
+        self._set_n_repr(dtid, dstnodes, ndata)
 
     def push(self,
              u,
@@ -6060,6 +6061,6 @@ def _create_compute_graph(graph, u, v, eid, recv_nodes=None):
 
     return DGLHeteroGraph(hgidx, ([srctype], [dsttype]), [etype],
                           node_frames=[srcframe, dstframe],
-                          edge_frames=[eframe])
+                          edge_frames=[eframe]), unique_src, unique_dst, eid
 
 _init_api("dgl.heterograph")

tests/compute/test_basics.py

@@ -657,3 +657,18 @@ def test_degree_bucket_edge_ordering(idtype):
         assert np.array_equal(eid, np.sort(eid, 1))
         return {'n': F.sum(nodes.mailbox['eid'], 1)}
     g.update_all(fn.copy_e('eid', 'eid'), reducer)
+
+@parametrize_dtype
+def test_issue_2484(idtype):
+    import dgl.function as fn
+    g = dgl.graph(([0, 1, 2], [1, 2, 3]), idtype=idtype, device=F.ctx())
+    x = F.copy_to(F.randn((4,)), F.ctx())
+    g.ndata['x'] = x
+    g.pull([2, 1], fn.u_add_v('x', 'x', 'm'), fn.sum('m', 'x'))
+    y1 = g.ndata['x']
+
+    g.ndata['x'] = x
+    g.pull([1, 2], fn.u_add_v('x', 'x', 'm'), fn.sum('m', 'x'))
+    y2 = g.ndata['x']
+
+    assert F.allclose(y1, y2)