[misc] Fix build warnings (#6037)

Co-authored-by: Hongzhi (Steve), Chen <chenhongzhi.nkcs@gmail.com>

python/dgl/heterograph_index.py

@@ -1017,7 +1017,7 @@ class HeteroGraphIndex(ObjectBase):
             raise DGLError("Invalid incidence matrix type: %s" % str(typestr))
         return inc, shuffle_idx
 
-    def node_subgraph(self, induced_nodes, relabel_nodes):
+    def node_subgraph(self, induced_nodes):
         """Return the induced node subgraph.
 
         Parameters
@@ -1025,9 +1025,6 @@ class HeteroGraphIndex(ObjectBase):
         induced_nodes : list of utils.Index
             Induced nodes. The length should be equal to the number of
             node types in this heterograph.
-        relabel_nodes : bool
-            If True, the extracted subgraph will only have the nodes in the specified node set
-            and it will relabel the nodes in order.
 
         Returns
         -------
@@ -1035,7 +1032,7 @@ class HeteroGraphIndex(ObjectBase):
             The subgraph index.
         """
         vids = [F.to_dgl_nd(nodes) for nodes in induced_nodes]
-        return _CAPI_DGLHeteroVertexSubgraph(self, vids, relabel_nodes)
+        return _CAPI_DGLHeteroVertexSubgraph(self, vids)
 
     def edge_subgraph(self, induced_edges, preserve_nodes):
         """Return the induced edge subgraph.

python/dgl/subgraph.py

@@ -161,7 +161,7 @@ def node_subgraph(
         nodes.get(ntype, F.copy_to(F.tensor([], graph.idtype), device))
         for ntype in graph.ntypes
     ]
-    sgi = graph._graph.node_subgraph(induced_nodes, relabel_nodes)
+    sgi = graph._graph.node_subgraph(induced_nodes)
     induced_edges = sgi.induced_edges
     if not relabel_nodes:
         sgi = graph._graph.edge_subgraph(induced_edges, True)

src/array/libra_partition.cc

@@ -383,9 +383,9 @@ List<Value> Libra2dglBuildDict(
   while (!feof(fp) && edge < fsize) {
     int64_t u, v;
     float w;
-    fscanf(
-        fp, "%ld,%ld,%f\n", &u, &v,
-        &w);  // reading an edge - the src and dst global node IDs
+    CHECK_EQ(
+        fscanf(fp, "%ld,%ld,%f\n", &u, &v, &w),
+        3);  // reading an edge - the src and dst global node IDs
 
     if (indices_ptr[u] ==
         -100) {  // if already not assigned a local node ID, local node ID is

src/graph/heterograph_capi.cc

@@ -403,7 +403,6 @@ DGL_REGISTER_GLOBAL("heterograph_index._CAPI_DGLHeteroVertexSubgraph")
     .set_body([](DGLArgs args, DGLRetValue* rv) {
       HeteroGraphRef hg = args[0];
       List<Value> vids = args[1];
-      bool relabel_nodes = args[2];
       std::vector<IdArray> vid_vec;
       vid_vec.reserve(vids.size());
       for (Value val : vids) {

src/graph/sampler.cc

@@ -1169,11 +1169,15 @@ NegSubgraph EdgeSamplerObject::genNegEdgeSubgraph(
       }
       prev_neg_offset = neg_vids.size();
       randomSample(num_tot_nodes, neg_sample_size, exclude, &neg_vids);
-      assert(prev_neg_offset + neg_sample_size == neg_vids.size());
+      assert(
+          static_cast<size_t>(prev_neg_offset + neg_sample_size) ==
+          neg_vids.size());
     } else if (neg_sample_size < num_tot_nodes) {
       prev_neg_offset = neg_vids.size();
       randomSample(num_tot_nodes, neg_sample_size, &neg_vids);
-      assert(prev_neg_offset + neg_sample_size == neg_vids.size());
+      assert(
+          static_cast<size_t>(prev_neg_offset + neg_sample_size) ==
+          neg_vids.size());
     } else if (exclude_positive) {
       LOG(FATAL) << "We can't exclude positive edges"
                     "when sampling negative edges with all nodes.";