fix: handle missing resource config in node version helpers

apisix/resource.lua

@@ -94,13 +94,21 @@ end
 
 function _M.get_nodes_ver(resource_path)
     local res_conf = fetch_latest_conf(resource_path)
+    if not res_conf then
+        return nil
+    end
+
     local upstream = res_conf.value.upstream or res_conf.value
     return upstream._nodes_ver
 end
 
 
 function _M.set_nodes_ver_and_nodes(resource_path, nodes_ver, nodes)
     local res_conf = fetch_latest_conf(resource_path)
+    if not res_conf then
+        return
+    end
+
     local upstream = res_conf.value.upstream or res_conf.value
     upstream._nodes_ver = nodes_ver
     upstream.nodes = nodes

t/core/resource.t

@@ -0,0 +1,61 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You 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.
+#
+use t::APISIX 'no_plan';
+
+run_tests;
+
+__DATA__
+
+=== TEST 1: get_nodes_ver returns nil when the resource does not exist
+--- config
+    location /t {
+        content_by_lua_block {
+            local resource = require("apisix.resource")
+            ngx.say(resource.get_nodes_ver("/apisix/upstreams/missing-resource"))
+        }
+    }
+--- request
+GET /t
+--- response_body
+nil
+--- error_log
+resource not found: missing-resource in /upstreams
+--- no_error_log
+[error]
+[alert]
+
+
+
+=== TEST 2: set_nodes_ver_and_nodes does not fail when the resource does not exist
+--- config
+    location /t {
+        content_by_lua_block {
+            local resource = require("apisix.resource")
+            resource.set_nodes_ver_and_nodes("/apisix/upstreams/missing-resource", 1,
+                                             {["127.0.0.1:1980"] = 1})
+            ngx.say("passed")
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+--- error_log
+resource not found: missing-resource in /upstreams
+--- no_error_log
+[error]
+[alert]