THRIFT-6391: Import packages that collide with -remote stub locals under an alias

compiler/cpp/src/thrift/generate/t_go_generator.cc

@@ -457,6 +457,19 @@ void t_go_generator::init_generator() {
   package_dir_ = get_out_dir();
   last_const_block_ = 0;
 
+  // The -remote stub's main() declares these local variables. An imported package with one of
+  // these names would be shadowed by them, so reserve them before any import is rendered; such a
+  // package is then imported under an alias in every file of this program.
+  if (!skip_remote_) {
+    for (const char* local :
+         {"cfg",       "client",    "cmd",     "err",      "framed",          "headers",
+          "host",      "httptrans", "iprot",   "m",        "oprot",           "parsedUrl",
+          "parts",     "port",      "portStr", "protocol", "protocolFactory", "trans",
+          "urlString", "useHttp"}) {
+      package_identifiers_set_.insert(local);
+    }
+  }
+
   // This set is taken from https://github.com/golang/lint/blob/master/lint.go#L692
   commonInitialisms.insert("API");
   commonInitialisms.insert("ASCII");

lib/go/test/Makefile.am

@@ -72,7 +72,10 @@ gopath: $(THRIFT) $(THRIFTTEST) \
 				ValidateTest.thrift \
 				ForwardType.thrift \
 				StringParseAllocationTest.thrift \
-				DocCommentTest.thrift
+				DocCommentTest.thrift \
+				RemoteShadowClient.thrift \
+				RemoteShadowHost.thrift \
+				RemoteShadowTest.thrift
 	mkdir -p gopath/src
 	grep -v 'set<Insanity>' $(THRIFTTEST) > ThriftTest.thrift
 	$(THRIFT) $(THRIFTARGS) $(RECURSIVE)
@@ -115,6 +118,7 @@ gopath: $(THRIFT) $(THRIFTTEST) \
 	$(THRIFT) $(THRIFTARGS) ForwardType.thrift
 	$(THRIFT) $(THRIFTARGS) StringParseAllocationTest.thrift
 	$(THRIFT) $(THRIFTARGS) DocCommentTest.thrift
+	$(THRIFT) $(THRIFTARGS) -r RemoteShadowTest.thrift
 	ln -nfs ../../tests gopath/src/tests
 	cp -r ./dontexportrwtest gopath/src
 	touch gopath
@@ -149,7 +153,9 @@ check: gopath
 				./gopath/src/processormiddlewaretest \
 				./gopath/src/clientmiddlewareexceptiontest \
 				./gopath/src/validatetest \
-				./gopath/src/forwardtypetest
+				./gopath/src/forwardtypetest \
+				./gopath/src/remoteshadowtest \
+				./gopath/src/remoteshadowtest/shadow_service-remote
 	$(GO) test github.com/apache/thrift/lib/go/thrift
 	$(GO) test ./gopath/src/tests ./gopath/src/dontexportrwtest
 
@@ -200,6 +206,9 @@ EXTRA_DIST = \
 	OptionalFieldsTest.thrift \
 	ProcessorMiddlewareTest.thrift \
 	RefAnnotationFieldsTest.thrift \
+	RemoteShadowClient.thrift \
+	RemoteShadowHost.thrift \
+	RemoteShadowTest.thrift \
 	RequiredFieldTest.thrift \
 	ServicesTest.thrift \
 	StringParseAllocationTest.thrift \

lib/go/test/RemoteShadowClient.thrift

@@ -0,0 +1,25 @@
+#
+# 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.
+#
+
+// Its Go package is named like a local variable of the generated -remote stub.
+namespace go client
+
+struct Info {
+  1: i32 x
+}

lib/go/test/RemoteShadowHost.thrift

@@ -0,0 +1,25 @@
+#
+# 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.
+#
+
+// Its Go package is named like a local variable of the generated -remote stub.
+namespace go host
+
+struct Addr {
+  1: string name
+}

lib/go/test/RemoteShadowTest.thrift

@@ -0,0 +1,29 @@
+#
+# 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.
+#
+
+// The -remote stub declares local variables such as client and host; packages
+// with those names, used by the arguments below, must not be shadowed by them.
+namespace go remoteshadowtest
+
+include "RemoteShadowClient.thrift"
+include "RemoteShadowHost.thrift"
+
+service ShadowService {
+  void f(1: RemoteShadowClient.Info info, 2: RemoteShadowHost.Addr addr)
+}