fixed iterative#3599

1. add new command `dvc remote rename <old> <new>`.
2. add tests for this new command.

dvc/command/remote.py

@@ -108,6 +108,34 @@ def run(self):
         return 0
 
 
+class CmdRemoteRename(CmdRemote):
+    def run(self):
+        conf = self.config.load_one(self.args.level)
+        self._check_exists(conf)
+
+        all_config = self.config.load_config_to_level("all")
+        if self.args.new in all_config.get("remote", {}):
+            raise ConfigError(
+                "Rename failed.Remote name {} already exists.".format(
+                    {self.args.new}
+                )
+            )
+
+        with self.config.edit(self.args.level) as conf:
+            conf["remote"][self.args.new] = conf["remote"][self.args.name]
+            del conf["remote"][self.args.name]
+
+        for level in reversed(self.config.LEVELS):
+            with self.config.edit(level) as conf:
+                if conf["core"].get("remote") == self.args.name:
+                    conf["core"]["remote"] = self.args.new
+
+            if level == self.args.level:
+                break
+
+        return 0
+
+
 def add_parser(subparsers, parent_parser):
     from dvc.command.config import parent_config_parser
 
@@ -224,3 +252,14 @@ def add_parser(subparsers, parent_parser):
         "name", help="Name of the remote to remove."
     )
     remote_remove_parser.set_defaults(func=CmdRemoteRemove)
+    REMOTE_RENAME_HELP = "Rename a data remote"
+    remote_rename_parser = remote_subparsers.add_parser(
+        "rename",
+        parents=[parent_config_parser, parent_parser],
+        description=append_doc_link(REMOTE_RENAME_HELP, "remote/rename"),
+        help=REMOTE_RENAME_HELP,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+    remote_rename_parser.add_argument("name", help="Remote to be renamed")
+    remote_rename_parser.add_argument("new", help="New name of the remote")
+    remote_rename_parser.set_defaults(func=CmdRemoteRename)

tests/func/test_remote.py

@@ -285,3 +285,74 @@ def test_remote_modify_default(dvc):
 
     assert repo_config["core"]["remote"] == remote_repo
     assert local_config["core"]["remote"] == remote_local
+
+
+def test_remote_rename(dvc):
+    remote_name = "drive"
+    remote_url = "gdrive://test/test"
+    new_name = "new"
+    other_name = "other"
+    # prepare
+    assert main(["remote", "add", remote_name, remote_url]) == 0
+    config = dvc.config.load_one("repo")
+    assert config["remote"][remote_name]["url"] == remote_url
+    assert new_name not in config.get("remote", {})
+
+    # rename failed
+    assert main(["remote", "rename", remote_name]) == 254
+    assert main(["remote", "rename", new_name, other_name]) == 251
+    config = dvc.config.load_one("repo")
+    assert config["remote"][remote_name]["url"] == remote_url
+    assert new_name not in config.get("remote", {})
+
+    # rename success
+    assert main(["remote", "rename", remote_name, new_name]) == 0
+    config = dvc.config.load_one("repo")
+    assert remote_name not in config.get("remote", {})
+    assert config["remote"][new_name]["url"] == remote_url
+
+
+def test_remote_duplicated(dvc):
+    remote_name = "drive"
+    remote_url = "gdrive://test/test"
+    used_name = "overlap"
+    another_url = "gdrive://test/test1"
+    # prepare
+    assert main(["remote", "add", remote_name, remote_url]) == 0
+    assert main(["remote", "add", "--local", used_name, another_url]) == 0
+    config = dvc.config.load_one("repo")
+    assert config["remote"][remote_name]["url"] == remote_url
+    local_config = dvc.config.load_one("local")
+    assert local_config["remote"][used_name]["url"] == another_url
+
+    # rename duplicated
+    assert main(["remote", "rename", remote_name, used_name]) == 251
+    config = dvc.config.load_one("repo")
+    assert config["remote"][remote_name]["url"] == remote_url
+    local_config = dvc.config.load_one("local")
+    assert local_config["remote"][used_name]["url"] == another_url
+
+
+def test_remote_default(dvc):
+    remote_name = "drive"
+    remote_url = "gdrive://test/test"
+    new_name = "new"
+    # prepare
+    assert main(["remote", "add", "-d", remote_name, remote_url]) == 0
+    assert main(["remote", "default", "--local", remote_name]) == 0
+    config = dvc.config.load_one("repo")
+    assert config["core"]["remote"] == remote_name
+    assert config["remote"][remote_name]["url"] == remote_url
+    assert new_name not in config.get("remote", {})
+    local_config = dvc.config.load_one("local")
+    assert local_config["core"]["remote"] == remote_name
+
+    # rename success
+    assert main(["remote", "rename", remote_name, new_name]) == 0
+    config = dvc.config.load_one("repo")
+    assert remote_name not in config.get("remote", {})
+    assert config["core"]["remote"] == new_name
+    assert config["remote"][new_name]["url"] == remote_url
+    assert remote_name not in config.get("remote", {})
+    local_config = dvc.config.load_one("local")
+    assert local_config["core"]["remote"] == new_name