cli: fix overwriting remotes in dvc remote add

dvc/command/remote.py

@@ -5,12 +5,17 @@
 import re
 
 import dvc.logger as logger
-from dvc.command.base import fix_subparsers, append_doc_link
-from dvc.config import Config
+from dvc.command.base import append_doc_link, fix_subparsers
 from dvc.command.config import CmdConfig
+from dvc.config import Config
+from dvc.exceptions import ConfirmRemoveError, DvcException
 
 
 class CmdRemoteAdd(CmdConfig):
+    def _prevent_config_overwriting(self, section):
+        if (section in self.configobj.keys()) and not self.args.force:
+            raise ConfirmRemoveError(section)
+
     @staticmethod
     def resolve_path(path, config_file):
         """Resolve path relative to config file location.
@@ -39,6 +44,13 @@ def run(self):
             )
 
         section = Config.SECTION_REMOTE_FMT.format(self.args.name)
+
+        try:
+            self._prevent_config_overwriting(section)
+        except DvcException as exc:
+            logger.error(exc)
+            return 1
+
         ret = self._set(section, Config.SECTION_REMOTE_URL, self.args.url)
         if ret != 0:
             return ret
@@ -156,6 +168,13 @@ def add_parser(subparsers, parent_parser):
         default=False,
         help="Set as default remote.",
     )
+    remote_add_parser.add_argument(
+        "-f",
+        "--force",
+        action="store_true",
+        default=False,
+        help="Force overwriting existing configs",
+    )
     remote_add_parser.set_defaults(func=CmdRemoteAdd)
 
     REMOTE_DEFAULT_HELP = "Set/unset default remote."

dvc/exceptions.py

@@ -179,8 +179,8 @@ def __init__(self, stages):
 class ConfirmRemoveError(DvcException):
     def __init__(self, path):
         super(ConfirmRemoveError, self).__init__(
-            "unable to remove '{}' without a confirmation from the user. Use "
-            "'-f' to force.".format(path)
+            "unable to remove or overwrite '{}' without a confirmation "
+            "from the user. Use '-f' to force.".format(path)
         )
 
 

tests/test_remote.py

@@ -57,6 +57,15 @@ def test_relative_path(self):
         config = configobj.ConfigObj(self.dvc.config.config_file)
         self.assertEqual(config['remote "mylocal"']["url"], rel)
 
+    def test_overwrite(self):
+        remote_name = "a"
+        remote_url = "s3://bucket/name"
+        main(["remote", "add", remote_name, remote_url])
+        self.assertEqual(main(["remote", "add", remote_name, remote_url]), 1)
+        self.assertEqual(
+            main(["remote", "add", "-f", remote_name, remote_url]), 0
+        )
+
 
 class TestRemoteRemoveDefault(TestDvc):
     def test(self):