`--force` not allowed during `dvc move`

[ntjess]

Bug Report

Description

--force is required to overwrite a file during move, but this isn't allowed as a parameter

Reproduce

1. Create a directory with files a and b, checking both into dvc
2. dvc move a b produces the error
   Use '--force' to overwrite.
3. dvc move --force a b produces the error
   ERROR: unrecognized arguments: --force

Expected

force should allow overwriting

Environment information

Output of dvc doctor:

DVC version: 2.9.3 (pip)
---------------------------------
Platform: Python 3.9.7 on Windows-10-10.0.22000-SP0
Supports:
        gdrive (pydrive2 = 1.10.0),
        webhdfs (fsspec = 2021.11.1),
        http (aiohttp = 3.8.1, aiohttp-retry = 2.4.6),
        https (aiohttp = 3.8.1, aiohttp-retry = 2.4.6)
Cache types: hardlink
Cache directory: NTFS on C:\
Caches: local
Remotes: gdrive
Workspace directory: NTFS on C:\
Repo: dvc, git

[tirkarthi]

Sample test case. The move used to overwrite before 256cb06

def test_move_file_exists(tmp_dir, dvc):
    from dvc.exceptions import OverlappingOutputPathsError

    tmp_dir.dvc_gen({"foo": "foo", "bar": "bar"})
    dvc.move("foo", "bar")

    assert (tmp_dir / "bar").read_text() == "foo"
    assert (tmp_dir / "bar.dvc").exists()
    assert not (tmp_dir / "foo").exists()
    assert not (tmp_dir / "foo.dvc").exists()

commit 256cb06921da79dd5fcb8c35023504a98afdacdf
Author: Peter Rowlands (변기호) <peter@pmrowla.com>
Date:   Wed May 5 13:09:55 2021 +0900

    move: validate new stage before move (#5953)
    
    * move: validate new stage before move
    
    * verify that nothing was moved in tests

[tirkarthi]

A simpler fix would be to pass force=True during new stage creation and I can create a PR. Please let me know if I am missing some other case here.

Edit : force=True probably based on condition like if both source and destination are tracked data sources.

diff --git a/dvc/repo/move.py b/dvc/repo/move.py
index a4f1a7c1..c2dcbf4c 100644
--- a/dvc/repo/move.py
+++ b/dvc/repo/move.py
@@ -67,6 +67,7 @@ def move(self, from_path, to_path):
             wdir=new_wdir,
             outs=[to_path],
             meta=stage.meta,
+            force=True
         )
 
         os.unlink(stage.path)

[pmrowla]

dvc move isn't supposed to have a --force argument, the error message suggesting to use --force is the bug (the message probably comes from stage code that isn't actually applicable during dvc move). The preferred fix here would be to correct the error message.

move overwriting by default prior to that change was a bug and led to unexpected behavior, particularly when dealing with tracked directories (see the original issue that was fixed by that change #5886)

Adding support for --force is something we can consider, but determining when it is allowed is a bit more complicated than just "are both source and data tracked outputs".

[tirkarthi]

Thanks for the clarification @pmrowla . The hint seems to be tightly coupled to the validation function. The hint makes sense for single/pipeline stages created with run as suggested in #4003. Perhaps an additional flag being passed to check_stage_exists like show_hint which is by default is True and dvc.move passes it False through **kwargs while trying to create a stage?

[pmrowla]

I don't think we need an extra flag, the hint in check_stage_exists can probably just be specific to when stage is PipelineStage here:

dvc/dvc/stage/utils.py

Lines 293 to 301 in 92f714e

	hint = "Use '--force' to overwrite."
	if not isinstance(stage, PipelineStage):
	raise StageFileAlreadyExistsError(
	f"'{stage.relpath}' already exists. {hint}"
	)
	elif stage.name and stage.name in dvcfile.stages:
	raise DuplicateStageName(
	f"Stage '{stage.name}' already exists in '{stage.relpath}'. {hint}"
	)

cc: @skshetry