_DVCFileSystem returns extra part on relative path. Impact on dvc.api.get_url on r2.34.0

Bug Report

Description

I’ve updated from release 2.8.3 to 2.34.0 and dvc.api.get_url crashes.

Reproduce

Repo structure:

repo_root_dir
  |_ common
      |_ other_deps
          |_ other.bin
  |_ module_a
      |_ dependencies
          |_ dep_1.bin
          |_ dep_2.bin
      |_ my_app.py
      |_ setup.py
  |_ module_b
  |
  .
  .
  . 
  | _module_n

During the building, located at module_a folder, I resolve some binaries dependencies URLs based on path using

dvc.api.get_url('module_a/dependencies/dep_1.bin')

under release 2.8.3 it worked ok but now with release 2.34.0 i got the following error

>>> FileNotFoundError: [Errno 2] No such file or directory: '/Users/myuser/projects/repo_root_dir/module_a/module_a/dependencies/dep_1.bin'

Notice that the module_a part is repeated in the path arisen from the error. Following the code I was able to find that

$ pwd
/Users/myuser/projects/repo_root_dir/module_a/
$ python
>>> from dvc.fs.dvc import _DVCFileSystem

>>> path = module_a/dependencies/dep_1.bin'

>>> dvc_file_system = _DVCFileSystem()
>>> dvc_file_system.path.relparts(path, '/')

Out: 
( 'module_a', 
  'module_a', 
  'dependencies', 
  'dep_1.bin' )

The same but in the repo root directory

$ pwd
/Users/myuser/projects/repo_root_dir/
$ python
>>> from dvc.fs.dvc import _DVCFileSystem

>>> path = module_a/dependencies/dep_1.bin'

>>> dvc_file_system = _DVCFileSystem()
>>> dvc_file_system.path.relparts(path, '/')

Out: 
( 'module_a', 
  'dependencies', 
  'dep_1.bin' )

Lookin the code

Looking at this line https://github.com/iterative/dvc/blob/a6bfc7db4ed3a86c58b4bfac3b22f5ad0b08e338/dvc/fs/dvc.py#L165 Looks like the comparison is not removing the extra part. os.curdir is the local folder . if i tested right.

Hope this helps.

Thanks and grate job!

Environment information

Output of dvc doctor:

$ dvc doctor
DVC version: 2.34.0 (pip)
---------------------------------
Platform: Python 3.8.5 on macOS-11.6.5-x86_64-i386-64bit
Subprojects:
        dvc_data = 0.25.3
        dvc_objects = 0.12.2
        dvc_render = 0.0.12
        dvc_task = 0.1.4
        dvclive = 1.0.1
        scmrepo = 0.1.3
Supports:
        azure (adlfs = 2022.10.0, knack = 0.9.0, azure-identity = 1.7.1),
        http (aiohttp = 3.7.4.post0, aiohttp-retry = 2.8.3),
        https (aiohttp = 3.7.4.post0, aiohttp-retry = 2.8.3)
Cache types: reflink, hardlink, symlink
Cache directory: apfs on /dev/disk1s5s1
Caches: local
Remotes: azure
Workspace directory: apfs on /dev/disk1s5s1
Repo: dvc, git

[giannipablo]

@dberenbaum PR submitted! Please take a look at the fix just to be sure. I tested it and the dvc.api.get_url solved the url properly.

[dberenbaum]

Looks like the comparison is not removing the extra part. os.curdir is the local folder . if i tested right.

By the way, I think this is intentional (sometimes parts[0] == "."), so we should not get rid of this logic, but instead add another check for something like parts[0] == self.path.split(os.getcwd())[-1]. cc @skshetry