pull: Unclear error message when remote support is not installed

Bug Report

Description

If you’ve installed DVC via pip without the remote support you need (for example S3), the error message is very unclear.

Reproduce

1. Setup fresh repo & pip install dvc[s3]
2. Copy dataset.zip to repo
3. dvc init & dvc add dataset.zip
4. Setup remote & dvc push
5. Move to fresh python environment
6. pip install dvc
7. Clone repo
8. dvc pull -v

Expected

I would’ve expected an error message saying something like: “the remote type (s3) is not supported in your dvc installation”.

Instead you get the following output:

$ dvc pull -v
2021-10-26 10:35:07,698 DEBUG: failed to pull cache for 'models'      
2021-10-26 10:35:07,699 DEBUG: failed to pull cache for 'data/evaluation'
2021-10-26 10:35:08,269 WARNING: No file hash info found for 'data/evaluation'. It won't be created.                                                                                                                                            
2021-10-26 10:35:08,304 WARNING: No file hash info found for 'models'. It won't be created.                                                                                                                                                     
2 files failed                                                                                                                                                                                                                                  
2021-10-26 10:35:08,326 ERROR: failed to pull data from the cloud - Checkout failed for following targets:
data/evaluation
models
Is your cache up to date?
<https://error.dvc.org/missing-files>

Took me a couple hours to figure it out I had to reinstall dvc with s3 support enabled 😅

Environment information

Output of dvc doctor:

$ dvc doctor

DVC version: 2.8.2 (pip)
---------------------------------
Platform: Python 3.9.7 on Linux-4.14.246-187.474.amzn2.x86_64-x86_64-with-glibc2.31
Supports:
        webhdfs (fsspec = 2021.10.1),
        http (aiohttp = 3.7.4.post0, aiohttp-retry = 2.4.5),
        https (aiohttp = 3.7.4.post0, aiohttp-retry = 2.4.5),
Cache types: hardlink, symlink
Cache directory: nfs4 on xxxxxx.efs.eu-west-1.amazonaws.com:/data-pvc
Caches: local
Remotes: s3
Workspace directory: nfs4 on xxxxx.efs.eu-west-1.amazonaws.com:/data-pvc
Repo: dvc, git

[efiop]

Hm, the everything is up to date is definitely a bug though. And I can indeed reproduce that warning as well, looking into it…

EDIT: when odb (aka cache dir) is not accessible, we fail to load the corresponding object and thus checkout throws those warnings that are clearly no longer relevant.

[nsorros]

@nsorros Please post full verbose log for dvc pull -v and post dvc doctor output.

The error I was getting will be addressed by #7501