Imagine the scenario of shared cache. To set it up, user would do:
```
dvc config cache.dir /path
dvc config cache.shared group
```
Now, when he runs any dvc operation that involves the Repo instance,
RemoteLOCAL will also be initialized and it will currently auto-create
the directory with a regular `os.mkdir`, which is not using group
permissions. To solve that, we can't simply use `self.makdirs` instead,
as it will cause same issues if you run any dvc command before
`dvc config cache.shared group`. So what we should do is create
directories on demand, instead of creating it in advance, same as we do
in other remotes.
The change itself is pretty trivial and involved removing that `mkdir`
line, adjusting tests to not rely on cache dir existence and also
adjusting `dvc version` to not rely on cache directory existance.
Fixes#2563
* test: remove never used copy of load_stage_file()
* dvc: save comments and custom formatting in stage files
* Add a couple of TODOs
* test: test repro doesn't clear comments and formatting in .dvc
As part of this I started writing pytest-like tests and added commonly
used fixtures.
* test: simplify and prettify dvc formatting retained test
Also test that line comments after md5 fields are retained.
* test: fix tests
* dvc: fix stage and metrics opens not closed
* dvc: always use utf-8 in stage files
It used to encode in system default encoding. Not sure if PyYAML was
handling this silently or we were just lucky all the way.
* test: unit test apply_diff()
* test: remove TODOs and ASK
* dvc: polish dvc-formatting PR
* dvc: move stage load/dump utils to a new stage utils file
* dvc: clean up apply_diff()
* test: test stage md5 ignores comments
* test: remove pytests starting marker
Ruslan Kuprieiev
Mr. Outis
Ruslan Kuprieiev
Paweł Redzyński
Jorge Orpinel
Ivan Shcheklein
Andrew Grigorev