Relative cache-dir breaks the new installer

[matejcik]

• I am on the latest Poetry version.

• I have searched the issues of this repo and believe that this is not a duplicate.

• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Linux Mint 20, Python 3.8.2

• Poetry version: 1.1.0, master

• Link of a Gist with the contents of your pyproject.toml file: https://gist.github.com/matejcik/f7b0d6ca9bea9e6613f7a99433d7ad65

Issue

When cache-dir is set to a relative path (in poetry.toml), bad things happen.

To reproduce:

1. place contents of above gist into a directory
2. poetry install
3. rm -r .venv
4. poetry install again

Expected result: this should work fine

Actual result: a spectacularly unhelpful stack trace with the following error: ValueError: relative path can't be expressed as a file URI

after modifying something or other, the actual stack trace shows up:

ValueError: relative path can't be expressed as a file URI
Traceback (most recent call last):
  File "/home/matejcik/.local/lib/python3.8/site-packages/poetry/installation/executor.py", line 180, in _execute_operation
    result = self._do_execute_operation(operation)
  File "/home/matejcik/.local/lib/python3.8/site-packages/poetry/installation/executor.py", line 255, in _do_execute_operation
    result = getattr(self, "_execute_{}".format(method))(operation)
  File "/home/matejcik/.local/lib/python3.8/site-packages/poetry/installation/executor.py", line 390, in _execute_install
    return self._install(operation)
  File "/home/matejcik/.local/lib/python3.8/site-packages/poetry/installation/executor.py", line 416, in _install
    archive = self._download(operation)
  File "/home/matejcik/.local/lib/python3.8/site-packages/poetry/installation/executor.py", line 559, in _download
    return self._download_link(operation, link)
  File "/home/matejcik/.local/lib/python3.8/site-packages/poetry/installation/executor.py", line 564, in _download_link
    archive = self._chef.get_cached_archive_for_link(link)
  File "/home/matejcik/.local/lib/python3.8/site-packages/poetry/installation/chef.py", line 49, in get_cached_archive_for_link
    archives = self.get_cached_archives_for_link(link)
  File "/home/matejcik/.local/lib/python3.8/site-packages/poetry/installation/chef.py", line 84, in get_cached_archives_for_link
    links.append(Link(archive.as_uri()))

Far as I could tell, archive above is a relative path starting with .cache, which can't be converted to an URI.

After changing the line in chef.py to:

links.append(Link(archive.resolve().as_uri())

the issue goes away. I'm not sure if that is even the right place to fix it, but if yes, I'll send a PR.

[abn]

That should fix the specific issue.

An additional fix may be to resolve the cache-dir value when it is loaded in. However, not sure if there would be any unintentional side-effects in doing so.

[ericriff]

Just came across this myself, on poetry version 1.1.2, but only if I'm using python 3.7. With 3.6 and 3.5 it works as expected.
Also links.append(Link(archive.resolve().as_uri()) worked for me.

[ericriff]

Are you guys going to open a PR for this?
I don't know how the internals of Poetry work, but if it is just that line I don't mind changing it.
I would hate to steal the credit, but it blocking some of my work since I can't move past python 3.6 if I'm using relative paths on the cache.

By the way, I'm using the relative paths as a workaround to in-project only allowing you to have ONE environment per project. I just moved the whole cache inside my project (since we need it to be self contained) and now I can have all the environments I want (I only care about different python versions) inside my project folder.
I'm not sure if there is a better way to do this.

[rvorias]

I accidentally removed the _build/ contents. After restoring them, poetry couldn't be installed due to this error.

Solved it by removing _build/ and .venv/ and ran poetry install which uses the .lock. Seems to be fixed now.

[prusnak]

I was just with the same issue today

[pawamoy]

Same thing in CI when setting cache directory with a relative path: https://github.com/pawamoy/duty/runs/2098788727?check_suite_focus=true

[ericriff]

I would love to have a way to make it relative to pyproject.toml.

[pawamoy]

Here's how I worked around this in CI:

env:
  # To fix an error when running Poetry on Windows
  # (https://github.com/python-poetry/poetry/issues/2629),
  # we set Poetry's cache directory to .poetry_cache in the current directory.
  # It makes it easier to later remove the virtualenv when it's broken.
  # Absolute path is necessary to avoid this issue:
  # https://github.com/python-poetry/poetry/issues/3049
  POETRY_CACHE_DIR: ${{ github.workspace }}/.poetry_cache

Damn it's hard to make things work on Windows.

[finswimmer]

Closing this, because I cannot reproduce this anymore.

Feel free to leave a comment if you disagree.

[github-actions]

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