get_project 'root' keyword fails silently

[rskye144]

Description

When the get_project function is called with a project root that does not exist, it silently defaults to a project in the current directory.

To reproduce

import signac
project1 = signac.init_project()
project2 = signac.get_project("some/directory/that/does/not/exist")  # this should raise to prevent user error, rather than searching upward from a nonexistent directory
assert project1 == project2  # this is true but we shouldn't get this far

Error also occurs because paths with ~ are not expanded, producing an unexpected error; @bdice suggests could consider adding:

if "~" in root:
    warnings.warn("The character '~' is in the provided root path. Did you mean to call os.path.expanduser(root)?", UserWarning)

Error output

No error is raised (which is wrong, an error/warning should be raised)

[mikemhenry]

@rskye144 👋 thanks for the bug report 😍

Are you interested in contributing a PR to fix this issue? We can provide some help/guidance if you are interested!

[bdice]

I think the right place to put this is below this line:

signac/signac/common/config.py

Line 147 in aed17f3

root = os.getcwd()

I think it should say:

def load_config(root=None, local=False):
    """Load configuration, searching upward from a root path."""
    if root is None:
        root = os.getcwd()
    if not os.path.isdir(root):
        raise ValueError(f"The root directory '{root}' does not exist.")
    # rest of the function

[rskye144]

I can give a PR a try! It will be my first time doing that, so any advice is appreciated.

[bdice]

One key piece that I didn't notice earlier: this bug occurs fails for relative paths contained inside the current directory, when the current directory contains a signac project. Getting a nonexistent absolute path like signac.get_project("/a/fake/path") fails with a LookupError.

[vyasr]

Resolved by #792