BUG: Need graceful error message when passing a path object as `depends_on`

[hmgaudecker]

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pytask.

• (optional) I have confirmed this bug exists on the main branch of pytask.

---

To reproduce

Pass a pathlib.Path object as dependency to some task which points to a file that does not exist.

Problem description

The error message is cryptic even to the semi-initiated and it does not provide information on which file

Traceback (most recent call last):
  File "/home/xxx/miniconda3/envs/epp/lib/python3.8/site-packages/_pytask/resolve_dependencies.py", line 144, in _check_if_root_nodes_are_available
    dag.nodes[node]["node"].state()
  File "/home/xxx/miniconda3/envs/epp/lib/python3.8/site-packages/_pytask/nodes.py", line 180, in state
    raise NodeNotFoundError
_pytask.exceptions.NodeNotFoundError

During handling of the above exception, another exception occurred:

ValueError: A node must be defined in a child of 'paths'.

Expected Output

At a very minimum, line 180 of nodes.py should become

raise NodeNotFoundError(self.value)

but a more graceful error message pointing the user at what is causing this might be useful!

[tobiasraabe]

I cannot reproduce it with 0.0.13 and 0.0.11. I imagine your setup is like this:

import pytask
from pathlib import Path


@pytask.mark.depends_on(Path("some_text.txt"))
def task_hm():
    pass

Then, executing pytask yields

(pytask) C:\Users\tobia\git\pytask [main ≡ +3 ~0 -0 !]> pytask .\example\ -k task_hm
======================================= Start pytask session ========================================
Platform: win32 -- Python 3.7.10, pytask 0.0.13, pluggy 0.13.1
Root: C:/Users/tobia/git/pytask/example
Collected 1 task. Deselected 8 tasks.
============================== Failures during resolving dependencies ===============================

_pytask.exceptions.ResolvingDependenciesError: There are some dependencies missing which do not exist and are not produced by any task. See the following dictionary with missing nodes as keys and dependent tasks as values.

{'example/some_text.txt': ['example/task_example.py::task_hm']}

=====================================================================================================

BTW, in the upcoming release it will be the following. Please, leave a comment if you like it or have another suggestion.

(pytask) C:\Users\tobia\git\pytask [rich ≡ +3 ~0 -0 !]> pytask .\example\ -k task_hm
──────────────────────────────────────── Start pytask session ────────────────────────────────────────
Platform: win32 -- Python 3.7.10, pytask 0.0.13+22.g0263743, pluggy 0.13.1
Root: C:\Users\tobia\git\pytask\example
Collected 1 task. Deselected 8 tasks.

─────────────────────────────── Failures during resolving dependencies ───────────────────────────────

ResolvingDependenciesError: Some dependencies do not exist or are not produced by any task. See the
following tree which shows which dependencies are missing for which tasks.

Missing dependencies:
└── 📄 example/some_text.txt
    └── 📝 example/task_example.py::task_hm

──────────────────────────────────────────────────────────────────────────────────────────────────────

[hmgaudecker]

New layout looks great!!!

Hmmm, I was also on 0.13, didn't have time to dive too deeply into it.

Anyhow, if that line above is still there, I'd think that it would be weakly improving things if you added the name of the node to the error message. I ended up there, after all and more information is always better.