Eagerly warn/error when a project is under a path with `:` (because unix will cry when you put it on PATH)

[lemorage]

I used uv venv --python 3.10 to create a virtual env and activated it. Under this venv, I created a main.py containing a single line of code print('Hello world!'). However, when I ran the script using uv run, I got the error saying path segment contains separator ':'.

(me) ☁  me [master] ⚡  uv run main.py --verbose
error: path segment contains separator `:`
(me) ☁  me [master] ⚡  python main.py
Hello world!

• macos version: Sequoia 15.1
• The current uv version: uv 0.5.1 (Homebrew 2024-11-08)

[charliermarsh]

I've never seen this before -- I assume it has to do with something unusual in some path on your machine. What does pwd look like? What about your $PATH?

[lemorage]

ohh, thank u so much for your suggestions! I checked my CWD, and it turns out the issue was indeed caused by an unusual character in the directory name. The : in the path below was causing the problem:

/Users/clannad/Dev/mercurius/ucb/cs194:294-196_fa24/me/

[charliermarsh]

No prob, thanks for following up!

[mtnmbr]

Hey, I am currently trying to move my CI setup from poetry to uv with docker on jenkins and am experiencing a similar error when trying to sync my venv.

Locally everything is fine, but on CI when running uv sync --locked --verbose am getting the following error:

error: Failed to prepare distributions
  Caused by: Failed to build `component-config-util @ file:///srv/dsadock/atvmces/workspace/r_feature_replace-poetry-with-uv/component_config_util`
  Caused by: Failed to build PATH for build script
  Caused by: path segment contains separator `:`
script returned exit code 2

uv version is 0.4.23

EDIT:

resolved. this has been a setting related to the resoultion of my UV_CACHE environment variable. It introduced windows like paths into the cache folder and this produced the above error.

The respective error line was just slightly above:

DEBUG Released lock at `/srv/dsadock/atvmces/workspace/r_feature_replace-poetry-with-uv/d:\slave\workspace\r_feature_replace-poetry-with-uv/.cache/uv/sdists-v4/editable/c5ec13b93a5ad88a/.lock`

sorry for the noise

[knl]

I'm encountering a similar problem, but I don't think : is an unusual character for UNIX paths. Is this limitation because of Windows?

[Gankra]

This appears to be a fundamental limitation with unix and key environment variables. i.e. PATH is a :-delimited value, so if you need to add anything to PATH that contains a : you just... Can't. There's apparently no escaping, you just lose.

This is relevant if e.g. we want to create a venv under such a path and run your project in it.

We can potentially add a better eager diagnostic for this, as cargo did in rust-lang/cargo#11318