#19591 Opaque 'failed to read link' error when running with a non-ignored venv Issue created by huonw Describe the bug When running pants with a non-ignored Python venv in the source tree, commands like

pants tailor ::

or

pants test ::

explode with an opaque error:

IntrinsicError: Failed to read link "/Users/huon/tmp/pants-venv/venv/bin/python": Absolute symlink: "/Users/huon/.pyenv/versions/3.9.10/bin/python"

This is particularly confusing for onboarding: many people using Python will be used to creating venvs by default, and they may not have it ignored, especially while just experimenting with Pants for the first time. The error message could be improved. On two levels: 1. generically, for any absolute symlink: the error message could be more specific about these symlinks being a problem, why, and how to fix (e.g. remove, or ignore) 2. for this common venv case, Pants could have heuristics to detect venv-like paths (e.g. containing a folder name like

venv

or

.venv

, or a link like

.../bin/python

) and suggest things like removing the venv (not necessary with pants) and/or ignoring it Some workarounds 1. remove the venv(s) entirely 2. add the venv(s) to

.gitignore

(adjacent to

pants.toml

) 3. add the venv(s) to

pants_ignore

in

pants.toml

, e.g.

[GLOBAL]
    ...
    pants_ignore.add = ["venv"]

Reproducer:

cd $(mktemp -d)

cat > pants.toml <<EOF
[GLOBAL]
pants_version = "2.16.0"
backend_packages = ["pants.backend.python"]

[anonymous-telemetry]
enabled = false
EOF

python -m venv venv

pants tailor ::

Output:

15:09:44.41 [INFO] Initializing scheduler...
15:09:48.47 [INFO] Scheduler initialized.
15:09:48.49 [ERROR] 1 Exception encountered:

Engine traceback:
  in `tailor` goal

IntrinsicError: Failed to read link "/private/var/folders/sv/vd266m4d4lvctgs2wpnhjs9w0000gn/T/tmp.Lw7I6aDt/venv/bin/python": Absolute symlink: "/Users/huon/.pyenv/versions/3.9.10/bin/python"

Pants version 2.16.0 OS macOS Additional info https://pantsbuild.slack.com/archives/C046T6T9U/p1691744178310219 pantsbuild/pants