Environment variable substitution in cmd scripts

[dbohdan]

Is your feature/enhancement proposal related to a problem? Please describe.

When I tried migrating a project's tasks from Poe the Poet, an independent task runner for Poetry, I ran into a feature that is important to me missing.

Poe can substitute environment variables in cmd tasks, which are like PDM cmd scripts. Here is an example of how I use it:

[tool.poe.env]
"PYTHON_SOURCES" = "src tests"

[tool.poe.tasks.format]
cmd = "ruff format ${PYTHON_SOURCES}"
help = "Run the Ruff formatter"

[tool.poe.tasks.lint]
cmd = "ruff check ${PYTHON_SOURCES}"
help = "Run Ruff"

I find this useful because it allows you to avoid repeating yourself without invoking an external shell. Why shell scripts aren't a sufficient alternative: the shell depends on the platform. On Windows this is still cmd.exe, which has an incompatible syntax for variable substitution.

Describe the solution you'd like

I would like to be able to substitute environment variables as {env:PYTHON_SOURCES} or something similar consistent with existing PDM syntax ({args} and {pdm}) in cmd scripts.

[frostming]

Currently "ruff check ${PYTHON_SOURCES}" also works in PDM cmd, doesn't it work for you?

[dbohdan]

No. Here is a demo of what doesn't work for me.

> cat pyproject.toml
[project]
name = "pdm-test"
version = "0.1.0"
description = "Default template for PDM package"
authors = [
    {name = "D. Bohdan", email = "[email protected]"},
]
dependencies = []
requires-python = "==3.11.*"
readme = "README.md"
license = {text = "MIT"}


[tool.pdm]
package-type = "application"

[tool.pdm.scripts]
_.env = { PYTHON_SOURCES = "test.py" }

foo.shell = "python ${PYTHON_SOURCES}"
bar.cmd = "python ${PYTHON_SOURCES}"

> cat test.py
print("Hello")

> pdm run foo
Hello

> pdm run bar
/home/dbohdan/.local/share/pdm/venvs/pdm-test-q1q4PxnD-3.11/bin/python: can't open file '/tmp/pdm-test/${PYTHON_SOURCES}': [Errno 2] No such file or directory

> pdm --version
PDM, version 2.11.2

[frostming]

No. Here is a demo of what doesn't work for me.

Okay, the problem is _.env isn't loaded into the current process, but only takes effect in the subprocess

[dbohdan]

The scripts also succeed/fail the same way with

[tool.pdm.scripts]
foo.shell = "python ${PYTHON_SOURCES}"
foo.env = { PYTHON_SOURCES = "test.py" }

bar.cmd = "python ${PYTHON_SOURCES}"
bar.env = { PYTHON_SOURCES = "test.py" }

[frostming]

if you set env before executing you will find it runs successful