Given the following BUILD file in my repo

./nectl/neuroedge_cli/BUILD

python_sources(name = "neuroedge_cli")

pex_binary(
    name = "nectl",
    dependencies = [":neuroedge_cli"],
    entry_point = "./nectl.py",
)

If I run

./pants run nectl/neuroedge_cli/nectl.py

Everything is fine. If I instead run

./pants run nectl/neuroedge_cli:nectl

It fails with:

12:58:13.40 [ERROR] 1 Exception encountered:

  ProcessExecutionFailure: Process 'Building nectl.neuroedge_cli/nectl.pex with 10 requirements: click==8.1.3, dvg-ringbuffer==1.0.3, keyring==23.5.1, numba==0.56.0, numpy==1.22.4, pandas~=1.4, requests==2.25.1, rich==12.4.1, scipy==1.8.1, tables==3.7.0' failed with exit code 1.
stdout:

stderr:
pid 28706 -> /Users/russellzarse/.cache/pants/named_caches/pex_root/venvs/cac1718c056bb509f51fcdcc0c376b33deaaa8ec/e6831f8bef1e0125d178dbca2c603370d4eeae8a/bin/python -sE /Users/russellzarse/.cache/pants/named_caches/pex_root/venvs/cac1718c056bb509f51fcdcc0c376b33deaaa8ec/e6831f8bef1e0125d178dbca2c603370d4eeae8a/pex --disable-pip-version-check --no-python-version-warning --exists-action a --no-input --isolated -q --cache-dir /Users/russellzarse/.cache/pants/named_caches/pex_root/pip_cache --log /private/var/folders/_d/zt8y2x055597l63bhdztp82c0000gn/T/pants-sandbox-8W6RvT/.tmp/pex-pip-log.ooax9v3d/pip.log download --dest /Users/russellzarse/.cache/pants/named_caches/pex_root/downloads/resolver_download.hetwm61n/usr.local.Cellar.python@3.11.3.11.0.Frameworks.Python.framework.Versions.3.11.bin.python3.11 click==8.1.3 dvg-ringbuffer==1.0.3 keyring==23.5.1 numba==0.56.0 numpy==1.22.4 pandas~=1.4 requests==2.25.1 rich==12.4.1 scipy==1.8.1 tables==3.7.0 --index-url <https://pypi.org/simple/> --retries 5 --timeout 15 exited with 1 and STDERR:
WARNING: Discarding <https://files.pythonhosted.org/packages/b3/23/fd8e7aa70f6c0b41c99de6aae7afc6850ebac2477687e68c6529bfaa41ba/numba-0.56.0.tar.gz#sha256=87a647dd4b8fce389869ff71f117732de9a519fe07663d9a02d75724eb8e244d> (from <https://pypi.org/simple/numba/>) (requires-python:>=3.7). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
ERROR: Could not find a version that satisfies the requirement numba==0.56.0
ERROR: No matching distribution found for numba==0.56.0

If I add

interpreter_constraints

to the

pex_binary

target

pex_binary(
    name = "nectl",
    interpreter_constraints=['CPython==3.8.*'],
    dependencies = [":neuroedge_cli"],
    entry_point = "./nectl.py",
)

run succeed. However...

pex_binary(
    name = "nectl",
    interpreter_constraints=['CPython>=3.8,<4'],
    dependencies = [":neuroedge_cli"],
    entry_point = "./nectl.py",
)

fails in the same way Why does the pex_binary require explicit constraints? Shouldn't the

CPython>=3.8,<4

configuration work?

Hello! What is

[python].interpreter_constraints

set to? Likely the difference is that

run

on a

python_source

target (the file argument) only uses a single interpreter. Whereas

neuroedge_cli:nectl

first builds the PEX you'd get from

./pants package

, then runs it -- those PEXes are built to work with every interpreter constraint you claim it can work with, e.g. 3.8, 3.9, 3.10

At the moment it is the default (not set). I had tried

[python]
interpreter_constraints = ["CPython~=3.8"]

without success

hmm I'm surprised that setting it explicitly didn't fix it. What if you set it explicitly to

Python>=3.8,<4'

like you had in the BUILD file?

It fails with that constraint but the

pants.toml

constraint

[python]
interpreter_constraints = ["CPython==3.8.*"]

succeeds when I remove the explicit constraint on the BUILD target. The tagged version

0.56.0

of

numba

shows min_python_version = "3.7" max_python_version = "3.11" . So it seems that I cannot use >3.8 but I'm not sure why that is only an issue when running via pex rather than targeting source.

ah BUILD file constraints override

[python].interpreter_constraints

, which only sets the defualt

I can't tell, did you all figure out that the `<4`was the killer here? That's a bad default. It includes not just 3.11 but 3.12 alphas out now. We should probably force you to pick ICs and not default for you.

@enough-analyst-54434 does that mean the error I'm encountering will be fixed in an upcoming pants release? I was able to narrow this down to interpretter 3.11. I think that is what John said

the PEX runtime will figure out 3.11 is no good and use 3.10

So I now have, in my

pants.toml

[python]
interpreter_constraints = ["CPython==3.10.*"]

and that works. Plus, its a reasonable project-wide constraint (I believe) ...oh man, I just found a note on the numba install page

Numba is compatible with Python 3.7–3.10

That explains why the library was not compatible though I'm still learning how to interpret that

WARNING: Discarding <https://files.pythonhosted>

error message. Interestingly, I was not encountering this issue before I added Python 3.10.9 to my pyenv related to another project. Not sure if there is any causation or if I created the issue while configuring other dependencies. Thanks very much for helping me understand and resolve this. I believe I am in good shape.

@aloof-appointment-30987 no, that Pex issue was fixed quite some time ago and Pants has the fix. It was not the issue here at all. The issue here was purely using inappropriate (no) ICs. Now that you're using appropriate ICs, you should be good.