opentelemetry-python: PyLance / mypy doesn't accept `opentelemetry` as a namespace package

I opened this PR to see if we can add the necessary docs for mypy use: https://github.com/open-telemetry/opentelemetry.io/pull/1611

@sk- Thanks I figured out the same but forgot to post here. I find it a bit surprising that mypy requires you to set flags depending on details of your dependencies but that seems more like a mypy issue than a opentelemetry one.

As in it’s way more obvious that I have to set the namespace flag if I am typechecking a package that is it self a namespace package than when typechecking a package that happens to depend on a namespace package

@jenshnielsen for mypy you need to set namespace_packages = True or the command line option --namespace-packages. See https://github.com/open-telemetry/opentelemetry-python/issues/1608#issuecomment-1075799695

I also had to add:

[mypy-opentelemetry.sdk.*]
implicit_reexport = True

It’s a pity this info is not readily available in docs.

I ran into an issue typechecking import from opentelemetry-sdk

Running

mypy .\test.py

where test.py simply contains an import from opentelemetry-sdk

from opentelemetry.sdk.trace import TracerProvider

results in

test.py:1:1: error: Cannot find implementation or library stub for module named "opentelemetry.sdk.trace"
test.py:1:1: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
Found 1 error in 1 file (checked 1 source file)

Adding a __init__.pyi note the i to the toplevelfolder of opentelemetry here https://github.com/open-telemetry/opentelemetry-python/tree/main/opentelemetry-api/src/opentelemetry whould resolve the issue and the code type checks correctly.

Are there strong arguments against adding such a file ? I understand thata adding a __init__.py file is not a good idea but addign a __init__.pyi file seems fine? I note that opentelemetry-sdk it self ships such a file here which seems to have been created when that package it self was converted to a namespace package.

Seen with

python 3.8 and the following versions

opentelemetry-api                     1.12.0rc2
opentelemetry-instrumentation         0.32b0
opentelemetry-instrumentation-logging 0.32b0
opentelemetry-sdk                     1.12.0rc2
opentelemetry-semantic-conventions    0.32b0
mypy                                  0.971
mypy-extensions                       0.4.3

This was fixed in https://github.com/microsoft/pylance-release/issues/2562 — and there’s an action point for this project to be more PEP-compatible:

The opentelemetry library is placing the “py.typed” file in the top-level namespace directory rather than within the individual submodules. Pyright is currently looking for it in the submodule directories, consistent with PEP 561.

Then it should all work