Are

mypy

types included with

pantsbuild.pants

? In a custom plugin, I'm running into a bunch of these... Maybe it's a Monday morning thing, but I thought I had fixed these before, but can't recall anymore:

pants-plugins/experimental/fooify/rules.py:4: error: Cannot find implementation or library stub for module named "experimental.fooify.subsystem"
pants-plugins/experimental/fooify/rules.py:5: error: Cannot find implementation or library stub for module named "experimental.fooify.target_types"
pants-plugins/experimental/fooify/rules.py:6: error: Cannot find implementation or library stub for module named "pants.core.goals.package"
pants-plugins/experimental/fooify/rules.py:7: error: Cannot find implementation or library stub for module named "pants.engine.fs"
pants-plugins/experimental/fooify/rules.py:8: error: Cannot find implementation or library stub for module named "pants.engine.rules"
pants-plugins/experimental/fooify/rules.py:9: error: Cannot find implementation or library stub for module named "pants.engine.target"
pants-plugins/experimental/fooify/rules.py:15: error: Cannot find implementation or library stub for module named "pants.engine.unions"
pants-plugins/experimental/fooify/rules.py:16: error: Cannot find implementation or library stub for module named "pants.util.logging"

They aren't in a separate

pyi

so yes?

Hmm, I feel like I've misconfigured it, so it's not looking at my requirements correctly. It should pick up the imports. I now vaguely recall I dealt with these at some point while working on the

mypyc

plugin, but my memory is 🥔

You using

pants_requirements

?

Like, when I'm not using Pants? I just mean that

mypy pants-plugins/experimental/fooify/target_types.py

fails, while other 3rd party deps in there succeed...

Is the environment you're running that in have

pants

?

Yep

Can you import the modules it's complaining about?

Yep

config issue perhaps?

I removed all config and everything, added inits everywhere, etc. ANd yeah, pants imports from a terminal python

Unless told otherwise,

mypy

assumes it's in the same environment as your code and dependencies

Yeah, hence my confusion. EVERYTHING other than pants works perfectly

hmm i think we fixed it in like 2.8 or something. why was namespace packages necessary?

I wasn't sure if

pantsbuild.pants

is confusing mypy? Not sure how the internals work

fyi https://github.com/pantsbuild/pants/issues/10944

https://github.com/sureshjoshi/pants-example-plugin/tree/0b8ebcd8618c932b133f00dede71440b16278e53 With this diff:

diff --git a/pants-plugins/experimental/__init__.py b/pants-plugins/experimental/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/pants.toml b/pants.toml
index 3b204b6..4eede6b 100644
--- a/pants.toml
+++ b/pants.toml
@@ -7,12 +7,17 @@ backend_packages = [
     "pants.backend.plugin_development", # Adds the `pants_requirements` target type
     "pants.backend.python",
     "experimental.fooify",
+    "pants.backend.python.typecheck.mypy",
 ]
 
 [source]
 root_patterns = [
     "helloworld",
+    "pants-plugins",
 ]
 
+[python]
+interpreter_constraints = [">=3.9,<3.11"]
+
 [anonymous-telemetry]
 enabled = false

what did you do to resolve this issue? I'm seeing exactly the same thing.

IIRC you can't import modules, you have to import definitions from the modules. Or at least, that bit me

I think I 'solved' it by setting

[tool.mypy]
namespace_packages = true
explicit_package_bases = true

in my pyproject.toml. It was weird. Everything was being type checked correctly. But it still errored about the stubs.

Sorry @ambitious-actor-36781 I didn't see this until now: https://sureshjoshi.com/development/pants-plugin-code-quality#typechecking In my case, I think it was specifically the

namespace_packages

in a

mypy.ini

hm this is really not ideal. anyone mind opening a ticket with a minimal reproduction?