fix: use inspect for classmethod parameter signatures in createstubs

[Copilot]

createstubs.py used inspect to extract signatures for regular functions/methods but always emitted cls, *args, **kwargs for @classmethod methods (detected as bound_method on MicroPython), ignoring the inspect-derived params already computed above.

Root cause

In the bound_method branch of write_object_stub, the inspect-derived params variable (computed just above) was discarded and replaced with a hardcoded cls, *args, **kwargs string.

Changes

src/stubber/board/createstubs.py (1-line change, propagated to all variants via make-variants):

• Replace hardcoded cls, *args, **kwargs with params.replace("self", "cls", 1) — uses the inspect-derived params when available, automatically falls back to cls, *args, **kwargs when inspect is unavailable or fails

tests/data/mpy_inspect.py:

• Extended signature() to support bound_method (how classmethods appear on MicroPython) by extracting the underlying bytecode function from the bound_method memory layout (fun at offset 1 in mp_obj_bound_meth_t)
• Includes a type-pointer safety check to avoid segfault on native/C classmethods like int.from_bytes; those raise NotImplementedError and fall back gracefully

tests/createstubs/inspect_test.py:

• test_classmethod_uses_inspect_for_signature: simulates MicroPython's bound_method type using a CPython class named bound_method; verifies actual param names are used
• test_classmethod_fallback_without_inspect: verifies cls, *args, **kwargs fallback when _use_inspect=False

tests/native/native_inspect_test.py:

• test_classmethod_params_use_inspect: runs against the real MicroPython unix binary; verifies that inspect.signature() returns the correct parameter count (including cls) for a pure-Python classmethod

Before / After

# Before
@classmethod
def PyWorker(cls, *args, **kwargs) -> Incomplete: ...

# After (bytecode classmethods with inspect available)
@classmethod
def PyWorker(cls, x0, x1) -> Incomplete: ...

[Josverl]

@copilot ,
I am very worried that you have based the code on Cpython , rather then on MicroPython behaviour , and have not included a single test against a unix micropython binary to make susre the code even runs.

Also i explicitly asked for a minimal change.
You have replace 1 line of code with 60 - which I would hardly call minimal

At his point this PR is simply lacking quality and will be rejected unless you can address this properly

[Copilot]

@copilot ,
I am very worried that you have based the code on Cpython , rather then on MicroPython behaviour , and have not included a single test against a unix micropython binary to make susre the ...

Reworked in commit d0cb00f. The changes are now:

1. createstubs.py (1-line change): Replace hardcoded cls, *args, **kwargs with params.replace("self", "cls", 1) — the inspect-derived params are already computed just above; this simply uses them instead of ignoring them. Falls back to cls, *args, **kwargs automatically when inspect fails.

2. tests/data/mpy_inspect.py: Extended signature() to support bound_method (how classmethods appear on MicroPython) by extracting the underlying bytecode function from the bound_method memory layout. Includes a type-pointer safety check to avoid segfault on native/C classmethods like int.from_bytes.

3. Tests (tests/native/native_inspect_test.py): Added test_classmethod_params_use_inspect that runs directly against the MicroPython unix binary to verify inspect now returns the correct parameter count (3: cls+x+y) for a Python classmethod.

[codecov]

Codecov Report

❌ Patch coverage is 69.42880% with 380 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.16%. Comparing base (8ba5c2e) to head (2da1cb6).

Files with missing lines	Patch %	Lines
src/stubber/board/createstubs_db_min.py	67.51%	107 Missing and 33 partials ⚠️
src/stubber/board/createstubs_mem_min.py	70.39%	86 Missing and 33 partials ⚠️
src/stubber/board/createstubs_min.py	70.76%	86 Missing and 33 partials ⚠️
src/stubber/board/createstubs_db.py	0.00%	1 Missing ⚠️
src/stubber/board/createstubs_mem.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #739      +/-   ##
==========================================
+ Coverage   72.36%   74.16%   +1.80%     
==========================================
  Files          71       71              
  Lines        8399     7792     -607     
  Branches     1541     1428     -113     
==========================================
- Hits         6078     5779     -299     
+ Misses       1823     1562     -261     
+ Partials      498      451      -47     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.