how-to

How to Debug a Correctness Mismatch

Step-by-step diagnosis when native output differs from CPython.

Published May 30, 2026

Step 1: Isolate the Input

Find the smallest input that produces different outputs.

Step 2: Compare Outputs

cpython_result = function(data)
native_result = pyvorin.run_native(function, data)
print(cpython_result == native_result)

Step 3: Force Fallback

PYVORIN_FORCE_FALLBACK=1 pyvorin run script.py

Step 4: Report

pyvorin report-failure mismatch_event.json