Relative import error when running model-checker on submodule examples.py files

[benbrastmckie]

Bug Description

When running model-checker examples.py from within a subdirectory (e.g., counterfactual/), the tool fails with a relative import error.

Steps to Reproduce

1. Run model-checker to create a new project (this works correctly)
2. Navigate to a subtheory directory: cd subtheories/counterfactual/
3. Run: model-checker examples.py

Expected Behavior

The model-checker should be able to load and run the examples.py file from the subdirectory.

Actual Behavior

The following error occurs:

Traceback (most recent call last):
  File "/Users/nicky/Library/Python/3.13/lib/python/site-packages/model_checker/builder/strategies.py", line 179, in import_module
    spec.loader.exec_module(module)
  File "<frozen importlib._bootstrap_external>", line 1026, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/Users/nicky/Documents/project_ten/subtheories/counterfactual/examples.py", line 34, in <module>
    from ...operators import LogosOperatorRegistry
ImportError: attempted relative import with no known parent package

During handling of the above exception, another exception occurred:

model_checker.builder.errors.PackageImportError: Failed to import module 'examples'
Context: Path: examples.py, Error: attempted relative import with no known parent package
Suggestion: Check module syntax and dependencies.

Root Cause Analysis

The issue appears to be that when model-checker directly loads a Python file, it doesn't establish the proper package context for relative imports to work. The file subtheories/counterfactual/examples.py contains:

from ...operators import LogosOperatorRegistry
from ...semantic import LogosSemantics, LogosProposition, LogosModelStructure

These relative imports expect the file to be loaded as part of a package structure, but when model-checker loads it directly, Python doesn't know what the parent packages are.

Potential Solutions

1. Modify model-checker's import strategy: When loading a module, detect if it's part of a package structure and set up the proper package context.

2. Support absolute imports: Allow the examples.py files to use absolute imports when run directly (perhaps with a fallback mechanism).

3. Add a package discovery mechanism: Automatically detect and set up the package hierarchy based on the presence of __init__.py files.

Environment

• Python: 3.13
• model-checker version: (latest from pip)
• OS: macOS Darwin 24.6.0

Workaround

Currently, users may need to run the examples from the project root directory or modify the import statements to be absolute imports when running files directly.