fix: use importlib to load bindings module explicitly

The wheel structure has both isomdl_uniffi.py (module) and isomdl_uniffi/ (package
 containing the .so file). Python prefers packages over modules, so the standard
import statement would find the empty package __init__.py instead of the bindings.

This fix uses importlib.util to explicitly load the .py file by path.

Signed-off-by: Adam Burdett <burdettadam@gmail.com>

Author: burdettadam

python/isomdl_uniffi/__init__.py

@@ -14,25 +14,37 @@
 
 __version__ = "0.1.0"
 
-# Import the main module - try multiple paths to handle different wheel structures
+import importlib.util
+import os
+import sys
+
 _imported = False
 _import_error = None
 
-# Try: isomdl_uniffi/isomdl_uniffi.py (generated by maturin for mixed projects)
-if not _imported:
-    try:
-        from .isomdl_uniffi import *
-        _imported = True
-    except ImportError as e:
-        _import_error = e
+# The wheel structure has both:
+# - isomdl_uniffi/isomdl_uniffi.py (the Python bindings)
+# - isomdl_uniffi/isomdl_uniffi/ (directory containing the .so)
+# Python prefers packages over modules, so we must explicitly load the .py file.
 
-# Try: isomdl_uniffi/isomdl_uniffi/isomdl_uniffi.py (nested structure)
-if not _imported:
+_module_dir = os.path.dirname(os.path.abspath(__file__))
+_bindings_path = os.path.join(_module_dir, "isomdl_uniffi.py")
+
+if os.path.exists(_bindings_path):
     try:
-        from .isomdl_uniffi.isomdl_uniffi import *
-        _imported = True
-    except ImportError:
-        pass
+        spec = importlib.util.spec_from_file_location(
+            "_isomdl_uniffi_bindings", _bindings_path
+        )
+        if spec and spec.loader:
+            _bindings_module = importlib.util.module_from_spec(spec)
+            sys.modules["_isomdl_uniffi_bindings"] = _bindings_module
+            spec.loader.exec_module(_bindings_module)
+            # Export everything from the bindings module
+            _all_exports = getattr(_bindings_module, "__all__", [])
+            for _name in _all_exports:
+                globals()[_name] = getattr(_bindings_module, _name)
+            _imported = True
+    except Exception as e:
+        _import_error = e
 
 if not _imported:
     raise ImportError(
@@ -41,3 +53,4 @@
         f"Please run './python/precommit/build-bindings.sh' first. "
         f"Original error: {_import_error}"
     )
+