Merge pull request #10 from zabertech/10525--ensure-bad-import-yields…

…-useful-error

Fix misleading import error

VERSIONS.md

@@ -81,3 +81,24 @@ Update `pyproject.toml` to be a bit more strict about what python versions are b
 
     Tweaked to fix.
 
+## 3.0.20221124
+
+1. When an `izaber.*` module was being imported, if the module did not exist, the error was vague and non-useful. Amend to
+    to throw a `ModuleNotFoundError` that would allow the developer/user to identify what the issue might be
+
+    ```python
+    (izaber-py3.8) root@7ed4086c1bd9:/src/tests# python 300_import_test.py
+    Traceback (most recent call last):
+      File "300_import_test.py", line 43, in <module>
+        test_submodule()
+      File "300_import_test.py", line 36, in test_submodule
+        import izaber.nonexistant
+      File "<frozen importlib._bootstrap>", line 991, in _find_and_load
+      File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
+      File "<frozen importlib._bootstrap>", line 655, in _load_unlocked
+      File "<frozen importlib._bootstrap>", line 618, in _load_backward_compatible
+      File "/src/izaber/__init__.py", line 28, in load_module
+        if self.spec.name in sys.modules:
+    AttributeError: 'NoneType' object has no attribute 'name'
+    ```
+

izaber/__init__.py

@@ -74,6 +74,8 @@ def attempt_load(self,prefix,module_name):
             for e in target_module.split('.'):
                 package = "_".join(package_path) or None
                 spec = importlib.util.find_spec(e,package)
+                if not spec:
+                    raise ModuleNotFoundError(f"No module named {module_name}")
                 package_path.append(e)
 
             return IZaberLoaderImportlib(spec,module_name)

pyproject.toml

@@ -1,7 +1,7 @@
 [tool.poetry]
 name = "izaber"
 description = "Base load point for iZaber code"
-version = '3.0.20220929'
+version = '3.0.20221124'
 authors = ["Aki Mimoto <aki@zaber.com>"]
 
 [build-system]

tests/300_import_test.py

@@ -31,6 +31,12 @@ def test_submodule():
     # Are objects the same?
     assert id(DATA1) == id(DATA2)
 
+    # Let's import something that doesn't exist
+    try:
+        import izaber.nonexistant
+    except ModuleNotFoundError:
+        pass # this is the error we wish to see
+
 initialize(config='data/izaber.yaml')
 
 test_submodule()