[build] Catch exception thrown by non-pip ROOT install

Author: jase231

bindings/pyroot/pythonizations/python/ROOT/__init__.py

@@ -19,6 +19,7 @@
 from importlib.abc import Loader, MetaPathFinder
 from importlib.machinery import ModuleSpec
 from importlib.metadata import version
+from importlib.metadata import PackageNotFoundError
 
 from . import _asan  # noqa: F401  # imported for side effects for setup specific to AddressSanitizer environments
 from ._facade import ROOTFacade
@@ -192,17 +193,19 @@ def find_spec(self, fullname: str, path, target=None) -> ModuleSpec:
         # from . import JsMVA
 
 # Print a warning for users of the ROOT wheel alpha distribution
-if "a" in version("ROOT"):
-    import warnings
-
-    warnings.warn(
-        "This distribution of ROOT is in alpha stage. Feedback is welcome and appreciated. "
-        "Feel free to reach out to the user forum for questions and general feedback at "
-        "https://github.com/root-project/root/issues. "
-        "Do not rely on this distribution for production purposes.",
-        stacklevel=2,  # emit the warning in the caller
-    )
-
+try:
+    if "a" in version("ROOT"):
+        import warnings
+
+        warnings.warn(
+            "This distribution of ROOT is in alpha stage. Feedback is welcome and appreciated. "
+            "Feel free to reach out to the user forum for questions and general feedback at "
+            "https://github.com/root-project/root/issues. "
+            "Do not rely on this distribution for production purposes.",
+            stacklevel=2,  # emit the warning in the caller
+        )
+except:
+    pass
 
 def _cleanup():
     # Delete TBrowser instances while the GUI event loop is still alive,