ENH: raise an error when a Meson installation path looks wrong

Author: dnicolodi

mesonpy/__init__.py

@@ -160,6 +160,8 @@ def _map_to_wheel(sources: Dict[str, Dict[str, Any]]) -> DefaultDict[str, List[T
                 wheel_files[directory].append((path, src))
             else:
                 warnings.warn(f'Installation path {dest!r} for {src!r} could not be mapped to an equivalent wheel directory.')
+                if not re.match(r'^{\w+}$', path.parts[0]):
+                    raise RuntimeError('Meson installation path {dest!r} does not start with a placeholder. Meson bug!')
     return wheel_files