Merge pull request #1895 from lschmelting/dev

Support debug=True if native namespace-packages are present

Author: alexcjohnson

CHANGELOG.md

@@ -195,6 +195,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - [#1778](https://github.com/plotly/dash/pull/1778) DataTable: Fix React warnings stating
   that each child in a list should have a unique "key" prop
 
+- [#1895](https://github.com/plotly/dash/pull/1895) Support debug=True if native namespace-packages are present
+
 ## [2.0.0] - 2021-08-03
 
 ## Dash and Dash Renderer

dash/dash.py

@@ -1731,12 +1731,18 @@ def enable_dev_tools(
                 if isinstance(package, ModuleSpec)
                 else os.path.dirname(package.path)
                 if hasattr(package, "path")
+                else os.path.dirname(
+                    package._path[0]  # pylint: disable=protected-access
+                )
+                if hasattr(package, "_path")
                 else package.filename
                 for package in packages
             ]
 
             for i, package in enumerate(packages):
-                if "dash/dash" in os.path.dirname(package.path):
+                if hasattr(package, "path") and "dash/dash" in os.path.dirname(
+                    package.path
+                ):
                     component_packages_dist[i : i + 1] = [
                         os.path.join(os.path.dirname(package.path), x)
                         for x in ["dcc", "html", "dash_table"]