Fix namespace detection crash (#2949)

Signed-off-by: Emmanuel Ferdman <emmanuelferdman@gmail.com>

Author: emmanuel-ferdman

ChangeLog

@@ -71,6 +71,10 @@ Release date: TBA
 
   Closes #2923
 
+* Fix ``is_namespace()`` crash when search locations contain ``pathlib.Path`` objects.
+
+  Closes #2942
+
 What's New in astroid 4.0.3?
 ============================
 Release date: 2026-01-03

astroid/interpreter/_import/util.py

@@ -95,7 +95,10 @@ def is_namespace(modname: str) -> bool:
             # But immediately return False if we can detect we are in stdlib
             # or external lib (e.g site-packages)
             if any(
-                any(location.startswith(lib_dir) for lib_dir in STD_AND_EXT_LIB_DIRS)
+                any(
+                    str(location).startswith(lib_dir)
+                    for lib_dir in STD_AND_EXT_LIB_DIRS
+                )
                 for location in found_spec.submodule_search_locations
             ):
                 return False