Fixed error when filename too long

src/_pytest/config/__init__.py

@@ -528,9 +528,14 @@ class PytestPluginManager(PluginManager):
             if i != -1:
                 path = path[:i]
             anchor = absolutepath(current / path)
+            try:
                 if anchor.exists():  # we found some file object
                     self._try_load_conftest(anchor, namespace.importmode, rootpath)
                     foundanchor = True
+            except OSError:
+                import pytest
+
+                raise pytest.UsageError(f"file or directory not found: {anchor}")
         if not foundanchor:
             self._try_load_conftest(current, namespace.importmode, rootpath)