diff --git a/mercurial/utils/resourceutil.py b/mercurial/utils/resourceutil.py
--- a/mercurial/utils/resourceutil.py
+++ b/mercurial/utils/resourceutil.py
@@ -8,7 +8,6 @@
 # GNU General Public License version 2 or any later version.
 
 
-import _imp
 import os
 import sys
 
@@ -24,7 +23,12 @@ def mainfrozen():
     return (
         hasattr(sys, "frozen")  # new py2exe
         or hasattr(sys, "importers")  # old py2exe
-        or _imp.is_frozen("__main__")  # tools/freeze
+        or getattr(
+            getattr(sys.modules.get('__main__'), '__spec__', None),
+            'origin',
+            None,
+        )
+        == 'frozen'  # tools/freeze
     )
 
 
@@ -44,7 +48,6 @@ if mainfrozen() and getattr(sys, "frozen
         assert dirs[0] == b"mercurial"
         return os.path.join(_rootpath, *dirs[1:])
 
-
 else:
     datapath = os.path.dirname(os.path.dirname(pycompat.fsencode(__file__)))
     _rootpath = os.path.dirname(datapath)
@@ -90,7 +93,6 @@ except (ImportError, AttributeError):
         for p in os.listdir(path):
             yield pycompat.fsencode(p)
 
-
 else:
     from .. import encoding