diff --git a/mercurial/utils/procutil.py b/mercurial/utils/procutil.py
--- a/mercurial/utils/procutil.py
+++ b/mercurial/utils/procutil.py
@@ -642,6 +642,14 @@
     # Raising TypeError here is a little weird. But it is what the standard
     # library does.
     package = pycompat.sysstr(package)
+
+    # Executable relative resources are distributed next to the executable
+    # in special locations, not as proper package resources. We need to handle
+    # them specially.
+    if package == r'mercurial' and executablerelativeresources():
+        p = os.path.dirname(sys.executable)
+        return filesystemresourcereader(pycompat.fsencode(p))
+
     module = importlib.import_module(package)
 
     spec = getattr(module, '__spec__', None)