[3.15] gh-153319: Read turtledemo scripts with the source file's own encoding (GH-153321) (#157872)

Co-authored-by: tonghuaroot (童话) <tonghuaroot@gmail.com>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

Author: 4 people

Lib/turtledemo/__main__.py

@@ -333,7 +333,7 @@ def loadfile(self, filename):
         modname = 'turtledemo.' + filename
         __import__(modname)
         self.module = sys.modules[modname]
-        with open(self.module.__file__, 'r') as f:
+        with open(self.module.__file__, encoding='utf-8') as f:
             chars = f.read()
         self.text.delete("1.0", "end")
         self.text.insert("1.0", chars)

Misc/NEWS.d/next/Library/2026-07-08-19-40-00.gh-issue-153319.Qk7bE2.rst

@@ -0,0 +1,2 @@
+The :mod:`turtledemo` viewer now reads each demo script as UTF-8 instead of
+the locale encoding.