Backport of r59654.

Issue #4342: Always convert Text.index result to string.

Lib/lib-tk/Tkinter.py

@@ -3005,7 +3005,7 @@ class Text(Widget):
         return self.tk.call(self._w, "image", "names")
     def index(self, index):
         """Return the index in the form line.char for INDEX."""
-        return self.tk.call(self._w, 'index', index)
+        return str(self.tk.call(self._w, 'index', index))
     def insert(self, index, chars, *args):
         """Insert CHARS before the characters at INDEX. An additional
         tag can be given in ARGS. Additional CHARS and tags can follow in ARGS."""

Misc/NEWS

@@ -109,6 +109,8 @@ Core and builtins
 Library
 -------
 
+- Issue #4342: Always convert Text.index result to string.
+
 - Issue 3248: Allow placing ScrolledText in a PanedWindow.
 
 - Issue #4084: Fix max, min, max_mag and min_mag Decimal methods to