Fix hangs caused by unbalanced braces in Python f-strings

* lisp/progmodes/python.el (python--font-lock-f-strings):
Temporarily bind forward-sexp-function to nil when calling
'up-list'.  (Bug#74738)

1 files changed, 2 insertions, 1 deletions

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 5729b12573f..493eab5e611 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -623,7 +623,8 @@ the {...} holes that appear within f-strings."
               (forward-char 1)          ;Just skip over {{
             (let ((beg (match-beginning 0))
                   (end (condition-case nil
-                           (let ((parse-sexp-ignore-comments))
+                           (let ((forward-sexp-function)
+                                 (parse-sexp-ignore-comments))
                              (up-list 1)
                              (min send (point)))
                          (scan-error send))))