Use 'font-lock-extend-region-functions' in python-mode

* lisp/progmodes/python.el (python-font-lock-extend-region): Change
arguments and return value for 'font-lock-extend-region-functions'.
(python-mode): Change from
'font-lock-extend-after-change-region-function' to
'font-lock-extend-region-functions'.  (Bug#63622)

1 files changed, 19 insertions, 15 deletions

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 032a17c52ff..adaeacc2ec1 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -869,18 +869,22 @@ decorators, exceptions, and assignments.")
 Which one will be chosen depends on the value of
 `font-lock-maximum-decoration'.")
 
-(defun python-font-lock-extend-region (beg end _old-len)
-  "Extend font-lock region given by BEG and END to statement boundaries."
-  (save-excursion
-    (save-match-data
-      (goto-char beg)
-      (python-nav-beginning-of-statement)
-      (setq beg (point))
-      (goto-char end)
-      (python-nav-end-of-statement)
-      (setq end (point))
-      (cons beg end))))
-
+(defvar font-lock-beg)
+(defvar font-lock-end)
+(defun python-font-lock-extend-region ()
+  "Extend font-lock region to statement boundaries."
+  (let ((beg font-lock-beg)
+        (end font-lock-end))
+    (goto-char beg)
+    (python-nav-beginning-of-statement)
+    (beginning-of-line)
+    (when (< (point) beg)
+      (setq font-lock-beg (point)))
+    (goto-char end)
+    (python-nav-end-of-statement)
+    (when (< end (point))
+      (setq font-lock-end (point)))
+    (or (/= beg font-lock-beg) (/= end font-lock-end))))
 
 (defconst python-syntax-propertize-function
   (syntax-propertize-rules
@@ -6704,9 +6708,9 @@ implementations: `python-mode' and `python-ts-mode'."
               `(,python-font-lock-keywords
                 nil nil nil nil
                 (font-lock-syntactic-face-function
-                 . python-font-lock-syntactic-face-function)
-                (font-lock-extend-after-change-region-function
-                 . python-font-lock-extend-region)))
+                 . python-font-lock-syntactic-face-function)))
+  (add-hook 'font-lock-extend-region-functions
+            #'python-font-lock-extend-region nil t)
   (setq-local syntax-propertize-function
               python-syntax-propertize-function)
   (setq-local imenu-create-index-function