Fix fill-paragraph in python docstrings (Bug#36056)

* lisp/progmodes/python.el (python-do-auto-fill): New function.
(python-mode): Set it as normal-auto-fill-function, and don't set
fill-indent-according-to-mode.  Having the latter set during
fill-paragraph gives wrongs result, because python-indent-line doesn't
remove indentation added by filling.
* test/lisp/progmodes/python-tests.el (python-fill-docstring): New
test.

1 files changed, 7 insertions, 1 deletions

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 14b65669c4b..ec5d8c55512 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -4084,6 +4084,12 @@ JUSTIFY should be used (if applicable) as in `fill-paragraph'."
       (goto-char (line-end-position))))
   t)
 
+(defun python-do-auto-fill ()
+  "Like `do-auto-fill', but bind `fill-indent-according-to-mode'."
+  ;; See Bug#36056.
+  (let ((fill-indent-according-to-mode t))
+    (do-auto-fill)))
+
 
 ;;; Skeletons
 
@@ -5379,7 +5385,7 @@ REPORT-FN is Flymake's callback function."
   (set (make-local-variable 'paragraph-start) "\\s-*$")
   (set (make-local-variable 'fill-paragraph-function)
        #'python-fill-paragraph)
-  (set (make-local-variable 'fill-indent-according-to-mode) t) ; Bug#36056.
+  (set (make-local-variable 'normal-auto-fill-function) #'python-do-auto-fill)
 
   (set (make-local-variable 'beginning-of-defun-function)
        #'python-nav-beginning-of-defun)