Fix filling of overlong first lines in Python doc strings

* lisp/progmodes/python.el (python-fill-string): Fill overlong
first lines correctly (bug#20860).

Copyright-paperwork-exempt: yes

1 files changed, 6 insertions, 1 deletions

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 20ec339fffb..f7267bdef29 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -4239,6 +4239,11 @@ JUSTIFY should be used (if applicable) as in `fill-paragraph'."
                     (point)))))
          (num-quotes (python-syntax-count-quotes
                       (char-after str-start-pos) str-start-pos))
+         (str-line-start-pos
+          (save-excursion
+            (goto-char str-start-pos)
+            (beginning-of-line)
+            (point-marker)))
          (str-end-pos
           (save-excursion
             (goto-char (+ str-start-pos num-quotes))
@@ -4262,7 +4267,7 @@ JUSTIFY should be used (if applicable) as in `fill-paragraph'."
             ('symmetric (and multi-line-p (cons 1 1)))))
          (fill-paragraph-function))
     (save-restriction
-      (narrow-to-region str-start-pos str-end-pos)
+      (narrow-to-region str-line-start-pos str-end-pos)
       (fill-paragraph justify))
     (save-excursion
       (when (and (python-info-docstring-p) python-fill-docstring-style)