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, 24 insertions, 0 deletions

diff --git a/test/lisp/progmodes/python-tests.el b/test/lisp/progmodes/python-tests.el
index 3e653cb568a..1af579bb7a4 100644
--- a/test/lisp/progmodes/python-tests.el
+++ b/test/lisp/progmodes/python-tests.el
@@ -5432,6 +5432,30 @@ buffer with overlapping strings."
     (run-python nil nil 'show)
     (should (eq buffer (current-buffer)))))
 
+(ert-deftest python-tests--fill-long-first-line ()
+  (should
+   (equal
+    (with-temp-buffer
+      (insert "def asdf():
+    \"\"\"123 123 123 123 123 123 123 123 123 123 123 123 123 SHOULDBEWRAPPED 123 123 123 123
+
+    \"\"\"
+    a = 1
+")
+      (python-mode)
+      (goto-char (point-min))
+      (forward-line 1)
+      (end-of-line)
+      (fill-paragraph)
+      (buffer-substring-no-properties (point-min) (point-max)))
+    "def asdf():
+    \"\"\"123 123 123 123 123 123 123 123 123 123 123 123 123
+    SHOULDBEWRAPPED 123 123 123 123
+
+    \"\"\"
+    a = 1
+")))
+
 (provide 'python-tests)
 
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