Fix a missing newline when using the pipe command between the scrollback and screen contents

See #1642

docs/changelog.rst

@@ -10,6 +10,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Add support for the underscore key found in some keyboard layouts
   (:iss:`1639`)
 
+- Fix a missing newline when using the pipe command between the
+  scrollback and screen contents (:iss:`1642`)
+
 
 0.14.0 [2019-05-24]
 ---------------------

kitty/screen.c

@@ -2310,6 +2310,7 @@ static PyMemberDef members[] = {
     {"grman", T_OBJECT_EX, offsetof(Screen, grman), READONLY, "grman"},
     {"color_profile", T_OBJECT_EX, offsetof(Screen, color_profile), READONLY, "color_profile"},
     {"linebuf", T_OBJECT_EX, offsetof(Screen, linebuf), READONLY, "linebuf"},
+    {"main_linebuf", T_OBJECT_EX, offsetof(Screen, main_linebuf), READONLY, "main_linebuf"},
     {"historybuf", T_OBJECT_EX, offsetof(Screen, historybuf), READONLY, "historybuf"},
     {"scrolled_by", T_UINT, offsetof(Screen, scrolled_by), READONLY, "scrolled_by"},
     {"lines", T_UINT, offsetof(Screen, lines), READONLY, "lines"},

kitty/window.py

@@ -487,6 +487,8 @@ class Window:
                 sanitizer = text_sanitizer(as_ansi, add_wrap_markers)
                 h = list(map(sanitizer, h))
             self.screen.historybuf.as_text(h.append, as_ansi, add_wrap_markers)
+            if not self.screen.linebuf.is_continued(0) and h:
+                h[-1] += '\n'
             lines = chain(h, lines)
         return ''.join(lines)