Fix the CSI J (Erase in display ED) escape code not removing line continued markers

Fixes #2809

Remains to write tests for this.

docs/changelog.rst

@@ -23,6 +23,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 
 - Wayland: Fix a crash when using animated mouse cursors (:iss:`2810`)
 
+- Fix the CSI J (Erase in display ED) escape code not removing line continued
+  markers (:iss:`2809`)
+
 
 0.18.1 [2020-06-23]
 --------------------

kitty/line-buf.c

@@ -51,6 +51,12 @@ linebuf_mark_line_clean(LineBuf *self, index_type y) {
     self->line_attrs[y] &= ~TEXT_DIRTY_MASK;
 }
 
+void
+linebuf_mark_line_as_not_continued(LineBuf *self, index_type y) {
+    self->line_attrs[y] &= ~CONTINUED_MASK;
+}
+
+
 static PyObject*
 clear(LineBuf *self, PyObject *a UNUSED) {
 #define clear_doc "Clear all lines in this LineBuf"

kitty/lineops.h

@@ -96,6 +96,7 @@ void linebuf_set_attribute(LineBuf *, unsigned int , unsigned int );
 void linebuf_rewrap(LineBuf *self, LineBuf *other, index_type *, index_type *, HistoryBuf *, index_type *, index_type *);
 void linebuf_mark_line_dirty(LineBuf *self, index_type y);
 void linebuf_mark_line_clean(LineBuf *self, index_type y);
+void linebuf_mark_line_as_not_continued(LineBuf *self, index_type y);
 unsigned int linebuf_char_width_at(LineBuf *self, index_type x, index_type y);
 void linebuf_refresh_sprite_positions(LineBuf *self);
 void historybuf_add_line(HistoryBuf *self, const Line *line);

kitty/screen.c

@@ -1188,6 +1188,7 @@ screen_erase_in_display(Screen *self, unsigned int how, bool private) {
                 line_apply_cursor(self->linebuf->line, self->cursor, 0, self->columns, true);
             }
             linebuf_mark_line_dirty(self->linebuf, i);
+            linebuf_mark_line_as_not_continued(self->linebuf, i);
         }
         self->is_dirty = true;
         self->selection = EMPTY_SELECTION;