Fix vertical layout calculations when newline has line-height property

* src/xdisp.c (move_it_in_display_line_to): Reset the iterator's
'constrain_row_ascent_descent_p' flag after processing the
newline, similar to what 'display_line' does.  Without this, the
flag remains set once set by x_produce_glyphs, and causes the
vertical layout calculations to go awry, because Emacs thinks the
screen lines have zero height.	(Bug#23850)

1 files changed, 5 insertions, 0 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index bcb283f8faa..da0e84f0043 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -9038,6 +9038,11 @@ move_it_in_display_line_to (struct it *it,
             }
           else
             result = MOVE_NEWLINE_OR_CR;
+          /* If we've processed the newline, make sure this flag is
+             reset, as it must only be set when the newline itself is
+             processed.  */
+          if (result == MOVE_NEWLINE_OR_CR)
+            it->constrain_row_ascent_descent_p = false;
           break;
         }