Avoid assertion violations due to wrong 'min-width' property

* src/xdisp.c (display_min_width): Ignore 'min-width' display
specs which produce stretch glyphs wider than the window when
lines are truncated.  (Bug#73600)

1 files changed, 20 insertions, 9 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 7883c579815..c74e81a3933 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -5689,7 +5689,13 @@ display_min_width (struct it *it, ptrdiff_t charpos,
                                           XCAR (it->min_width_property),
                                           font, true, NULL);
               width -= it->current_x - it->min_width_start;
-              w = list1 (make_int (width));
+              /* It makes no sense to try to obey min-width which yields
+                 a stretch that ends beyond the visible portion of the
+                 window if we are truncating screen lines.  If we are
+                 requested to do that, some Lisp program went awry.  */
+              if (!(it->line_wrap == TRUNCATE
+                    && it->current_x + width > it->last_visible_x))
+                w = list1 (make_int (width));
             }
           else
 #endif
@@ -5699,19 +5705,24 @@ display_min_width (struct it *it, ptrdiff_t charpos,
                                           NULL, true, NULL);
               width -= (it->current_x - it->min_width_start) /
                 FRAME_COLUMN_WIDTH (it->f);
-              w = make_int (width);
+              if (!(it->line_wrap == TRUNCATE
+                    && it->current_x + width > it->last_visible_x))
+                w = make_int (width);
             }
 
           /* Insert the stretch glyph.  */
-          it->object = list3 (Qspace, QCwidth, w);
-          produce_stretch_glyph (it);
-          if (it->area == TEXT_AREA)
+          if (!NILP (w))
             {
-              it->current_x += it->pixel_width;
+              it->object = list3 (Qspace, QCwidth, w);
+              produce_stretch_glyph (it);
+              if (it->area == TEXT_AREA)
+                {
+                  it->current_x += it->pixel_width;
 
-              if (it->continuation_lines_width
-                  && it->string_from_prefix_prop_p)
-                it->wrap_prefix_width = it->current_x;
+                  if (it->continuation_lines_width
+                      && it->string_from_prefix_prop_p)
+                    it->wrap_prefix_width = it->current_x;
+                }
             }
           it->min_width_property = Qnil;
         }