Re: Merging the underline attribute at EOL

[Ergus <spacibba@aol.com>]

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Hi Eli:

Please give a look to the attached patch I am still testing it. But just
to check if it solves all the issues you see.  

Best
Ergus

On Tue, Dec 17, 2019 at 05:22:28AM +0200, Eli Zaretskii wrote:
>> Date: Mon, 16 Dec 2019 21:31:56 +0100
>> From: Ergus <spacibba@aol.com>
>> Cc: emacs-devel@gnu.org
>>
>> I had build a wrong branch where I have actually added
>>
>> NILP (face->lface[LFACE_EXTEND_INDEX])
>>
>> to the condition you mention.
>>
>> Actually the question is why there is only:
>>
>> face->box == FACE_NO_BOX
>>
>> Maybe we have to remove it and rely only in the extend attribute?
>
>If the extend attribute is set, but the background color is the same
>as the default, and there's no box/underline/overline/strikethrough
>attributes set, then we can still return early, no?
>

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diff --git a/src/xdisp.c b/src/xdisp.c
index 08c6927052..fdf10894bf 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -21596,13 +21596,17 @@ extend_face_to_end_of_line (struct it *it)
 
   if (FRAME_WINDOW_P (f)
       && MATRIX_ROW_DISPLAYS_TEXT_P (it->glyph_row)
-      && face->box == FACE_NO_BOX
       && FACE_COLOR_TO_PIXEL (face->background, f) == FRAME_BACKGROUND_PIXEL (f)
 #ifdef HAVE_WINDOW_SYSTEM
       && !face->stipple
 #endif
       && !it->glyph_row->reversed_p
-      && !Vdisplay_fill_column_indicator)
+      && !Vdisplay_fill_column_indicator
+      && (NILP (face->lface[LFACE_EXTEND_INDEX])
+          ||(face->box == FACE_NO_BOX
+	     && face->underline == FACE_NO_UNDERLINE
+	     && face->overline_p == false
+	     && face->strike_through_p == false)))
     return;
 
   /* Set the glyph row flag indicating that the face of the last glyph