patch 8.1.2153: combining text property and syntax highlight is wrong

Problem:    Combining text property and syntax highlight is wrong. (Nick
            Jensen)
Solution:   Compute the syntax highlight attribute much earlier.
            (closes #5057)

Author: brammool

src/drawline.c

@@ -307,6 +307,7 @@ win_line(
 #endif
 #ifdef FEAT_SPELL
     int		has_spell = FALSE;	// this buffer has spell checking
+    int		can_spell;
 # define SPWORDLEN 150
     char_u	nextline[SPWORDLEN * 2];// text with start of the next line
     int		nextlinecol = 0;	// column where nextline[] starts
@@ -747,6 +748,9 @@ win_line(
 	win_attr = wcr_attr;
 	area_highlighting = TRUE;
     }
+    if (vi_attr != 0 && win_attr != 0)
+	vi_attr = hl_combine_attr(win_attr, vi_attr);
+
 #ifdef FEAT_TEXT_PROP
     if (WIN_IS_POPUP(wp))
 	screen_line_flags |= SLF_POPUP;
@@ -1281,11 +1285,7 @@ win_line(
 	    break;
 	}
 
-	if (draw_state == WL_LINE && (area_highlighting
-#ifdef FEAT_SPELL
-		|| has_spell
-#endif
-	   ))
+	if (draw_state == WL_LINE && (area_highlighting || extra_check))
 	{
 	    // handle Visual or match highlighting in this line
 	    if (vcol == fromcol
@@ -1397,6 +1397,70 @@ win_line(
 	    }
 #endif
 
+	    if (extra_check)
+	    {
+#ifdef FEAT_TERMINAL
+		if (get_term_attr)
+		{
+		    syntax_attr = term_get_attr(wp->w_buffer, lnum, vcol);
+
+		    if (!attr_pri)
+			char_attr = syntax_attr;
+		    else
+			char_attr = hl_combine_attr(syntax_attr, char_attr);
+		}
+#endif
+
+#ifdef FEAT_SYN_HL
+		// Get syntax attribute.
+		if (has_syntax)
+		{
+		    // Get the syntax attribute for the character.  If there
+		    // is an error, disable syntax highlighting.
+		    save_did_emsg = did_emsg;
+		    did_emsg = FALSE;
+
+		    v = (long)(ptr - line);
+		    can_spell = TRUE;
+		    syntax_attr = get_syntax_attr((colnr_T)v,
+# ifdef FEAT_SPELL
+						has_spell ? &can_spell :
+# endif
+						NULL, FALSE);
+
+		    // combine syntax attribute with 'wincolor'
+		    if (syntax_attr != 0 && win_attr != 0)
+			syntax_attr = hl_combine_attr(win_attr, syntax_attr);
+
+		    if (did_emsg)
+		    {
+			wp->w_s->b_syn_error = TRUE;
+			has_syntax = FALSE;
+			syntax_attr = 0;
+		    }
+		    else
+			did_emsg = save_did_emsg;
+# ifdef SYN_TIME_LIMIT
+		    if (wp->w_s->b_syn_slow)
+			has_syntax = FALSE;
+# endif
+
+		    // Need to get the line again, a multi-line regexp may
+		    // have made it invalid.
+		    line = ml_get_buf(wp->w_buffer, lnum, FALSE);
+		    ptr = line + v;
+# ifdef FEAT_CONCEAL
+		    // no concealing past the end of the line, it interferes
+		    // with line highlighting
+		    if (*ptr == NUL)
+			syntax_flags = 0;
+		    else
+			syntax_flags = get_syntax_info(&syntax_seqnr);
+# endif
+		}
+#endif
+	    }
+
 	    // Decide which of the highlight attributes to use.
 	    attr_pri = TRUE;
 #ifdef LINE_ATTR
@@ -1420,7 +1484,12 @@ win_line(
 	    {
 		// Use line_attr when not in the Visual or 'incsearch' area
 		// (area_attr may be 0 when "noinvcur" is set).
-		char_attr = line_attr;
+# ifdef FEAT_SYN_HL
+		if (has_syntax)
+		    char_attr = hl_combine_attr(syntax_attr, line_attr);
+		else
+# endif
+		    char_attr = line_attr;
 		attr_pri = FALSE;
 	    }
 #else
@@ -1741,99 +1810,6 @@ win_line(
 
 	    if (extra_check)
 	    {
-#ifdef FEAT_SPELL
-		int	can_spell = TRUE;
-#endif
-
-#ifdef FEAT_TERMINAL
-		if (get_term_attr)
-		{
-		    syntax_attr = term_get_attr(wp->w_buffer, lnum, vcol);
-
-		    if (!attr_pri)
-			char_attr = syntax_attr;
-		    else
-			char_attr = hl_combine_attr(syntax_attr, char_attr);
-		}
-#endif
-
-#ifdef FEAT_SYN_HL
-		// Get syntax attribute, unless still at the start of the line
-		// (double-wide char that doesn't fit).
-		v = (long)(ptr - line);
-		if (has_syntax && v > 0)
-		{
-		    // Get the syntax attribute for the character.  If there
-		    // is an error, disable syntax highlighting.
-		    save_did_emsg = did_emsg;
-		    did_emsg = FALSE;
-
-		    syntax_attr = get_syntax_attr((colnr_T)v - 1,
-# ifdef FEAT_SPELL
-						has_spell ? &can_spell :
-# endif
-						NULL, FALSE);
-
-		    if (did_emsg)
-		    {
-			wp->w_s->b_syn_error = TRUE;
-			has_syntax = FALSE;
-			syntax_attr = 0;
-		    }
-		    else
-			did_emsg = save_did_emsg;
-
-		    // combine syntax attribute with 'wincolor'
-		    if (win_attr != 0)
-			syntax_attr = hl_combine_attr(win_attr, syntax_attr);
-
-# ifdef SYN_TIME_LIMIT
-		    if (wp->w_s->b_syn_slow)
-			has_syntax = FALSE;
-# endif
-
-		    // Need to get the line again, a multi-line regexp may
-		    // have made it invalid.
-		    line = ml_get_buf(wp->w_buffer, lnum, FALSE);
-		    ptr = line + v;
-
-# ifdef FEAT_TEXT_PROP
-		    // Text properties overrule syntax highlighting or combine.
-		    if (text_prop_attr == 0 || text_prop_combine)
-# endif
-		    {
-			int comb_attr = syntax_attr;
-# ifdef FEAT_TEXT_PROP
-			comb_attr = hl_combine_attr(text_prop_attr, comb_attr);
-# endif
-			if (!attr_pri)
-			{
-#ifdef FEAT_SYN_HL
-			    if (cul_attr)
-				char_attr = hl_combine_attr(
-							  comb_attr, cul_attr);
-			    else
-#endif
-				if (line_attr)
-				char_attr = hl_combine_attr(
-							 comb_attr, line_attr);
-			    else
-				char_attr = comb_attr;
-			}
-			else
-			    char_attr = hl_combine_attr(comb_attr, char_attr);
-		    }
-# ifdef FEAT_CONCEAL
-		    // no concealing past the end of the line, it interferes
-		    // with line highlighting
-		    if (c == NUL)
-			syntax_flags = 0;
-		    else
-			syntax_flags = get_syntax_info(&syntax_seqnr);
-# endif
-		}
-#endif
-
 #ifdef FEAT_SPELL
 		// Check spelling (unless at the end of the line).
 		// Only do this when there is no syntax highlighting, the

src/testdir/dumps/Test_textprop_syn_1.dump

@@ -0,0 +1,6 @@
+>(+0&#40ffff15|a+0#e000e06#ffffff0|b|c|)+0#0000000#40ffff15| +0&#ffffff0@69
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1| 

src/testdir/test_textprop.vim

@@ -652,9 +652,10 @@ endfunc
 
 " screenshot test with textprop highlighting
 func Test_textprop_screenshot_various()
+  CheckScreendump
   " The Vim running in the terminal needs to use utf-8.
-  if !CanRunVimInTerminal() || g:orig_encoding != 'utf-8'
-    throw 'Skipped: cannot make screendumps or not using utf-8'
+  if g:orig_encoding != 'utf-8'
+    throw 'Skipped: not using utf-8'
   endif
   call writefile([
 	\ "call setline(1, ["
@@ -750,9 +751,7 @@ endfunc
 
 " screenshot test with Visual block mode operations
 func Test_textprop_screenshot_visual()
-  if !CanRunVimInTerminal()
-    throw 'Skipped: cannot make screendumps'
-  endif
+  CheckScreendump
 
   " Delete two columns while text props are three chars wide.
   call RunTestVisualBlock(2, '01')
@@ -762,9 +761,7 @@ func Test_textprop_screenshot_visual()
 endfunc
 
 func Test_textprop_after_tab()
-  if !CanRunVimInTerminal()
-    throw 'Skipped: cannot make screendumps'
-  endif
+  CheckScreendump
 
   let lines =<< trim END
        call setline(1, [
@@ -785,6 +782,28 @@ func Test_textprop_after_tab()
   call delete('XtestPropTab')
 endfunc
 
+func Test_textprop_with_syntax()
+  CheckScreendump
+
+  let lines =<< trim END
+       call setline(1, [
+             \ "(abc)",
+             \ ])
+       syn match csParens "[()]" display
+       hi! link csParens MatchParen
+
+       call prop_type_add('TPTitle', #{ highlight: 'Title' })
+       call prop_add(1, 2, #{type: 'TPTitle', end_col: 5})
+  END
+  call writefile(lines, 'XtestPropSyn')
+  let buf = RunVimInTerminal('-S XtestPropSyn', {'rows': 6})
+  call VerifyScreenDump(buf, 'Test_textprop_syn_1', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('XtestPropSyn')
+endfunc
+
 " Adding a text property to a new buffer should not fail
 func Test_textprop_empty_buffer()
   call prop_type_add('comment', {'highlight': 'Search'})

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2153,
 /**/
     2152,
 /**/