From b88130d24b71070df3fb9c5059d236b93c9e68d8 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Sun, 4 Aug 2024 09:35:30 +0000
Subject: [PATCH] The Linux console has some bugs with bright colours. It seems
 likely that it is emulating them by setting a bright (or bold) flag; however,
 when the colour is changed from a bright colour (say SGR 96) to a non-bright
 (say SGR 36), the flag is not reset, so the new colour remains as bright. SGR
 39 (default colour) also does not reset, so you end up with the bright
 default colour. Work around this by sending SGR 0 when switching away from a
 bright colour, and disable AX for TERM=linux. Also make the check for AX
 simpler and do not check for the op capability is not actually used. GitHub
 issue 3976.

---
 options-table.c |  2 +-
 tty.c           | 29 ++++++++++++++---------------
 2 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/options-table.c b/options-table.c
index 20bfb5c7..929ca5e5 100644
--- a/options-table.c
+++ b/options-table.c
@@ -398,7 +398,7 @@ const struct options_table_entry options_table[] = {
 	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SERVER,
 	  .flags = OPTIONS_TABLE_IS_ARRAY,
-	  .default_str = "",
+	  .default_str = "linux*:AX@",
 	  .separator = ",",
 	  .text = "List of terminal capabilities overrides."
 	},
diff --git a/tty.c b/tty.c
index 2064f534..63457fc3 100644
--- a/tty.c
+++ b/tty.c
@@ -2670,28 +2670,18 @@ tty_colours(struct tty *tty, const struct grid_cell *gc)
 	 */
 	if (COLOUR_DEFAULT(gc->fg) || COLOUR_DEFAULT(gc->bg)) {
 		/*
-		 * If don't have AX but do have op, send sgr0 (op can't
-		 * actually be used because it is sometimes the same as sgr0
-		 * and sometimes isn't). This resets both colours to default.
-		 *
+		 * If don't have AX, send sgr0. This resets both colours to default.
 		 * Otherwise, try to set the default colour only as needed.
 		 */
-		have_ax = tty_term_flag(tty->term, TTYC_AX);
-		if (!have_ax && tty_term_has(tty->term, TTYC_OP))
+		if (!tty_term_flag(tty->term, TTYC_AX))
 			tty_reset(tty);
 		else {
 			if (COLOUR_DEFAULT(gc->fg) && !COLOUR_DEFAULT(tc->fg)) {
-				if (have_ax)
-					tty_puts(tty, "\033[39m");
-				else if (tc->fg != 7)
-					tty_putcode_i(tty, TTYC_SETAF, 7);
+				tty_puts(tty, "\033[39m");
 				tc->fg = gc->fg;
 			}
 			if (COLOUR_DEFAULT(gc->bg) && !COLOUR_DEFAULT(tc->bg)) {
-				if (have_ax)
-					tty_puts(tty, "\033[49m");
-				else if (tc->bg != 0)
-					tty_putcode_i(tty, TTYC_SETAB, 0);
+				tty_puts(tty, "\033[49m");
 				tc->bg = gc->bg;
 			}
 		}
@@ -2703,7 +2693,7 @@ tty_colours(struct tty *tty, const struct grid_cell *gc)
 
 	/*
 	 * Set the background colour. This must come after the foreground as
-	 * tty_colour_fg() can call tty_reset().
+	 * tty_colours_fg() can call tty_reset().
 	 */
 	if (!COLOUR_DEFAULT(gc->bg) && gc->bg != tc->bg)
 		tty_colours_bg(tty, gc);
@@ -2851,6 +2841,15 @@ tty_colours_fg(struct tty *tty, const struct grid_cell *gc)
 	struct grid_cell	*tc = &tty->cell;
 	char			 s[32];
 
+	/*
+	 * If the current colour is an aixterm bright colour and the new is not,
+	 * reset because some terminals do not clear bright correctly.
+	 */
+	if (tty->cell.fg >= 90 &&
+	    tty->cell.bg <= 97 &&
+	    (gc->fg < 90 || gc->fg > 97))
+		tty_reset(tty);
+
 	/* Is this a 24-bit or 256-colour colour? */
 	if (gc->fg & COLOUR_FLAG_RGB || gc->fg & COLOUR_FLAG_256) {
 		if (tty_try_colour(tty, gc->fg, "38") == 0)