If default-terminal is set to "screen" or "screen-*", emulate screen's

historical (incorrect) behaviour for SGR 3 and send smso
(standout). Previously, we would send sitm (italics) if the terminal
outside had it and smso otherwise. This was acceptably until recently
because xterm's terminfo entry lacked sitm, so most users got smso.

People who want italics should set default-terminal to the forthcoming
"tmux" entry (and be prepared to deal with it being missing on older
hosts).

As a side-effect this changes default-terminal to be a server rather
than a session option.

suggested by and ok naddy

4 files changed, 37 insertions, 24 deletions

diff --git a/options-table.c b/options-table.c
index 5e21c692..089a9b86 100644
--- a/options-table.c
+++ b/options-table.c
@@ -61,6 +61,11 @@ const struct options_table_entry server_options_table[] = {
 	  .default_num = 20
 	},
 
+	{ .name = "default-terminal",
+	  .type = OPTIONS_TABLE_STRING,
+	  .default_str = "screen"
+	},
+
 	{ .name = "escape-time",
 	  .type = OPTIONS_TABLE_NUMBER,
 	  .minimum = 0,
@@ -143,11 +148,6 @@ const struct options_table_entry session_options_table[] = {
 	  .default_str = _PATH_BSHELL
 	},
 
-	{ .name = "default-terminal",
-	  .type = OPTIONS_TABLE_STRING,
-	  .default_str = "screen"
-	},
-
 	{ .name = "destroy-unattached",
 	  .type = OPTIONS_TABLE_FLAG,
 	  .default_num = 0
diff --git a/server-fn.c b/server-fn.c
index 85067a87..0e6e4d46 100644
--- a/server-fn.c
+++ b/server-fn.c
@@ -36,7 +36,7 @@ server_fill_environ(struct session *s, struct environ *env)
 	long	pid;
 
 	if (s != NULL) {
-		term = options_get_string(&s->options, "default-terminal");
+		term = options_get_string(&global_options, "default-terminal");
 		environ_set(env, "TERM", term);
 
 		idx = s->id;
diff --git a/tmux.1 b/tmux.1
index 5bf77829..a7f5f3ef 100644
--- a/tmux.1
+++ b/tmux.1
@@ -2266,6 +2266,19 @@ Available server options are:
 Set the number of buffers; as new buffers are added to the top of the stack,
 old ones are removed from the bottom if necessary to maintain this maximum
 length.
+.It Ic default-terminal Ar terminal
+Set the default terminal for new windows created in this session - the
+default value of the
+.Ev TERM
+environment variable.
+For
+.Nm
+to work correctly, this
+.Em must
+be set to
+.Ql screen ,
+.Ql tmux
+or a derivative of them.
 .It Ic escape-time Ar time
 Set the time in milliseconds for which
 .Nm
@@ -2405,18 +2418,6 @@ or
 This option should be configured when
 .Nm
 is used as a login shell.
-.It Ic default-terminal Ar terminal
-Set the default terminal for new windows created in this session - the
-default value of the
-.Ev TERM
-environment variable.
-For
-.Nm
-to work correctly, this
-.Em must
-be set to
-.Ql screen
-or a derivative of it.
 .It Xo Ic destroy-unattached
 .Op Ic on | off
 .Xc
diff --git a/tty.c b/tty.c
index ee52d038..f6db8e20 100644
--- a/tty.c
+++ b/tty.c
@@ -34,6 +34,7 @@
 void	tty_read_callback(struct bufferevent *, void *);
 void	tty_error_callback(struct bufferevent *, short, void *);
 
+void	tty_set_italics(struct tty *);
 int	tty_try_256(struct tty *, u_char, const char *);
 
 void	tty_colours(struct tty *, const struct grid_cell *);
@@ -457,6 +458,21 @@ tty_putn(struct tty *tty, const void *buf, size_t len, u_int width)
 }
 
 void
+tty_set_italics(struct tty *tty)
+{
+	const char	*s;
+
+	if (tty_term_has(tty->term, TTYC_SITM)) {
+		s = options_get_string(&global_options, "default-terminal");
+		if (strcmp(s, "screen") != 0 && strncmp(s, "screen-", 7) != 0) {
+			tty_putcode(tty, TTYC_SITM);
+			return;
+		}
+	}
+	tty_putcode(tty, TTYC_SMSO);
+}
+
+void
 tty_set_title(struct tty *tty, const char *title)
 {
 	if (!tty_term_has(tty->term, TTYC_TSL) ||
@@ -1396,12 +1412,8 @@ tty_attributes(struct tty *tty, const struct grid_cell *gc,
 		tty_putcode(tty, TTYC_BOLD);
 	if (changed & GRID_ATTR_DIM)
 		tty_putcode(tty, TTYC_DIM);
-	if (changed & GRID_ATTR_ITALICS) {
-		if (tty_term_has(tty->term, TTYC_SITM))
-			tty_putcode(tty, TTYC_SITM);
-		else
-			tty_putcode(tty, TTYC_SMSO);
-	}
+	if (changed & GRID_ATTR_ITALICS)
+		tty_set_italics(tty);
 	if (changed & GRID_ATTR_UNDERSCORE)
 		tty_putcode(tty, TTYC_SMUL);
 	if (changed & GRID_ATTR_BLINK)