Don't reset the activity timer for unattached sessions every second,

this screws up the choice of most-recently-used. Instead, break the time
update into a little function and do it when the session is attached.

Pointed out by joshe@.

cmd-attach-session.c

@@ -74,6 +74,7 @@ cmd_attach_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 		}
 
 		ctx->curclient->session = s;
+		session_update_activity(s);
 		server_redraw_client(ctx->curclient);
 	} else {
 		if (!(ctx->cmdclient->flags & CLIENT_TERMINAL)) {
@@ -96,6 +97,7 @@ cmd_attach_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 			server_write_session(s, MSG_DETACH, NULL, 0);
 
 		ctx->cmdclient->session = s;
+		session_update_activity(s);
 		server_write_client(ctx->cmdclient, MSG_READY, NULL, 0);
 
 		update = options_get_string(&s->options, "update-environment");

cmd-new-session.c

@@ -284,12 +284,14 @@ cmd_new_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 			if (old_s != NULL)
 				ctx->cmdclient->last_session = old_s;
 			ctx->cmdclient->session = s;
+			session_update_activity(s);
 			server_redraw_client(ctx->cmdclient);
 		} else {
 			old_s = ctx->curclient->session;
 			if (old_s != NULL)
 				ctx->curclient->last_session = old_s;
 			ctx->curclient->session = s;
+			session_update_activity(s);
 			server_redraw_client(ctx->curclient);
 		}
 	}

cmd-switch-client.c

@@ -173,6 +173,7 @@ cmd_switch_client_exec(struct cmd *self, struct cmd_ctx *ctx)
 	if (c->session != NULL)
 		c->last_session = c->session;
 	c->session = s;
+	session_update_activity(s);
 
 	recalculate_sizes();
 	server_check_unattached();

server-client.c

@@ -761,11 +761,8 @@ server_client_msg_dispatch(struct client *c)
 
 			if (gettimeofday(&c->activity_time, NULL) != 0)
 				fatal("gettimeofday");
-			if (c->session != NULL) {
-				memcpy(&c->session->activity_time,
-				    &c->activity_time,
-				    sizeof c->session->activity_time);
-			}
+			if (c->session != NULL)
+				session_update_activity(c->session);
 
 			tty_start_tty(&c->tty);
 			server_redraw_client(c);

server-fn.c

@@ -396,6 +396,7 @@ server_destroy_session(struct session *s)
 		} else {
 			c->last_session = NULL;
 			c->session = s_new;
+			session_update_activity(s_new);
 			server_redraw_client(c);
 		}
 	}

server.c

@@ -494,12 +494,8 @@ server_lock_server(void)
 
 	t = time(NULL);
 	RB_FOREACH(s, sessions, &sessions) {
-		if (s->flags & SESSION_UNATTACHED) {
-			if (gettimeofday(&s->activity_time, NULL) != 0)
-				fatal("gettimeofday failed");
+		if (s->flags & SESSION_UNATTACHED)
 			continue;
-		}
-
 		timeout = options_get_number(&s->options, "lock-after-time");
 		if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout)
 			return;	/* not timed out */
@@ -519,12 +515,8 @@ server_lock_sessions(void)
 
 	t = time(NULL);
 	RB_FOREACH(s, sessions, &sessions) {
-		if (s->flags & SESSION_UNATTACHED) {
-			if (gettimeofday(&s->activity_time, NULL) != 0)
-				fatal("gettimeofday failed");
+		if (s->flags & SESSION_UNATTACHED)
 			continue;
-		}
-
 		timeout = options_get_number(&s->options, "lock-after-time");
 		if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
 			server_lock_session(s);

session.c

@@ -97,7 +97,7 @@ session_create(const char *name, const char *cmd, const char *cwd,
 
 	if (gettimeofday(&s->creation_time, NULL) != 0)
 		fatal("gettimeofday failed");
-	memcpy(&s->activity_time, &s->creation_time, sizeof s->activity_time);
+	session_update_activity(s);
 
 	s->cwd = xstrdup(cwd);
 
@@ -164,6 +164,14 @@ session_destroy(struct session *s)
 	RB_INSERT(sessions, &dead_sessions, s);
 }
 
+/* Update session active time. */
+void
+session_update_activity(struct session *s)
+{
+	if (gettimeofday(&s->activity_time, NULL) != 0)
+		fatal("gettimeofday");
+}
+
 /* Find the next usable session. */
 struct session *
 session_next_session(struct session *s)

tmux.h

@@ -1980,6 +1980,7 @@ struct session	*session_create(const char *, const char *, const char *,
 		     struct environ *, struct termios *, int, u_int, u_int,
 		     char **);
 void		 session_destroy(struct session *);
+void		 session_update_activity(struct session *);
 struct session	*session_next_session(struct session *);
 struct session	*session_previous_session(struct session *);
 struct winlink	*session_new(struct session *,