usr/bin/byobu-launch, usr/bin/byobu-launcher-install: fix handling

of logout behavior, when dpkg-configured globally by the sysadmin,
LP: #741281

debian/changelog

@@ -10,6 +10,9 @@ byobu (3.30) unreleased; urgency=low
     LP: #760696
   * usr/bin/byobu-launcher: don't disrupt work flow, but rather inform
     user about launching byobu in a nested screen session, LP: #747649
+  * usr/bin/byobu-launch, usr/bin/byobu-launcher-install: fix handling
+    of logout behavior, when dpkg-configured globally by the sysadmin,
+    LP: #741281
 
   [ Chaskiel Grundman ]
   * debian/postinst: correctly fix old-school screen-profiles era diversions

usr/bin/byobu-launch

@@ -17,4 +17,7 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-case "$-" in *i*) byobu-launcher && exit 0; esac;
+PKG="byobu"
+DATA="$HOME/.$PKG"
+case "$-" in *i*) byobu-launcher; esac;
+[ -e "$DATA/no-logout-on-detach" ] || exit 0

usr/bin/byobu-launcher-install

@@ -20,6 +20,7 @@
 
 PKG="byobu"
 DATA="$HOME/.$PKG"
+FLAG="$DATA/no-logout-on-detach"
 
 LOGOUT_ON_DETACH=1
 for i in $@; do
@@ -30,6 +31,14 @@ for i in $@; do
 	esac
 done
 
+update_flag() {
+	if [ "$LOGOUT_ON_DETACH" = "1" ]; then
+		rm -f "$FLAG"
+	else
+		touch "$FLAG"
+	fi
+}
+
 install_launcher() {
 	if [ "$LOGOUT_ON_DETACH" = "1" ]; then
 		printf "%s\n" 'case "$-" in *i*) byobu-launcher && exit 0; esac;' >> "$1"
@@ -44,6 +53,9 @@ $PKG-launcher-uninstall || true
 touch "$HOME"/.hushlogin
 rm -f "$DATA/disable-autolaunch"
 
+# Update the logout/nologout flag
+update_flag
+
 # Handle bourne shells, if not set globally in /etc/profile.d
 if [ ! -h "/etc/profile.d/Z98-$PKG.sh" ]; then
 	# Install in $HOME/.profile unconditionally