postgresql-setup: detect systemd's NeedDaemonReloadprep-1

Because we rely on parsing of `systemctl show -p` outuput heavily,
we need to detect whether the service file or some dropin did not
change (or was not added).  So from now we rather instruct admin
to do daemon-reload when something changed..

* postgresql-setup.in: Detect the NeedDaemonReload and warn if
yes.
* NEWS: Document.

2 files changed, 13 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index b49039b..08bb40a 100644
--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,10 @@ New in 0.9.2 version
   environment variable setup from systemd's environment files specified
   via EnvironmentFile= statement (reminded by private rhbz#1135611).
 
+* postgresql-setup now detects whether systemd configuration changed
+  while the `systemctl daemon-reload` was not done yet.  Without
+  daemon-reload, running postgresql-setup could lead to unexpected results.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 New in 0.9.1 version
diff --git a/postgresql-setup.in b/postgresql-setup.in
index bd47f98..bbb1863 100644
--- a/postgresql-setup.in
+++ b/postgresql-setup.in
@@ -515,6 +515,15 @@ export PGPORT=$pgport
 debug "final pgdata: $pgdata"
 debug "final pgport: $pgport"
 
+nr_option=NeedDaemonReload
+nr_out="`systemctl show -p $nr_option $option_service.service 2>/dev/null`"
+if [[ "$nr_out" != "$nr_option=no" ]]; then
+    error   $"Note that systemd configuration for '$option_service' changed."
+    error_q $"You need to perform 'systemctl daemon-reload' otherwise the"
+    error_q $"results of this script can be inadequate."
+    exit 1
+fi
+
 script_result=0
 
 # See how we were called.