systemctl: warning about missing install info for template units

The advice string didn't talk about template units at all. Extend
it and print when trying to enable a template unit without install info.

Fixes #2345.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/shared/install.c b/src/shared/install.c
index febe33ed7b..71012eafb4 100644
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -1466,8 +1466,10 @@ static int install_info_symlink_link(
         assert(i->path);
 
         r = in_search_path(paths, i->path);
-        if (r != 0)
+        if (r < 0)
                 return r;
+        if (r > 0)
+                return 0;
 
         path = strjoin(config_path, "/", i->name, NULL);
         if (!path)
@@ -1506,7 +1508,8 @@ static int install_info_apply(
                 r = q;
 
         q = install_info_symlink_link(i, paths, config_path, force, changes, n_changes);
-        if (r == 0)
+        /* Do not count links to the unit file towards the "carries_install_info" count */
+        if (r == 0 && q < 0)
                 r = q;
 
         return r;