shared/install: avoid prematurely rejecting "missing" units

f7101b7368df copied some logic to prevent enabling masked units, but
also added a check which causes attempts to enable templated units to
fail. Since we know the logic beyond this check will properly handle
units which truly do not exist, we can rely on the unit file state
comparison to suffice for expressing the intent of f7101b7368df.

ref: https://bugs.archlinux.org/task/42616

diff --git a/src/shared/install.c b/src/shared/install.c
index 035b44c..cab93e8 100644 (file)
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -1620,12 +1620,10 @@ int unit_file_enable(
         STRV_FOREACH(i, files) {
                 UnitFileState state;
 
+                /* We only want to know if this unit is masked, so we ignore
+                 * errors from unit_file_get_state, deferring other checks.
+                 * This allows templated units to be enabled on the fly. */
                 state = unit_file_get_state(scope, root_dir, *i);
-                if (state < 0) {
-                        log_error("Failed to get unit file state for %s: %s", *i, strerror(-state));
-                        return state;
-                }
-
                 if (state == UNIT_FILE_MASKED || state == UNIT_FILE_MASKED_RUNTIME) {
                         log_error("Failed to enable unit: Unit %s is masked", *i);
                         return -ENOTSUP;