Quadlet: exit 0 when there are no files to process

Quadlet should not exit with failure if no files to process have been
found.  Otherwise, even simple operations such as reloading systemd
will fail as it retriggers generators.

Fixes: #17374
Signed-off-by: Valentin Rothberg <vrothberg@redhat.com>

cmd/quadlet/main.go

@@ -327,8 +327,10 @@ func main() {
 	}
 
 	if len(units) == 0 {
+		// containers/podman/issues/17374: exit cleanly but log that we
+		// had nothing to do
 		Debugf("No files to parse from %s", sourcePaths)
-		os.Exit(1)
+		os.Exit(0)
 	}
 
 	if !dryRun {

test/e2e/quadlet_test.go

@@ -365,7 +365,7 @@ var _ = Describe("quadlet system generator", func() {
 
 			session := podmanTest.Quadlet([]string{"-dryrun"}, "/something")
 			session.WaitWithDefaultTimeout()
-			Expect(session).Should(Exit(1))
+			Expect(session).Should(Exit(0))
 
 			current := session.ErrorToStringArray()
 			expected := "No files to parse from [/something]"