fix: don't leak goroutines if there are no files to watch (#822)

configx/provider.go

@@ -142,8 +142,12 @@ func (p *Provider) createProviders(ctx context.Context) (providers []koanf.Provi
 	p.logger.WithField("files", paths).Debug("Adding config files.")
 
 	c := make(watcherx.EventChannel)
-	go p.watchForFileChanges(ctx, c)
 
+	defer func() {
+		if err == nil && len(paths) > 0 {
+			go p.watchForFileChanges(ctx, c)
+		}
+	}()
 	for _, path := range paths {
 		fp, err := NewKoanfFile(path)
 		if err != nil {

configx/provider_watch_test.go

@@ -49,11 +49,11 @@ func assertNoOpenFDs(t require.TestingT, dir, name string) {
 	}
 	var b, be bytes.Buffer
 	// we are only interested in the file descriptors, so we use the `-F f` option
-	c := exec.Command("lsof", "-n", "-F", "f", filepath.Join(dir, name))
+	c := exec.Command("lsof", "-n", "-F", "f", "--", filepath.Join(dir, name))
 	c.Stdout = &b
 	c.Stderr = &be
 	exitErr := new(exec.ExitError)
-	require.ErrorAs(t, c.Run(), &exitErr, "got stout: %s\nstderr: %s", b.String(), be.String())
+	require.ErrorAsf(t, c.Run(), &exitErr, "File %q has open file descriptor.\nGot stout: %s\nstderr: %s", filepath.Join(dir, name), b.String(), be.String())
 	assert.Equal(t, 1, exitErr.ExitCode(), "got stout: %s\nstderr: %s", b.String(), be.String())
 }