Change filesystem unit enumeration to use provided inputs (#4163)

Instead of recursively finding all files and emitting them as units, this
will simply pass the configured paths as units to the source.
Directories will get recursively chunked when scanned.

Author: mcastorina

pkg/sources/filesystem/filesystem.go

@@ -201,38 +201,16 @@ func (s *Source) scanFile(ctx context.Context, path string, chunksChan chan *sou
 // filepath or a directory.
 func (s *Source) Enumerate(ctx context.Context, reporter sources.UnitReporter) error {
 	for _, path := range s.paths {
-		fileInfo, err := os.Lstat(filepath.Clean(path))
+		_, err := os.Lstat(filepath.Clean(path))
 		if err != nil {
 			if err := reporter.UnitErr(ctx, err); err != nil {
 				return err
 			}
 			continue
 		}
-		if !fileInfo.IsDir() {
-			item := sources.CommonSourceUnit{ID: path}
-			if err := reporter.UnitOk(ctx, item); err != nil {
-				return err
-			}
-			continue
-		}
-		err = fs.WalkDir(os.DirFS(path), ".", func(relativePath string, d fs.DirEntry, err error) error {
-			if err != nil {
-				return reporter.UnitErr(ctx, err)
-			}
-			if d.IsDir() {
-				return nil
-			}
-			fullPath := filepath.Join(path, relativePath)
-			if s.filter != nil && !s.filter.Pass(fullPath) {
-				return nil
-			}
-			item := sources.CommonSourceUnit{ID: fullPath}
-			return reporter.UnitOk(ctx, item)
-		})
-		if err != nil {
-			if err := reporter.UnitErr(ctx, err); err != nil {
-				return err
-			}
+		item := sources.CommonSourceUnit{ID: path}
+		if err := reporter.UnitOk(ctx, item); err != nil {
+			return err
 		}
 	}
 	return nil