misc/getfiles: fix zst fallback

The previous symlink recursion fix broke the fallback for zst by
returning early.

Fixes 7a07a16ecb

Part-of: https://gitlab.postmarketos.org/postmarketOS/postmarketos-mkinitfs/-/merge_requests/67
[ci:skip-build]: already built successfully in CI

internal/misc/getfiles.go

@@ -47,14 +47,14 @@ func getFile(file string, required bool) (files []string, err error) {
 	// 2) set file to dereferenced target
 	// 4) continue this function to either walk it if the target is a dir or add the
 	// target to the list of files
-	if s, err := os.Lstat(file); err != nil {
-		return files, err
-	} else if s.Mode()&fs.ModeSymlink != 0 {
-		files = append(files, file)
-		if target, err := filepath.EvalSymlinks(file); err != nil {
-			return files, err
-		} else {
-			file = target
+	if s, err := os.Lstat(file); err == nil {
+		if s.Mode()&fs.ModeSymlink != 0 {
+			files = append(files, file)
+			if target, err := filepath.EvalSymlinks(file); err != nil {
+				return files, err
+			} else {
+				file = target
+			}
 		}
 	}
 

internal/misc/getfiles_test.go

@@ -107,6 +107,24 @@ func TestGetFile(t *testing.T) {
 			},
 			required: true,
 		},
+		{
+			name: "zst compressed file fallback",
+			setup: func(tmpDir string) (string, []string, error) {
+				// Create a .zst file but NOT the original file
+				zstFile := filepath.Join(tmpDir, "firmware.bin.zst")
+				if err := os.WriteFile(zstFile, []byte("compressed content"), 0644); err != nil {
+					return "", nil, err
+				}
+
+				// Request the original file (without .zst extension)
+				originalFile := filepath.Join(tmpDir, "firmware.bin")
+
+				// Expected: should find and return the .zst version
+				expected := []string{zstFile}
+				return originalFile, expected, nil
+			},
+			required: true,
+		},
 	}
 
 	for _, st := range subtests {