Tracing which stabilizer is taking effect

pkg/archive/zip.go

@@ -7,6 +7,7 @@ import (
 	"archive/zip"
 	"bytes"
 	"crypto/sha256"
+	"encoding/base64"
 	"encoding/hex"
 	"io"
 	"slices"
@@ -216,14 +217,22 @@ func StabilizeZip(zr *zip.Reader, zw *zip.Writer, opts StabilizeOpts) error {
 	}
 	mr := NewMutableReader(zr)
 	for _, s := range opts.Stabilizers {
+		var currentStabName string
+		originalArchiveHash := getArchiveHash(&mr)
 		switch s.(type) {
 		case ZipArchiveStabilizer:
+			currentStabName = s.(ZipArchiveStabilizer).Name
 			s.(ZipArchiveStabilizer).Stabilize(&mr)
 		case ZipEntryStabilizer:
+			currentStabName = s.(ZipEntryStabilizer).Name
 			for _, mf := range mr.File {
 				s.(ZipEntryStabilizer).Stabilize(mf)
 			}
 		}
+		newArchiveHash := getArchiveHash(&mr)
+		if originalArchiveHash != newArchiveHash {
+			println("Stabilizer taking effect:", currentStabName)
+		}
 	}
 	return mr.WriteTo(zw)
 }
@@ -252,3 +261,27 @@ func toZipCompatibleReader(r io.Reader) (io.ReaderAt, int64, error) {
 	}
 	return bytes.NewReader(b), int64(len(b)), nil
 }
+
+// Helper to compute SHA256 and encode as base64 (url encoding, no padding)
+func computeSHA256Base64(data []byte) string {
+	h := sha256.New()
+	h.Write(data)
+	sum := h.Sum(nil)
+	return base64.RawURLEncoding.EncodeToString(sum)
+}
+
+func getArchiveHash(zr *MutableZipReader) string {
+	var buf bytes.Buffer
+	for _, zf := range zr.File {
+		content, err := zf.Open()
+		if err != nil {
+			continue
+		}
+		data, err := io.ReadAll(content)
+		if err != nil {
+			continue
+		}
+		buf.Write(data)
+	}
+	return computeSHA256Base64(buf.Bytes())
+}