s3api: fix bucket-root listing w/ delimiter (#7827)

* s3api: fix bucket-root listing w/ delimiter

* test: improve mock robustness for bucket-root listing test

- Make testListEntriesStream implement interface explicitly without embedding
- Add prefix filtering logic to testFilerClient to simulate real filer behavior
- Special-case prefix='/' to not filter for bucket root compatibility
- Add required imports for metadata and strings packages

This addresses review comments about test mock brittleness and accuracy.

* test: add clarifying comment for mock filtering behavior

Add detailed comment explaining which ListEntriesRequest parameters
are implemented (Prefix) vs ignored (Limit, StartFromFileName, etc.)
in the test mock to improve code documentation and future maintenance.

* logging

* less logs

* less check if already locked

weed/s3api/s3api_object_handlers_list.go

@@ -53,19 +53,16 @@ func (s3a *S3ApiServer) ListObjectsV2Handler(w http.ResponseWriter, r *http.Requ
 
 	// collect parameters
 	bucket, _ := s3_constants.GetBucketAndObject(r)
-	glog.V(3).Infof("ListObjectsV2Handler %s", bucket)
-
 	originalPrefix, startAfter, delimiter, continuationToken, encodingTypeUrl, fetchOwner, maxKeys, allowUnordered, errCode := getListObjectsV2Args(r.URL.Query())
 
+	glog.V(2).Infof("ListObjectsV2Handler bucket=%s prefix=%s", bucket, originalPrefix)
+
 	if errCode != s3err.ErrNone {
 		s3err.WriteErrorResponse(w, r, errCode)
 		return
 	}
 
-	if maxKeys < 0 {
-		s3err.WriteErrorResponse(w, r, s3err.ErrInvalidMaxKeys)
-		return
-	}
+	// maxKeys is uint16 here; negative values are rejected during parsing.
 
 	// AWS S3 compatibility: allow-unordered cannot be used with delimiter
 	if allowUnordered && delimiter != "" {
@@ -121,10 +118,10 @@ func (s3a *S3ApiServer) ListObjectsV1Handler(w http.ResponseWriter, r *http.Requ
 
 	// collect parameters
 	bucket, _ := s3_constants.GetBucketAndObject(r)
-	glog.V(3).Infof("ListObjectsV1Handler %s", bucket)
-
 	originalPrefix, marker, delimiter, encodingTypeUrl, maxKeys, allowUnordered, errCode := getListObjectsV1Args(r.URL.Query())
 
+	glog.V(2).Infof("ListObjectsV1Handler bucket=%s prefix=%s", bucket, originalPrefix)
+
 	if errCode != s3err.ErrNone {
 		s3err.WriteErrorResponse(w, r, errCode)
 		return
@@ -447,9 +444,8 @@ func (s3a *S3ApiServer) doListFilerEntries(client filer_pb.SeaweedFilerClient, d
 	//   prefix and marker should be under dir, marker may contain "/"
 	//   maxKeys should be updated for each recursion
 	// glog.V(4).Infof("doListFilerEntries dir: %s, prefix: %s, marker %s, maxKeys: %d, prefixEndsOnDelimiter: %+v", dir, prefix, marker, cursor.maxKeys, cursor.prefixEndsOnDelimiter)
-	if prefix == "/" && delimiter == "/" {
-		return
-	}
+	// When listing at bucket root with delimiter '/', prefix can be "/" after normalization.
+	// Returning early here would incorrectly hide all top-level entries (folders like "Veeam/").
 	if cursor.maxKeys <= 0 {
 		return // Don't set isTruncated here - let caller decide based on whether more entries exist
 	}
@@ -720,7 +716,6 @@ func (s3a *S3ApiServer) ensureDirectoryAllEmpty(filerClient filer_pb.SeaweedFile
 	return true, nil
 }
 
-
 // compareWithDelimiter compares two strings for sorting, treating the delimiter character
 // as having lower precedence than other characters to match AWS S3 behavior.
 // For example, with delimiter '/', 'foo/' should come before 'foo+1/' even though '+' < '/' in ASCII.

weed/s3api/s3api_object_handlers_list_test.go

@@ -1,14 +1,63 @@
 package s3api
 
 import (
+	"context"
+	"io"
 	"net/http/httptest"
+	"strings"
 	"testing"
 	"time"
 
+	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
 	"github.com/seaweedfs/seaweedfs/weed/s3api/s3err"
 	"github.com/stretchr/testify/assert"
+	grpc "google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
 )
 
+type testListEntriesStream struct {
+	entries []*filer_pb.Entry
+	idx     int
+}
+
+func (s *testListEntriesStream) Recv() (*filer_pb.ListEntriesResponse, error) {
+	if s.idx >= len(s.entries) {
+		return nil, io.EOF
+	}
+	resp := &filer_pb.ListEntriesResponse{Entry: s.entries[s.idx]}
+	s.idx++
+	return resp, nil
+}
+
+func (s *testListEntriesStream) Header() (metadata.MD, error) { return metadata.MD{}, nil }
+func (s *testListEntriesStream) Trailer() metadata.MD         { return metadata.MD{} }
+func (s *testListEntriesStream) Close() error                 { return nil }
+func (s *testListEntriesStream) Context() context.Context     { return context.Background() }
+func (s *testListEntriesStream) SendMsg(m interface{}) error  { return nil }
+func (s *testListEntriesStream) RecvMsg(m interface{}) error  { return nil }
+func (s *testListEntriesStream) CloseSend() error             { return nil }
+
+type testFilerClient struct {
+	filer_pb.SeaweedFilerClient
+	entriesByDir map[string][]*filer_pb.Entry
+}
+
+func (c *testFilerClient) ListEntries(ctx context.Context, in *filer_pb.ListEntriesRequest, opts ...grpc.CallOption) (grpc.ServerStreamingClient[filer_pb.ListEntriesResponse], error) {
+	entries := c.entriesByDir[in.Directory]
+	// Simplified mock: implements basic prefix filtering but ignores Limit, StartFromFileName, and InclusiveStartFrom
+	// to keep test logic focused. Prefix "/" is treated as no filter for bucket root compatibility.
+	if in.Prefix != "" && in.Prefix != "/" {
+		filtered := make([]*filer_pb.Entry, 0)
+		for _, e := range entries {
+			if strings.HasPrefix(e.Name, in.Prefix) {
+				filtered = append(filtered, e)
+			}
+		}
+		entries = filtered
+	}
+	return &testListEntriesStream{entries: entries}, nil
+}
+
 func TestListObjectsHandler(t *testing.T) {
 
 	// https://docs.aws.amazon.com/AmazonS3/latest/API/v2-RESTBucketGET.html
@@ -53,6 +102,13 @@ func Test_normalizePrefixMarker(t *testing.T) {
 		wantAlignedPrefix string
 		wantAlignedMarker string
 	}{
+		{"bucket root listing with delimiter",
+			args{"/",
+				""},
+			"",
+			"",
+			"",
+		},
 		{"prefix is a directory",
 			args{"/parentDir/data/",
 				""},
@@ -146,6 +202,31 @@ func TestAllowUnorderedParameterValidation(t *testing.T) {
 	})
 }
 
+func TestDoListFilerEntries_BucketRootPrefixSlashDelimiterSlash_ListsDirectories(t *testing.T) {
+	// Regression test for a bug where doListFilerEntries returned early when
+	// prefix == "/" && delimiter == "/", causing bucket-root folder listings
+	// (e.g. Veeam v13) to return empty results.
+
+	s3a := &S3ApiServer{}
+	client := &testFilerClient{
+		entriesByDir: map[string][]*filer_pb.Entry{
+			"/buckets/test-bucket": {
+				{Name: "Veeam", IsDirectory: true, Attributes: &filer_pb.FuseAttributes{}},
+			},
+		},
+	}
+
+	cursor := &ListingCursor{maxKeys: 1000}
+	seen := make([]string, 0)
+	_, err := s3a.doListFilerEntries(client, "/buckets/test-bucket", "/", cursor, "", "/", false, func(dir string, entry *filer_pb.Entry) {
+		if entry.IsDirectory {
+			seen = append(seen, entry.Name)
+		}
+	})
+	assert.NoError(t, err)
+	assert.Contains(t, seen, "Veeam")
+}
+
 func TestAllowUnorderedWithDelimiterValidation(t *testing.T) {
 	t.Run("should return error when allow-unordered=true and delimiter are both present", func(t *testing.T) {
 		// Create a request with both allow-unordered=true and delimiter

weed/s3api/s3api_object_handlers_put.go

@@ -76,7 +76,7 @@ func (s3a *S3ApiServer) PutObjectHandler(w http.ResponseWriter, r *http.Request)
 	// http://docs.aws.amazon.com/AmazonS3/latest/dev/UploadingObjects.html
 
 	bucket, object := s3_constants.GetBucketAndObject(r)
-	glog.V(3).Infof("PutObjectHandler %s %s", bucket, object)
+	glog.V(2).Infof("PutObjectHandler bucket=%s object=%s size=%d", bucket, object, r.ContentLength)
 
 	_, err := validateContentMd5(r.Header)
 	if err != nil {