Fix S3 ListObjectsV2 recursion issue (#8347)

* Fix S3 ListObjectsV2 recursion issue (#8346)

Removed aggressive Limit=1 optimization in doListFilerEntries that caused missed directory entries when prefix ended with a delimiter. Added regression tests to verify deep directory traversal.

* Address PR comments: condense test comments

weed/s3api/s3api_object_handlers_list.go

@@ -520,9 +520,6 @@ func (s3a *S3ApiServer) doListFilerEntries(client filer_pb.SeaweedFilerClient, d
 		StartFromFileName:  marker,
 		InclusiveStartFrom: inclusiveStartFrom,
 	}
-	if cursor.prefixEndsOnDelimiter {
-		request.Limit = uint32(1)
-	}
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()

weed/s3api/s3api_object_handlers_list_test.go

@@ -55,6 +55,12 @@ func (c *testFilerClient) ListEntries(ctx context.Context, in *filer_pb.ListEntr
 		}
 		entries = filtered
 	}
+
+	// Respect Limit
+	if in.Limit > 0 && int(in.Limit) < len(entries) {
+		entries = entries[:in.Limit]
+	}
+
 	return &testListEntriesStream{entries: entries}, nil
 }
 
@@ -594,3 +600,83 @@ func TestObjectLevelListPermissions(t *testing.T) {
 	t.Log("Object-level List permissions like 'List:bucket/prefix/*' now work correctly")
 	t.Log("Middleware properly extracts prefix for permission validation")
 }
+
+func TestListObjectsV2_Regression(t *testing.T) {
+	// Reproduce issue: ListObjectsV2 without delimiter returns 0 objects even though files exist
+	// Structure: s3://reports/reports/[timestamp]/file
+	// Request: ListObjectsV2(Bucket='reports', Prefix='reports/')
+
+	s3a := &S3ApiServer{}
+	client := &testFilerClient{
+		entriesByDir: map[string][]*filer_pb.Entry{
+			"/buckets/reports": {
+				{Name: "reports", IsDirectory: true, Attributes: &filer_pb.FuseAttributes{}},
+			},
+			"/buckets/reports/reports": {
+				{Name: "01771152617961894200", IsDirectory: true, Attributes: &filer_pb.FuseAttributes{}},
+			},
+			"/buckets/reports/reports/01771152617961894200": {
+				{Name: "file1", IsDirectory: false, Attributes: &filer_pb.FuseAttributes{}},
+			},
+		},
+	}
+
+	// s3.list_objects_v2(Bucket='reports', Prefix='reports/')
+	// normalized: requestDir="", prefix="reports"
+	// doListFilerEntries called with dir="/buckets/reports", prefix="reports", delimiter=""
+
+	cursor := &ListingCursor{maxKeys: 1000, prefixEndsOnDelimiter: true} // set based on "reports/" original prefix
+	var results []string
+
+	// Call doListFilerEntries directly to unit test listing logic in isolation,
+	// simulating parameters passed from listFilerEntries for prefix "reports/".
+
+	_, err := s3a.doListFilerEntries(client, "/buckets/reports", "reports", cursor, "", "", false, "reports", func(dir string, entry *filer_pb.Entry) {
+		if !entry.IsDirectory {
+			results = append(results, entry.Name)
+		}
+	})
+
+	assert.NoError(t, err)
+	assert.Contains(t, results, "file1", "Should return the nested file")
+}
+
+func TestListObjectsV2_Regression_Sorting(t *testing.T) {
+	// Verify that listing logic correctly finds the target directory even when
+	// other entries with a similar prefix are returned first by the filer,
+	// a scenario where the removed Limit=1 optimization would fail.
+
+	s3a := &S3ApiServer{}
+	client := &testFilerClient{
+		entriesByDir: map[string][]*filer_pb.Entry{
+			"/buckets/reports": {
+				{Name: "reports-archive", IsDirectory: true, Attributes: &filer_pb.FuseAttributes{}},
+				{Name: "reports", IsDirectory: true, Attributes: &filer_pb.FuseAttributes{}},
+			},
+			"/buckets/reports/reports": {
+				{Name: "01771152617961894200", IsDirectory: true, Attributes: &filer_pb.FuseAttributes{}},
+			},
+			"/buckets/reports/reports/01771152617961894200": {
+				{Name: "file1", IsDirectory: false, Attributes: &filer_pb.FuseAttributes{}},
+			},
+		},
+	}
+
+	// This cursor setup mimics what happens in listFilerEntries
+	cursor := &ListingCursor{maxKeys: 1000, prefixEndsOnDelimiter: true}
+	var results []string
+
+	// Without the fix, Limit=1 would cause the lister to stop after "reports-archive",
+	// missing the intended "reports" directory.
+
+	_, err := s3a.doListFilerEntries(client, "/buckets/reports", "reports", cursor, "", "", false, "reports", func(dir string, entry *filer_pb.Entry) {
+		if !entry.IsDirectory {
+			results = append(results, entry.Name)
+		}
+	})
+
+	assert.NoError(t, err)
+	// With Limit=1, this fails because it only sees "reports-archive"
+	// With fix, it sees both and processes "reports"
+	assert.Contains(t, results, "file1", "Should return the nested file even if 'reports' directory is not the first match")
+}