Fix tail rows in portrait generation

internal/topdata/native.go

@@ -48,6 +48,7 @@ type nativeCollectedDataset struct {
 	LockData     map[string]int
 	RetiredKeys  map[string]struct{}
 	TableKey     string
+	DenseRowMax  int
 	LockAdded    int
 	LockPruned   int
 	LockModified bool
@@ -370,7 +371,7 @@ func buildNativeUnchecked(p *project.Project, opts NativeBuildOptions, progress
 		if err != nil {
 			return BuildResult{}, err
 		}
-		if err := write2DA(compiled, filepath.Join(output2DA, dataset.Dataset.OutputName), dataset.Dataset.Kind == nativeDatasetBase); err != nil {
+		if err := write2DA(compiled, filepath.Join(output2DA, dataset.Dataset.OutputName), dataset.Dataset.Kind == nativeDatasetBase, dataset.DenseRowMax); err != nil {
 			return BuildResult{}, err
 		}
 	}
@@ -1228,6 +1229,7 @@ func collectBaseDataset(dataset nativeDataset) (nativeCollectedDataset, error) {
 		Rows:         rows,
 		LockData:     lockData,
 		RetiredKeys:  retiredKeys,
+		DenseRowMax:  baseBoundaryID,
 		LockAdded:    lockAdded,
 		LockPruned:   lockPruned,
 		LockModified: lockModified,
@@ -5181,7 +5183,7 @@ func normalizeCollectedSpellImpactScripts(rows []map[string]any, baseRowKeys map
 	}
 }
 
-func write2DA(data map[string]any, path string, denseRows bool) error {
+func write2DA(data map[string]any, path string, denseRows bool, denseRowMax int) error {
 	columns, ok := data["columns"].([]string)
 	if !ok {
 		return fmt.Errorf("2da columns must be []string")
@@ -5223,6 +5225,17 @@ func write2DA(data map[string]any, path string, denseRows bool) error {
 			nextID = rowID + 1
 		}
 	}
+	if denseRows {
+		for nextID <= denseRowMax {
+			builder.WriteString(strconv.Itoa(nextID))
+			for range columns {
+				builder.WriteByte('\t')
+				builder.WriteString(nullValue)
+			}
+			builder.WriteByte('\n')
+			nextID++
+		}
+	}
 	return os.WriteFile(path, []byte(builder.String()), 0o644)
 }