pkg/cover: always hide empty dirs

The last filtering step is the empty dirs removal.

2 files changed, 24 insertions, 6 deletions

diff --git a/pkg/cover/heatmap.go b/pkg/cover/heatmap.go
index 419a9a500..e6458c36b 100644
--- a/pkg/cover/heatmap.go
+++ b/pkg/cover/heatmap.go
@@ -259,17 +259,23 @@ func DoSubsystemsHeatMapStyleBodyJS(
 }
 
 func FormatResult(thm *templateHeatmap, format Format) {
-	thm.Filter(func(row *templateHeatmapRow) bool {
-		if row.IsDir && len(row.Items) > 0 {
-			return true
-		}
-		return slices.Max(row.Covered)-row.Covered[len(row.Covered)-1] >= int64(format.FilterMinCoveredLinesDrop)
-	})
+	// Remove file coverage lines with drop less than a threshold.
+	if format.FilterMinCoveredLinesDrop > 0 {
+		thm.Filter(func(row *templateHeatmapRow) bool {
+			return row.IsDir ||
+				slices.Max(row.Covered)-row.Covered[len(row.Covered)-1] >= int64(format.FilterMinCoveredLinesDrop)
+		})
+	}
+	// Remove file coverage lines with zero coverage during the analysis period.
 	if format.DropCoveredLines0 {
 		thm.Filter(func(row *templateHeatmapRow) bool {
 			return slices.Max(row.Covered) > 0
 		})
 	}
+	// Drop empty dir elements.
+	thm.Filter(func(row *templateHeatmapRow) bool {
+		return !row.IsDir || len(row.Items) > 0
+	})
 	// The files are sorted lexicographically by default.
 	if format.OrderByCoveredLinesDrop {
 		thm.Sort(func(row1 *templateHeatmapRow, row2 *templateHeatmapRow) int {
diff --git a/pkg/cover/heatmap_test.go b/pkg/cover/heatmap_test.go
index 1c094f1dd..e4b490f23 100644
--- a/pkg/cover/heatmap_test.go
+++ b/pkg/cover/heatmap_test.go
@@ -179,6 +179,11 @@ func TestFormatResult(t *testing.T) {
 									Covered: []int64{0, 0},
 									Depth:   1,
 								},
+								{
+									Name:    "file2",
+									Covered: []int64{1, 0},
+									Depth:   1,
+								},
 							},
 							Name:    "dir",
 							Covered: []int64{1, 0},
@@ -193,6 +198,13 @@ func TestFormatResult(t *testing.T) {
 				Root: &templateHeatmapRow{
 					Items: []*templateHeatmapRow{
 						{
+							Items: []*templateHeatmapRow{
+								{
+									Name:    "file2",
+									Covered: []int64{1, 0},
+									Depth:   1,
+								},
+							},
 							Name:    "dir",
 							Covered: []int64{1, 0},
 							IsDir:   true,