fix(package): dedup StampModTimes after rebase onto ad93b7df

PR #32162 (merged 2026-07-15) introduced its own StampModTimes
implementation in pkg/chart/v2/chart.go, causing a duplicate after
rebasing this branch.  Keep our version (UTC.Truncate normalization,
detailed Lock.Generated comment, nil guards) and remove the duplicate
from #32162.  Also remove a duplicate StampModTimes call that appeared
in action/package.go after the rebase.

Signed-off-by: Ilya Kiselev <kis-ilya-a@yandex.ru>

pkg/action/package.go

@@ -135,10 +135,6 @@ func (p *Package) Run(path string, _ map[string]any) (string, error) {
 		dest = p.Destination
 	}
 
-	if p.SourceDateEpoch != nil {
-		ch.StampModTimes(*p.SourceDateEpoch)
-	}
-
 	name, err := chartutil.Save(ch, dest)
 	if err != nil {
 		return "", fmt.Errorf("failed to save: %w", err)

pkg/chart/v2/chart.go

@@ -118,20 +118,28 @@ func (ch *Chart) Dependencies() []*Chart { return ch.dependencies }
 func (ch *Chart) StampModTimes(t time.Time) {
 	t = t.UTC().Truncate(time.Second)
 	ch.ModTime = t
-	ch.SchemaModTime = t
+	if len(ch.Schema) > 0 {
+		ch.SchemaModTime = t
+	}
 	if ch.Lock != nil {
 		ch.Lock.Generated = t
 	}
 	for _, f := range ch.Raw {
-		f.ModTime = t
+		if f != nil {
+			f.ModTime = t
+		}
 	}
 	for _, f := range ch.Templates {
-		f.ModTime = t
+		if f != nil {
+			f.ModTime = t
+		}
 	}
 	for _, f := range ch.Files {
-		f.ModTime = t
+		if f != nil {
+			f.ModTime = t
+		}
 	}
-	for _, dep := range ch.dependencies {
+	for _, dep := range ch.Dependencies() {
 		dep.StampModTimes(t)
 	}
 }
@@ -208,37 +216,6 @@ func (ch *Chart) CRDObjects() []CRD {
 	return crds
 }
 
-// StampModTimes sets timestamps on the chart (and dependencies) to epoch.
-// This is used for reproducible builds via SOURCE_DATE_EPOCH.
-func (ch *Chart) StampModTimes(epoch time.Time) {
-	ch.ModTime = epoch
-	if len(ch.Schema) > 0 {
-		ch.SchemaModTime = epoch
-	}
-	if ch.Lock != nil {
-		ch.Lock.Generated = epoch
-	}
-
-	for _, f := range ch.Raw {
-		if f != nil {
-			f.ModTime = epoch
-		}
-	}
-	for _, f := range ch.Templates {
-		if f != nil {
-			f.ModTime = epoch
-		}
-	}
-	for _, f := range ch.Files {
-		if f != nil {
-			f.ModTime = epoch
-		}
-	}
-	for _, dep := range ch.Dependencies() {
-		dep.StampModTimes(epoch)
-	}
-}
-
 func hasManifestExtension(fname string) bool {
 	ext := filepath.Ext(fname)
 	return strings.EqualFold(ext, ".yaml") || strings.EqualFold(ext, ".yml") || strings.EqualFold(ext, ".json")