fix: Use chart archive modifed time for OCI push

Signed-off-by: George Jenkins <gvjenkins@gmail.com>

pkg/pusher/ocipusher.go

@@ -90,8 +90,9 @@ func (pusher *OCIPusher) push(chartRef, href string) error {
 		path.Join(strings.TrimPrefix(href, fmt.Sprintf("%s://", registry.OCIScheme)), meta.Metadata.Name),
 		meta.Metadata.Version)
 
-	chartCreationTime := ctime.Created(stat)
-	pushOpts = append(pushOpts, registry.PushOptCreationTime(chartCreationTime.Format(time.RFC3339)))
+	// The time the chart was "created" is semantically the time the chart archive file was last written
+	chartArchiveFileCreatedTime := ctime.Modified(stat)
+	pushOpts = append(pushOpts, registry.PushOptCreationTime(chartArchiveFileCreatedTime.Format(time.RFC3339)))
 
 	_, err = client.Push(chartBytes, ref, pushOpts...)
 	return err

pkg/time/ctime/ctime.go

@@ -21,5 +21,9 @@ import (
 )
 
 func Created(fi os.FileInfo) time.Time {
-	return created(fi)
+	return modified(fi)
+}
+
+func Modified(fi os.FileInfo) time.Time {
+	return modified(fi)
 }

pkg/time/ctime/ctime_linux.go

@@ -23,8 +23,8 @@ import (
 	"time"
 )
 
-func created(fi os.FileInfo) time.Time {
+func modified(fi os.FileInfo) time.Time {
 	st := fi.Sys().(*syscall.Stat_t)
 	//nolint
-	return time.Unix(int64(st.Ctim.Sec), int64(st.Ctim.Nsec))
+	return time.Unix(int64(st.Mtim.Sec), int64(st.Mtim.Nsec))
 }

pkg/time/ctime/ctime_other.go

@@ -22,6 +22,6 @@ import (
 	"time"
 )
 
-func created(fi os.FileInfo) time.Time {
+func modified(fi os.FileInfo) time.Time {
 	return fi.ModTime()
 }