storage: strip env specific data during archive

This ensures the checksum is predictable, and not influenced by e.g.
different runtime configuration settings, or FS specific data.

Signed-off-by: Hidde Beydals <hello@hidde.co>

controllers/gitrepository_controller_test.go

@@ -576,7 +576,7 @@ func TestGitRepositoryReconciler_reconcileArtifact(t *testing.T) {
 			},
 			afterFunc: func(t *WithT, obj *sourcev1.GitRepository, artifact sourcev1.Artifact) {
 				t.Expect(obj.GetArtifact()).ToNot(BeNil())
-				t.Expect(obj.GetArtifact().Checksum).To(Equal("f9955588f6aeed7be9b1ef15cd2ddac47bb53291"))
+				t.Expect(obj.GetArtifact().Checksum).To(Equal("b1fab897a1a0fb8094ce3ae0e9743a4b72bd7268"))
 			},
 			want: ctrl.Result{RequeueAfter: interval},
 			assertConditions: []metav1.Condition{
@@ -592,7 +592,7 @@ func TestGitRepositoryReconciler_reconcileArtifact(t *testing.T) {
 			},
 			afterFunc: func(t *WithT, obj *sourcev1.GitRepository, artifact sourcev1.Artifact) {
 				t.Expect(obj.GetArtifact()).ToNot(BeNil())
-				t.Expect(obj.GetArtifact().Checksum).To(Equal("542a8ad0171118a3249e8c531c598b898defd742"))
+				t.Expect(obj.GetArtifact().Checksum).To(Equal("a71f8c076db814bc21c16cecc960c4fcaf970ac5"))
 			},
 			want: ctrl.Result{RequeueAfter: interval},
 			assertConditions: []metav1.Condition{

controllers/storage.go

@@ -165,7 +165,8 @@ func SourceIgnoreFilter(ps []gitignore.Pattern, domain []string) ArchiveFileFilt
 }
 
 // Archive atomically archives the given directory as a tarball to the given v1beta1.Artifact path, excluding
-// directories and any ArchiveFileFilter matches.
+// directories and any ArchiveFileFilter matches. While archiving, any environment specific data (for example,
+// the user and group name) is stripped from file headers.
 // If successful, it sets the checksum and last update time on the artifact.
 func (s *Storage) Archive(artifact *sourcev1.Artifact, dir string, filter ArchiveFileFilter) (err error) {
 	if f, err := os.Stat(dir); os.IsNotExist(err) || !f.IsDir() {
@@ -220,6 +221,16 @@ func (s *Storage) Archive(artifact *sourcev1.Artifact, dir string, filter Archiv
 		}
 		header.Name = relFilePath
 
+		// We want to remove any environment specific data as well, this
+		// ensures the checksum is purely content based.
+		header.Gid = 0
+		header.Uid = 0
+		header.Uname = ""
+		header.Gname = ""
+		header.ModTime = time.Time{}
+		header.AccessTime = time.Time{}
+		header.ChangeTime = time.Time{}
+
 		if err := tw.WriteHeader(header); err != nil {
 			return err
 		}