build: valid SOURCE_DATE_EPOCH

pkg/build/build.go

@@ -1196,6 +1196,9 @@ func sourceDateEpoch(defaultTime time.Time) (time.Time, error) {
 		// SHOULD exit with a non-zero error code.
 		return defaultTime, fmt.Errorf("failed to parse SOURCE_DATE_EPOCH: %w", err)
 	}
+	if sec < 315532800 {
+		return defaultTime, fmt.Errorf("SOURCE_DATE_EPOCH prior to 1980-01-01 12:00:00 not supported: %v", sec)
+	}
 
 	return time.Unix(sec, 0).UTC(), nil
 }

pkg/build/build_test.go

@@ -343,10 +343,10 @@ func TestSourceDateEpoch(t *testing.T) {
 			want:        time.Unix(1234567890, 0),
 		},
 		{
-			name:            "0",
-			sourceDateEpoch: "0",
+			name:            "Min time",
+			sourceDateEpoch: "315532800",
 			defaultTime:     time.Unix(1234567890, 0),
-			want:            time.Unix(0, 0),
+			want:            time.Unix(315532800, 0),
 		},
 		{
 			name:            "1234567890",
@@ -369,12 +369,12 @@ func TestSourceDateEpoch(t *testing.T) {
 			got, err := sourceDateEpoch(tt.defaultTime)
 			if err != nil {
 				if !tt.wantErr {
-					t.Fatalf("SourceDateEpoch() error = %v, wantErr %v", err, tt.wantErr)
+					t.Fatalf("%s: SourceDateEpoch() error = %v, wantErr %v", tt.name, err, tt.wantErr)
 				}
 				return
 			}
 			if !got.Equal(tt.want) {
-				t.Errorf("SourceDateEpoch() = %v, want %v", got, tt.want)
+				t.Errorf("%s: SourceDateEpoch() = %v, want %v", tt.name, got, tt.want)
 			}
 		})
 	}

pkg/build/options.go

@@ -58,7 +58,7 @@ func WithBuildDate(s string) Option {
 	return func(bc *Build) error {
 		// default to 0 for reproducibility
 		if s == "" {
-			bc.SourceDateEpoch = time.Unix(0, 0)
+			bc.SourceDateEpoch = time.Unix(315532800, 0)
 			return nil
 		}
 

pkg/build/pipelines/git-checkout.yaml

@@ -62,7 +62,7 @@ pipeline:
       process_cherry_picks() {
         local cpicksf="$1" oifs="$IFS" count=0
         local fetched_branches=""
-        local sdate=${SOURCE_DATE_EPOCH:-0}
+        local sdate=${SOURCE_DATE_EPOCH:-315532800}
         if [ "$sdate" -lt 315532800 ]; then
             msg "Setting commit date to Jan 1, 1980 (SOURCE_DATE_EPOCH found ${SOURCE_DATE_EPOCH})"
             sdate=315532800

pkg/build/sign_test.go

@@ -19,7 +19,7 @@ const MockName = "mockiavelli"
 
 func TestEmitSignature(t *testing.T) {
 	ctx := slogtest.Context(t)
-	sde := time.Unix(12345678, 0)
+	sde := time.Unix(1234567890, 0)
 
 	controlData := []byte("donkey")
 

pkg/cli/scan.go

@@ -148,7 +148,7 @@ func scanCmd(ctx context.Context, file string, sc *scanConfig) error {
 
 		bb := &build.Build{
 			WorkspaceDir:    dir,
-			SourceDateEpoch: time.Unix(0, 0),
+			SourceDateEpoch: time.Unix(315532800, 0),
 			Configuration:   *cfg,
 		}