Remove unused second part of the expiry counter

internal/config/config_test.go

@@ -89,6 +89,29 @@ func TestFormatRoundTrips(t *testing.T) {
 	}
 }
 
+// The spellings themselves, not just their round trip: Duration.String() pads
+// out the units below the largest one, and trimming that tail is easy to get
+// wrong in a way that eats a real digit ("1m30s" must not become "1m3").
+func TestFormatDurationSpelling(t *testing.T) {
+	for _, c := range []struct {
+		in   time.Duration
+		want string
+	}{
+		{Unlimited, "never"},
+		{30 * time.Second, "30s"},
+		{time.Minute, "1m"},
+		{90 * time.Second, "1m30s"},
+		{90 * time.Minute, "1h30m"},
+		{2 * time.Hour, "2h"},
+		{25 * time.Hour, "25h"},
+		{72 * time.Hour, "3d"},
+	} {
+		if got := FormatDuration(c.in); got != c.want {
+			t.Errorf("FormatDuration(%s) = %q, want %q", c.in, got, c.want)
+		}
+	}
+}
+
 // The convention is: one hyphen for a letter, two for a word. It is enforced
 // here because the stdlib flag package treats both forms as the same.
 func TestHyphenConvention(t *testing.T) {

internal/config/parse.go

@@ -123,6 +123,13 @@ func FormatDuration(d time.Duration) string {
 	case d%time.Hour == 0:
 		return fmt.Sprintf("%dh", d/time.Hour)
 	default:
-		return d.String()
+		// Duration.String() spells out every unit below the largest one, so a
+		// whole number of minutes arrives as "1m0s". Drop that tail, but only
+		// when the seconds really are zero: "1m30s" has to keep them.
+		s := d.String()
+		if strings.HasSuffix(s, "m0s") {
+			s = strings.TrimSuffix(s, "0s")
+		}
+		return s
 	}
 }