revert +1 change to be on the safer side (#3972)

node/primitives/src/lib.rs

@@ -69,8 +69,7 @@ pub const POV_BOMB_LIMIT: usize = (MAX_POV_SIZE * 4u32) as usize;
 /// On Polkadot this is 1 day, and on Kusama it's 6 hours.
 ///
 /// Number of sessions we want to consider in disputes.
-/// + 1 for the child's session.
-pub const DISPUTE_WINDOW: SessionIndex = 6 + 1;
+pub const DISPUTE_WINDOW: SessionIndex = 6;
 
 /// The cumulative weight of a block in a fork-choice rule.
 pub type BlockWeight = u32;

node/subsystem-util/src/rolling_session_window.rs

@@ -289,7 +289,7 @@ mod tests {
 	use polkadot_primitives::v1::Header;
 	use sp_core::testing::TaskExecutor;
 
-	const TEST_WINDOW_SIZE: SessionIndex = 6 + 1;
+	const TEST_WINDOW_SIZE: SessionIndex = 6;
 
 	fn dummy_session_info(index: SessionIndex) -> SessionInfo {
 		SessionInfo {