wallet: Add a final `CLOSED` state to channels

Instead of deleting the channels we will simple mark them as `CLOSED` from now
on. This is needed for some of the other tables not to end up with dangling
references that would otherwise survive the channel lifetime, e.g., forwards
and transactions.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

lightningd/channel_state.h

@@ -26,8 +26,11 @@ enum channel_state {
 	FUNDING_SPEND_SEEN,
 
 	/* On chain */
-	ONCHAIN
+	ONCHAIN,
+
+	/* Final state after we have fully settled on-chain */
+	CLOSED
 };
-#define CHANNEL_STATE_MAX ONCHAIN
+#define CHANNEL_STATE_MAX CLOSED
 
 #endif /* LIGHTNING_LIGHTNINGD_CHANNEL_STATE_H */

lightningd/peer_control.c

@@ -844,6 +844,9 @@ peer_connected_hook_cb(struct peer_connected_hook_payload *payload,
 		case CLOSINGD_COMPLETE:
 			/* Channel is supposed to be active!*/
 			abort();
+		case CLOSED:
+			/* Channel should not have been loaded */
+			abort();
 
 		/* We consider this "active" but we only send an error */
 		case AWAITING_UNILATERAL: {

wallet/wallet.c

@@ -850,8 +850,7 @@ bool wallet_channels_load_active(struct wallet *w)
 	sqlite3_stmt *stmt;
 
 	/* We load all channels */
-	stmt = db_select(w->db, "%s FROM channels;", channel_fields);
-
+	stmt = db_select(w->db, "%s FROM channels WHERE state < %d;", channel_fields, CLOSED);
 	w->max_channel_dbid = 0;
 
 	int count = 0;