freeing jsonrpc in shutdown cannot trigger db write's anymore

since PR ElementsProject#3867 utxos are unreserved by height, destroy_utxos and
related functions are not used anymore so clean them up also

TODO: Can test_stop_pending_fundchannel be removed ?

lightningd/lightningd.c

@@ -1194,13 +1194,6 @@ int main(int argc, char *argv[])
 	/* Tell plugins we're shutting down, closes the db for write access. */
 	shutdown_plugins(ld);
 
-	/* Clean up the JSON-RPC. This needs to happen in a DB transaction since
-	 * it might actually be touching the DB in some destructors, e.g.,
-	 * unreserving UTXOs (see #1737) */
-	db_begin_transaction(ld->wallet->db);
-	tal_free(ld->jsonrpc);
-	db_commit_transaction(ld->wallet->db);
-
 	/* Clean our our HTLC maps, since they use malloc. */
 	htlc_in_map_clear(&ld->htlcs_in);
 	htlc_out_map_clear(&ld->htlcs_out);

wallet/wallet.c

@@ -398,35 +398,8 @@ bool wallet_unreserve_output(struct wallet *w,
 					   OUTPUT_STATE_AVAILABLE);
 }
 
-/**
- * unreserve_utxo - Mark a reserved UTXO as available again
- */
-static void unreserve_utxo(struct wallet *w, const struct utxo *unres)
-{
-	if (!wallet_update_output_status(w, &unres->outpoint,
-					 OUTPUT_STATE_RESERVED,
-					 OUTPUT_STATE_AVAILABLE)) {
-		fatal("Unable to unreserve output");
-	}
-}
-
-/**
- * destroy_utxos - Destructor for an array of pointers to utxo
- */
-static void destroy_utxos(const struct utxo **utxos, struct wallet *w)
-{
-	for (size_t i = 0; i < tal_count(utxos); i++)
-		unreserve_utxo(w, utxos[i]);
-}
-
-void wallet_persist_utxo_reservation(struct wallet *w, const struct utxo **utxos)
-{
-	tal_del_destructor2(utxos, destroy_utxos, w);
-}
-
 void wallet_confirm_utxos(struct wallet *w, const struct utxo **utxos)
 {
-	tal_del_destructor2(utxos, destroy_utxos, w);
 	for (size_t i = 0; i < tal_count(utxos); i++) {
 		if (!wallet_update_output_status(
 			w, &utxos[i]->outpoint,

wallet/wallet.h

@@ -1411,13 +1411,6 @@ void add_unreleased_tx(struct wallet *w, struct unreleased_tx *utx);
 /* These will touch the db, so need to be explicitly freed. */
 void free_unreleased_txs(struct wallet *w);
 
-/* wallet_persist_utxo_reservation - Removes destructor
- *
- * Persists the reservation in the database (until a restart)
- * instead of clearing the reservation when the utxo object
- * is destroyed */
-void wallet_persist_utxo_reservation(struct wallet *w, const struct utxo **utxos);
-
 /* wallet_unreserve_output - Unreserve a utxo
  *
  * We unreserve utxos so that they can be spent elsewhere.