walletrpc: don't assert() when we pay ourselves.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tests/test_lightningd.py

@@ -2427,6 +2427,13 @@ class LightningDTests(BaseLightningDTests):
         c.execute('SELECT COUNT(*) FROM outputs WHERE status=0')
         assert(c.fetchone()[0] == 6)
 
+        # Test withdrawal to self.
+        out = l1.rpc.withdraw(l1.rpc.newaddr()['address'], 'all')
+        bitcoind.rpc.generate(1)
+        c = db.cursor()
+        c.execute('SELECT COUNT(*) FROM outputs WHERE status=0')
+        assert(c.fetchone()[0] == 1)
+        
         out = l1.rpc.withdraw(waddr, 'all')
         c = db.cursor()
         c.execute('SELECT COUNT(*) FROM outputs WHERE status=0')

wallet/walletrpc.c

@@ -58,7 +58,9 @@ static void wallet_withdrawal_broadcast(struct bitcoind *bitcoind,
 		tx = bitcoin_tx_from_hex(withdraw, withdraw->hextx, strlen(withdraw->hextx));
 		assert(tx != NULL);
 		wallet_extract_owned_outputs(ld->wallet, tx, &change_satoshi);
-		assert(change_satoshi == withdraw->changesatoshi);
+
+		/* Note normally, change_satoshi == withdraw->changesatoshi, but
+		 * not if we're actually making a payment to ourselves! */
 
 		struct json_result *response = new_json_result(cmd);
 		json_object_start(response, NULL);