state: use INPUT_RVALUE instead of CMD_SEND_HTLC_FULFILL during closing.

We'd expect stop_commands to stop all commands, but we (ab)used
CMD_SEND_HTLC_FULFILL to send us R values even in closing state.

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

state.c

@@ -740,7 +740,7 @@ enum state state(const enum state state, const struct state_data *sdata,
 						 idata->cmd,
 						 BITCOIN_HTLC_RETURN_SPEND_DONE));
 				return state;
-			} else if (input_is(input, CMD_SEND_HTLC_FULFILL)) {
+			} else if (input_is(input, INPUT_RVALUE)) {
 				/* This gives us the r value. */
 				set_effect(effect, r_value,
 					   r_value_from_cmd(effect, sdata,
@@ -1060,8 +1060,8 @@ fail_during_close:
 						  BITCOIN_HTLC_TOTHEM_TIMEOUT);
 		/* Expect either close or spendthem to complete */
 		if (htlcs) {
-			/* FIXME: Make sure caller uses CMD_HTLC_FULFILL again
+			/* FIXME: Make sure caller uses INPUT_RVAL
-			 * if they were in the middle of one! */
+			 * if they were in the middle of FULFILL! */
 			set_effect(effect, watch_htlcs, htlcs);
 			return STATE_CLOSE_WAIT_SPENDTHEM_CLOSE_WITH_HTLCS;
 		}

state_types.h

@@ -257,7 +257,15 @@ enum state_input {
 	 * Timeouts.
 	 */
 	INPUT_CLOSE_COMPLETE_TIMEOUT,
-	
+
+	/*
+	 * Inject a known R value.
+	 *
+	 * In normal operation, use CMD_SEND_HTLC_FULFILL; this is for
+	 * after a unilateral close.
+	 */
+	INPUT_RVALUE,
+
 	/* Commands */
 	CMD_SEND_HTLC_UPDATE,
 	CMD_SEND_HTLC_FULFILL,

test/test_state_coverage.c

@@ -1019,6 +1019,7 @@ static struct trail *add_trail(enum state_input input,
 	t->before = *before;
 	t->after = *after;
 	if (input == CMD_SEND_HTLC_FULFILL
+	    || input == INPUT_RVALUE
 	    || input == BITCOIN_HTLC_TOTHEM_TIMEOUT
 	    || input == BITCOIN_HTLC_TOTHEM_SPENT
 	    || input == BITCOIN_HTLC_TOUS_TIMEOUT
@@ -1741,7 +1742,7 @@ static bool can_refire(enum state_input i)
 
 	/* They could have lots of htlcs. */
 	if (i == BITCOIN_HTLC_TOTHEM_SPENT || i == BITCOIN_HTLC_TOTHEM_TIMEOUT
-	    || i == BITCOIN_HTLC_TOUS_TIMEOUT || i == CMD_SEND_HTLC_FULFILL)
+	    || i == BITCOIN_HTLC_TOUS_TIMEOUT)
 		return true;
 
 	/* We manually remove these if they're not watching any more spends */
@@ -1870,7 +1871,7 @@ static struct trail *run_peer(const struct state_data *sdata,
 		idata->htlc = (struct htlc *)&copy.live_htlcs_to_us[i];
 		/* Only send this once. */
 		if (!rval_known(sdata, idata->htlc->id)) {
-			t = try_input(&copy, CMD_SEND_HTLC_FULFILL,
+			t = try_input(&copy, INPUT_RVALUE,
 				      idata, normalpath, errorpath,
 				      depth, hist);
 			if (t)