locktime-blocks: rename to watchtime-blocks.

And clarify the descriptions for end users.

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

doc/lightningd-config.5.txt

@@ -150,15 +150,16 @@ Lightning node customization options:
 
 Lightning channel and HTLC options:
 
-*locktime-blocks*='BLOCKS'::
-    How long we need to spot an outdated close attempt, which is also
-    how long the peer would need to wait if they perform a unilateral
-    close.
+*watchtime-blocks*='BLOCKS'::
+    How long we need to spot an outdated close attempt: on opening a channel
+    we tell our peer that this is how long they'll have to wait if they perform
+    a unilateral close.
 
 *max-locktime-blocks*='BLOCKS'::
-    The longest we'll ever allow a peer to hold up payments, in the worst
-    case.  If they ask for longer, we'll refuse to create a channel,
-    and if an HTLC asks for longer, we'll refuse it.
+    The longest our funds can be delayed (ie. the longest *watchtime-blocks*
+    our peer can ask for, and also the longest HTLC timeout we will accept).
+    If our peer asks for longer, we'll refuse to create a channel, and if an
+    HTLC asks for longer, we'll refuse it.
 
 *funding-confirms*='BLOCKS'::
     Confirmations required for the funding transaction when the other side

lightningd/options.c

@@ -298,6 +298,14 @@ static char *opt_set_anchor(const char *arg, u32 *u)
 	return opt_set_u32(arg, u);
 }
 
+static char *opt_set_locktime(const char *arg, u32 *u)
+{
+	if (!deprecated_apis)
+		return "--locktime-blocks is now --watchtime-blocks";
+
+	return opt_set_u32(arg, u);
+}
+
 static void config_register_opts(struct lightningd *ld)
 {
 	opt_register_noarg("--daemon", opt_set_bool, &ld->daemon,
@@ -305,9 +313,11 @@ static void config_register_opts(struct lightningd *ld)
 	opt_register_arg("--ignore-fee-limits", opt_set_bool_arg, opt_show_bool,
 			 &ld->config.ignore_fee_limits,
 			 "(DANGEROUS) allow peer to set any feerate");
-	opt_register_arg("--locktime-blocks", opt_set_u32, opt_show_u32,
+	opt_register_arg("--watchtime-blocks", opt_set_u32, opt_show_u32,
 			 &ld->config.locktime_blocks,
 			 "Blocks before peer can unilaterally spend funds");
+	opt_register_arg("--locktime-blocks", opt_set_locktime, NULL,
+			 &ld->config.locktime_blocks, opt_hidden);
 	opt_register_arg("--max-locktime-blocks", opt_set_u32, opt_show_u32,
 			 &ld->config.locktime_max,
 			 "Maximum blocks a peer can lock up our funds");
@@ -891,7 +901,9 @@ static void add_config(struct lightningd *ld,
 			abort();
 		}
 	} else if (opt->type & OPT_HASARG) {
-		if (opt->show) {
+		if (opt->desc == opt_hidden) {
+			/* Ignore hidden options (deprecated) */
+		} else if (opt->show) {
 			char *buf = tal_arr(name0, char, OPT_SHOW_LEN+1);
 			opt->show(buf, opt->u.carg);
 

tests/test_lightningd.py

@@ -1286,7 +1286,7 @@ class LightningDTests(BaseLightningDTests):
 
     def test_bad_opening(self):
         # l1 asks for a too-long locktime
-        l1 = self.node_factory.get_node(options={'locktime-blocks': 100})
+        l1 = self.node_factory.get_node(options={'watchtime-blocks': 100})
         l2 = self.node_factory.get_node(options={'max-locktime-blocks': 99})
         ret = l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
 
@@ -1617,7 +1617,7 @@ class LightningDTests(BaseLightningDTests):
         disconnects = ['+WIRE_FUNDING_LOCKED', 'permfail']
         l1 = self.node_factory.get_node(disconnect=disconnects)
         # Make locktime different, as we once had them reversed!
-        l2 = self.node_factory.get_node(options={'locktime-blocks': 10})
+        l2 = self.node_factory.get_node(options={'watchtime-blocks': 10})
 
         l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
 
@@ -1701,7 +1701,7 @@ class LightningDTests(BaseLightningDTests):
     @unittest.skipIf(not DEVELOPER, "needs DEVELOPER=1")
     def test_onchaind_replay(self):
         disconnects = ['+WIRE_REVOKE_AND_ACK', 'permfail']
-        options = {'locktime-blocks': 201, 'cltv-delta': 101}
+        options = {'watchtime-blocks': 201, 'cltv-delta': 101}
         l1 = self.node_factory.get_node(options=options, disconnect=disconnects)
         l2 = self.node_factory.get_node(options=options)
 
@@ -3624,7 +3624,7 @@ class LightningDTests(BaseLightningDTests):
         # Previous runs with same bitcoind can leave funds!
         l1 = self.node_factory.get_node(random_hsm=True)
         max_locktime = 5 * 6 * 24
-        l2 = self.node_factory.get_node(options={'locktime-blocks': max_locktime + 1})
+        l2 = self.node_factory.get_node(options={'watchtime-blocks': max_locktime + 1})
         l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
 
         funds = 1000000
@@ -3643,7 +3643,7 @@ class LightningDTests(BaseLightningDTests):
         assert l2.rpc.listpeers()['peers'][0]['connected']
 
         # Restart l2 without ridiculous locktime.
-        del l2.daemon.opts['locktime-blocks']
+        del l2.daemon.opts['watchtime-blocks']
         l2.restart()
         l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
 

tests/utils.py

@@ -22,7 +22,7 @@ LIGHTNINGD_CONFIG = {
     "log-level": "debug",
     "cltv-delta": 6,
     "cltv-final": 5,
-    "locktime-blocks": 5,
+    "watchtime-blocks": 5,
     "rescan": 1,
 }