diff --git a/ccan/README b/ccan/README
index 82d4f2af3..fbec62415 100644
--- a/ccan/README
+++ b/ccan/README
@@ -1,3 +1,3 @@
 CCAN imported from http://ccodearchive.net.
 
-CCAN version: init-2500-gcbc7cbf1
+CCAN version: init-2502-gb45a3266
diff --git a/ccan/ccan/json_out/json_out.c b/ccan/ccan/json_out/json_out.c
index 87deaca85..53837e67c 100644
--- a/ccan/ccan/json_out/json_out.c
+++ b/ccan/ccan/json_out/json_out.c
@@ -337,11 +337,12 @@ char *json_out_direct(struct json_out *jout, size_t len)
 	return p;
 }
 
-void json_out_finished(const struct json_out *jout)
+void json_out_finished(struct json_out *jout)
 {
 #ifdef CCAN_JSON_OUT_DEBUG
 	assert(tal_count(jout->wrapping) == 0);
 #endif
+	jout->empty = true;
 }
 
 const char *json_out_contents(const struct json_out *jout, size_t *len)
diff --git a/ccan/ccan/json_out/json_out.h b/ccan/ccan/json_out/json_out.h
index 2911ff247..da8b4ffa7 100644
--- a/ccan/ccan/json_out/json_out.h
+++ b/ccan/ccan/json_out/json_out.h
@@ -177,9 +177,12 @@ bool json_out_add_splice(struct json_out *jout,
  * @jout: the json_out object written to.
  *
  * This simply causes internal assertions that all arrays and objects are
- * finished.  It needs CCAN_JSON_OUT_DEBUG defined to have any effect.
+ * finished. If CCAN_JSON_OUT_DEBUG is defined, it does sanity checks.
+ *
+ * This also resets the empty flag, so there will be no comma added if
+ * another JSON object is written.
  */
-void json_out_finished(const struct json_out *jout);
+void json_out_finished(struct json_out *jout);
 
 /**
  * json_out_contents - read contents from json_out stream.
diff --git a/ccan/ccan/opt/test/run-unregister.c b/ccan/ccan/opt/test/run-unregister.c
new file mode 100644
index 000000000..d2dc469bd
--- /dev/null
+++ b/ccan/ccan/opt/test/run-unregister.c
@@ -0,0 +1,43 @@
+#include <ccan/tap/tap.h>
+#include <stdlib.h>
+#include <ccan/opt/opt.c>
+#include <ccan/opt/usage.c>
+#include <ccan/opt/helpers.c>
+#include <ccan/opt/parse.c>
+#include "utils.h"
+
+int main(int argc, char *argv[])
+{
+	const char *myname = argv[0];
+
+	plan_tests(15);
+
+	opt_register_noarg("--aaa|-a", test_noarg, NULL, "AAAAAAll");
+	opt_register_arg("-b", test_arg, NULL, "bbb", "b");
+
+	/* We can't unregister wrong ones, but can unregister correct one */
+	ok1(!opt_unregister("--aaa"));
+	ok1(!opt_unregister("-a"));
+	ok1(opt_unregister("--aaa|-a"));
+
+	/* Arg parsing works as if we'd never registered it */
+	ok1(parse_args(&argc, &argv, "-bbbb", NULL));
+	ok1(argc == 1);
+	ok1(argv[0] == myname);
+	ok1(argv[1] == NULL);
+	ok1(test_cb_called == 1);
+
+	ok1(!parse_args(&argc, &argv, "--aaa", NULL));
+
+	/* We can still add another one OK. */
+	opt_register_noarg("-c", test_noarg, NULL, "AAAAAAll");
+	ok1(parse_args(&argc, &argv, "-c", NULL));
+	ok1(argc == 1);
+	ok1(argv[0] == myname);
+	ok1(argv[1] == NULL);
+	ok1(test_cb_called == 2);
+
+	/* parse_args allocates argv */
+	free(argv);
+	return exit_status();
+}