gossipd: fix false memleak positive in gossmap_manage

If there are pending channel announcements, they'll look like a leak unless we scan into
the maps.

```
lightningd-2 2025-05-01T07:27:03.922Z **BROKEN** gossipd: MEMLEAK: 0x60d000000478
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:   label=gossipd/gossmap_manage.c:595:struct pending_cannounce
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:   alloc:
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/ccan/ccan/tal/tal.c:488 (tal_alloc_)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/gossipd/gossmap_manage.c:595 (gossmap_manage_channel_announcement)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/gossipd/gossipd.c:205 (handle_recv_gossip)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/gossipd/gossipd.c:300 (connectd_req)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/common/daemon_conn.c:35 (handle_read)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/ccan/ccan/io/io.c:60 (next_plan)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/ccan/ccan/io/io.c:422 (do_plan)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/ccan/ccan/io/io.c:439 (io_ready)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/ccan/ccan/io/poll.c:455 (io_loop)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     /home/runner/work/lightning/lightning/gossipd/gossipd.c:660 (main)
lightningd-2 2025-05-01T07:27:03.923Z **BROKEN** gossipd:     ../sysdeps/nptl/libc_start_call_main.h:58 (__libc_start_call_main)
lightningd-2 2025-05-01T07:27:03.924Z **BROKEN** gossipd:     ../csu/libc-start.c:392 (__libc_start_main_impl)
lightningd-2 2025-05-01T07:27:03.924Z **BROKEN** gossipd:   parents:
lightningd-2 2025-05-01T07:27:03.924Z **BROKEN** gossipd:     gossipd/gossmap_manage.c:475:struct gossmap_manage
```

Signed-off-by: Rusty Russell <[email protected]>

Author: rustyrussell

gossipd/gossipd.c

@@ -479,6 +479,7 @@ static void dev_gossip_memleak(struct daemon *daemon, const u8 *msg)
 	memleak_scan_obj(memtable, daemon);
 	memleak_scan_htable(memtable, &daemon->peers->raw);
 	dev_seeker_memleak(memtable, daemon->seeker);
+	gossmap_manage_memleak(memtable, daemon->gm);
 
 	found_leak = dump_memleak(memtable, memleak_status_broken, NULL);
 	daemon_conn_send(daemon->master,

gossipd/gossmap_manage.c

@@ -6,6 +6,7 @@
 #include <common/daemon_conn.h>
 #include <common/gossip_store.h>
 #include <common/gossmap.h>
+#include <common/memleak.h>
 #include <common/status.h>
 #include <common/timeout.h>
 #include <common/wire_error.h>
@@ -469,6 +470,13 @@ static bool setup_gossmap(struct gossmap_manage *gm,
 	return true;
 }
 
+void gossmap_manage_memleak(struct htable *memtable,
+			    const struct gossmap_manage *gm)
+{
+	memleak_scan_uintmap(memtable, &gm->pending_ann_map.map);
+	memleak_scan_uintmap(memtable, &gm->early_ann_map.map);
+}
+
 struct gossmap_manage *gossmap_manage_new(const tal_t *ctx,
 					  struct daemon *daemon)
 {

gossipd/gossmap_manage.h

@@ -111,4 +111,7 @@ void gossmap_manage_tell_lightningd_locals(struct daemon *daemon,
  * The seeker uses this if we're at startup and want complete gossip.
  */
 bool gossmap_manage_populated(const struct gossmap_manage *gm);
+
+/* For memleak to see inside of maps */
+void gossmap_manage_memleak(struct htable *memtable, const struct gossmap_manage *gm);
 #endif /* LIGHTNING_GOSSIPD_GOSSMAP_MANAGE_H */