roots: a joiner takes a root once its seeds named it

Review 3, R2: the root pin was set by the first HELLO_REPLY, and the
first sync, a round trip later, took that root; a peer naming another
afterwards was refused as another history. So the seed that answered
first decided, not "none while they disagree", and a malicious seed
makes itself fastest.

A node joining with an empty document of the first epoch now takes no
root (RootPin::Awaiting, roots left for later) until each of its seeds
named one, or ROOT_WAIT (10 s) passed since the first did; then the
one they name, none while they differ, as before. With --genesis-root
it takes that one alone, at once. access.md, the option's help and
example.toml say so; switching roots later, while the joiner holds
nothing of its own, is postponed.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/config/mod.rs b/src/config/mod.rs
index 572960b..34ed709 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -191,7 +191,7 @@ pub(crate) const OPTIONS: &[OptionSpec] = &[
         Kind::Text,
         "HASH",
         None,
-        "The hash of the swarm's genesis change (hex, as its genesis node logs it and GET /admin/epochs shows it): joining with an empty document, the only root this node takes. Without, the one its peers name, none while they name different ones (docs/access.md).",
+        "The hash of the swarm's genesis change (hex, as its genesis node logs it and GET /admin/epochs shows it): joining with an empty document, the only root this node takes. Without, the one its peers name once each seed named one or ten seconds passed since the first did, none while they name different ones (docs/access.md).",
     ),
     option(
         "strict-keys",