fix(relay): refuse a second listed open channel with the same name

NOSTR.md

@@ -50,10 +50,10 @@ PGPASSWORD=buzz_dev psql -h localhost -U buzz -d buzz -c \
 | **Reactions (kind:7)** | ✅ | Standard NIP-25; channel derived from target event's `#e` tag (client `#h` ignored) |
 | **Deletions (kind:5)** | ✅ | Standard NIP-09; self-authored only. `#h` optional, `#e` required |
 | **User profiles (kind:0)** | ✅ | NIP-01 metadata; synced to users table (display_name, avatar, about, NIP-05). NIP-05 handles must canonicalize to this relay's domain — off-domain or invalid handles are silently cleared. If a NIP-05 handle collides with another user's (UNIQUE constraint), the handle is skipped but other profile fields (display_name, avatar, about) are still synced. |
-| **Group creation (kind:9007)** | ✅ | NIP-29; include `name` tag, optional `visibility`, `channel_type`, label `t` and `unlisted` tags |
+| **Group creation (kind:9007)** | ✅ | NIP-29; include an `h` tag with the new channel id and a `name` tag, optional `visibility`, `channel_type`, label `t` and `unlisted` tags. The relay refuses a 9007 without `h`. It refuses a listed channel (open, not unlisted, stream or forum) whose name another listed channel already has, ignoring case and including archived ones: `invalid: an open channel named "<name>" already exists`. |
 | **Add user (kind:9000)** | ✅ | Open: any user, subject to target's `channel_add_policy` (`owner_only`/`nobody` can block). Private: owner/admin only. Self-add bypasses agent policy but not private-channel auth. A guest cannot add anyone. A new member with no role tag gets the channel's `join_role`; a non-member adding themselves may ask for `join_role` or a lower role. One event may name up to 100 people: one `p` tag each, with an optional role as the `p` tag's third element (NIP-29), falling back to the event's `role` tag. Each person is checked and added on their own. When the event names several people, the OK message is `members: ` followed by JSON listing the non-empty `added`, `updated` (role changed), `already_member` and `rejected` (`[{"reason", "pubkeys"}]`) results. The event is refused only when it is malformed or nobody it names may be added; then one person keeps the single-add error, and several get `invalid: members: {…}`. The event and its membership changes are stored together, so an `error:` rejection stores nothing and the same event can be resent; a resent stored event returns `duplicate:` without results. Re-adding someone at their current role posts no second `member_joined` notice. |
 | **Remove user (kind:9001)** | ✅ | Self-remove allowed (with last-owner guard). Removing others: owner/admin only. |
-| **Edit group metadata (kind:9002)** | ✅ | `name`/`about`/label `t`/`visibility`/`ttl`/`archived`/`join_role`/`unlisted` tags: owner/admin. `topic`/`purpose` tags: any member except a guest. `auto_join` tag: relay owner/admin (see [Default channels](#default-channels)). Buzz applies 9002 as a partial update: an absent tag leaves that setting unchanged. |
+| **Edit group metadata (kind:9002)** | ✅ | `name`/`about`/label `t`/`visibility`/`ttl`/`archived`/`join_role`/`unlisted` tags: owner/admin. `topic`/`purpose` tags: any member except a guest. `auto_join` tag: relay owner/admin (see [Default channels](#default-channels)). A relay operator may also send a 9002 that changes only `name` on a listed channel, archived ones included, whatever its channel role, so that duplicate names can be repaired; the channel stays archived. The relay refuses a `name`, `visibility` or `unlisted` change that leaves a listed channel with a name another listed channel already has: `invalid: an open channel named "<name>" already exists`. Buzz applies 9002 as a partial update: an absent tag leaves that setting unchanged. |
 | **Admin delete event (kind:9005)** | ✅ | Event author can always delete own. Otherwise owner/admin required. Target must be in same channel. |
 | **Group deletion (kind:9008)** | ✅ | Owner only. |
 | **Leave group (kind:9022)** | ✅ | Any member. Last-owner guard prevents orphaned groups. |

crates/buzz-db/src/error.rs

@@ -25,6 +25,11 @@ pub enum DbError {
     #[error("channel not found: {0}")]
     ChannelNotFound(uuid::Uuid),
 
+    /// Another listed open channel in the community already has this name
+    /// (see `channel::ensure_listed_channel_name_unique`).
+    #[error("an open channel named \"{0}\" already exists")]
+    ChannelNameTaken(String),
+
     /// The requested member is not in the channel.
     #[error("member not found in channel {0}")]
     MemberNotFound(uuid::Uuid),

crates/buzz-db/src/runtime/tests.rs

@@ -4069,6 +4069,9 @@ async fn e_tag_any_runs_with_real_binds_on_p_join_and_count() {
 #[path = "tests/thread_window_postgres_tests.rs"]
 mod thread_window_postgres_tests;
 
+#[path = "tests/listed_channel_name_postgres_tests.rs"]
+mod listed_channel_name_postgres_tests;
+
 #[path = "tests/reader_pool_postgres_tests.rs"]
 mod reader_pool_postgres_tests;