update

Cargo.lock

@@ -1318,6 +1318,7 @@ dependencies = [
  "data-encoding",
  "hkdf",
  "hmac 0.12.1",
+ "log",
  "nostr",
  "nostr-memory",
  "nostr-sdk",

crates/community/src/lib.rs

@@ -107,8 +107,9 @@ impl CommunityRegistry {
     /// Create a community owned by the current account and begin tracking it.
     pub fn create(&mut self, metadata: CommunityMetadata, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
+        let current_user = nostr.read(cx).current_user();
 
-        if nostr.read(cx).current_user().is_none() {
+        if current_user.is_none() {
             cx.emit(CommunityEvent::Error(
                 "cannot create a community without an account".to_owned(),
             ));

crates/community/src/sync.rs

@@ -14,9 +14,6 @@ use concord::{ChannelId, CommunityId, Epoch, GroupKey};
 use nostr_sdk::prelude::*;
 use state::UniversalSigner;
 
-const SUBSCRIPTION_PREFIX: &str = "concord/";
-const STATE_PREFIX: &str = "concord/";
-
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum PlaneKind {
     Control(Epoch),
@@ -77,13 +74,13 @@ pub fn subscription_filter(planes: &[Plane]) -> Filter {
 }
 
 pub fn subscription_id(id: &CommunityId) -> SubscriptionId {
-    SubscriptionId::new(format!("{SUBSCRIPTION_PREFIX}{}", id.to_hex()))
+    SubscriptionId::new(format!("{}{}", store::STATE_PREFIX, id.to_hex()))
 }
 
 pub fn community_of(subscription_id: &SubscriptionId) -> Option<CommunityId> {
     subscription_id
         .as_str()
-        .strip_prefix(SUBSCRIPTION_PREFIX)?
+        .strip_prefix(store::STATE_PREFIX)?
         .parse()
         .ok()
 }
@@ -130,30 +127,7 @@ pub async fn load(
     signer: &UniversalSigner,
     self_pk: PublicKey,
 ) -> Result<Vec<CommunityState>> {
-    let filter = Filter::new().kind(Kind::ApplicationSpecificData);
-    let mut newest: BTreeMap<CommunityId, Event> = BTreeMap::new();
-
-    for event in client.database().query(filter).await? {
-        let Some(id) = state_document_of(&event) else {
-            continue;
-        };
-
-        match newest.get(&id) {
-            Some(existing) if existing.created_at >= event.created_at => {}
-            _ => {
-                newest.insert(id, event);
-            }
-        }
-    }
-
-    let mut states = Vec::with_capacity(newest.len());
-
-    for event in newest.into_values() {
-        match serde_json::from_str::<CommunityState>(&event.content) {
-            Ok(state) => states.push(state),
-            Err(error) => log::warn!("ignoring malformed community state {}: {error}", event.id),
-        }
-    }
+    let mut states = store::load_states(client).await?;
 
     if let Some(list) = load_list(client, signer, self_pk).await? {
         states.retain(|state| list.is_live(&state.id));
@@ -162,12 +136,6 @@ pub async fn load(
     Ok(states)
 }
 
-fn state_document_of(event: &Event) -> Option<CommunityId> {
-    let identifier = event.tags.identifier()?;
-    let hex = identifier.strip_prefix(STATE_PREFIX)?;
-    hex.parse().ok()
-}
-
 async fn load_list(
     client: &Client,
     signer: &UniversalSigner,

crates/concord/Cargo.toml

@@ -17,6 +17,7 @@ rand.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 anyhow.workspace = true
+log.workspace = true
 
 [dev-dependencies]
 nostr-memory.workspace = true

crates/concord/src/cords/cord02/guestbook.rs

@@ -1,18 +1,16 @@
 use std::cmp::Reverse;
 use std::collections::{BTreeMap, BTreeSet};
-use std::fmt;
 
 use anyhow::Result;
 use data_encoding::HEXLOWER;
 use nostr_sdk::prelude::*;
 
 use crate::cord01::{
-    KIND_WRAP, OpenedStream, SealForm, StreamError, build_rumor_ms, build_seal, open_wrap,
-    wrap_seal,
-};
-use crate::cord04::{
-    AuthorityCitation, TAG_CITATION, canonical_decimal, citation_from, citation_tag,
+    KIND_WRAP, OpenedStream, SealForm, build_rumor_ms, build_seal, open_wrap, wrap_seal,
 };
+use crate::cord04::{AuthorityCitation, canonical_decimal, citation_tag};
+pub use crate::cords::rumor::RumorError as GuestbookError;
+use crate::cords::rumor::{optional_citation, pubkey, required, value};
 use crate::{GroupKey, decode_hex_32};
 
 pub const KIND_JOIN_LEAVE: u16 = 3306;
@@ -29,41 +27,6 @@ const TAG_CONTENT: &str = "content";
 const CONTENT_JOIN: &str = "join";
 const CONTENT_LEAVE: &str = "leave";
 
-#[derive(Debug)]
-pub enum GuestbookError {
-    Stream(StreamError),
-    NotEncryptedSealed,
-    UnknownKind(u16),
-    MissingTag(&'static str),
-    DuplicateTag(&'static str),
-    BadTag(&'static str),
-}
-
-impl fmt::Display for GuestbookError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            GuestbookError::Stream(error) => write!(f, "stream: {error}"),
-            GuestbookError::NotEncryptedSealed => {
-                write!(f, "guestbook rumor must ride an encrypted seal")
-            }
-            GuestbookError::UnknownKind(kind) => {
-                write!(f, "not a guestbook rumor kind: {kind}")
-            }
-            GuestbookError::MissingTag(name) => write!(f, "missing guestbook tag: {name}"),
-            GuestbookError::DuplicateTag(name) => write!(f, "duplicate guestbook tag: {name}"),
-            GuestbookError::BadTag(name) => write!(f, "malformed guestbook tag: {name}"),
-        }
-    }
-}
-
-impl std::error::Error for GuestbookError {}
-
-impl From<StreamError> for GuestbookError {
-    fn from(error: StreamError) -> Self {
-        GuestbookError::Stream(error)
-    }
-}
-
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum GuestbookEntry {
     Join {
@@ -469,73 +432,21 @@ fn snapshot_of(rumor: &UnsignedEvent) -> Result<([u8; 32], (u32, u32)), Guestboo
     Ok((snapshot_id, (index, total)))
 }
 
-fn optional_citation(rumor: &UnsignedEvent) -> Result<Option<AuthorityCitation>, GuestbookError> {
-    let Some(fields) = tag(rumor, TAG_CITATION)? else {
-        return Ok(None);
-    };
-
-    citation_from(fields)
-        .map(Some)
-        .ok_or(GuestbookError::BadTag(TAG_CITATION))
-}
-
 fn decimal(raw: &str) -> Result<u32, GuestbookError> {
     canonical_decimal(raw)
         .and_then(|value| u32::try_from(value).ok())
         .ok_or(GuestbookError::BadTag(TAG_SNAP))
 }
 
-fn required<'a>(
-    rumor: &'a UnsignedEvent,
-    name: &'static str,
-) -> Result<&'a [String], GuestbookError> {
-    tag(rumor, name)?.ok_or(GuestbookError::MissingTag(name))
-}
-
 fn tagged_pubkey(rumor: &UnsignedEvent, name: &'static str) -> Result<PublicKey, GuestbookError> {
     pubkey(value(required(rumor, name)?, name)?, name)
 }
 
-fn tag<'a>(
-    rumor: &'a UnsignedEvent,
-    name: &'static str,
-) -> Result<Option<&'a [String]>, GuestbookError> {
-    let mut found: Option<&[String]> = None;
-
-    for candidate in rumor.tags.iter() {
-        let fields = candidate.as_slice();
-
-        if fields.first().map(String::as_str) != Some(name) {
-            continue;
-        }
-
-        if found.is_some() {
-            return Err(GuestbookError::DuplicateTag(name));
-        }
-
-        found = Some(fields);
-    }
-
-    Ok(found)
-}
-
-fn value<'a>(fields: &'a [String], name: &'static str) -> Result<&'a str, GuestbookError> {
-    fields
-        .get(1)
-        .map(String::as_str)
-        .ok_or(GuestbookError::BadTag(name))
-}
-
-fn pubkey(hex: &str, name: &'static str) -> Result<PublicKey, GuestbookError> {
-    let bytes = decode_hex_32(hex).map_err(|_| GuestbookError::BadTag(name))?;
-
-    PublicKey::from_slice(&bytes).map_err(|_| GuestbookError::BadTag(name))
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::cord01::build_rumor_secs;
+    use crate::cord01::{StreamError, build_rumor_secs};
+    use crate::cord04::TAG_CITATION;
     use crate::derive::guestbook_group_key;
     use crate::{CommunityId, Epoch};
 

crates/concord/src/cords/cord03.rs

@@ -1,18 +1,16 @@
 use std::cmp::Reverse;
 use std::collections::BTreeMap;
-use std::fmt;
 
 use anyhow::Result;
 use nostr_sdk::prelude::*;
 
 use crate::cord01::{
-    KIND_WRAP, KIND_WRAP_EPHEMERAL, OpenedStream, SealForm, StreamError, build_rumor_ms,
-    build_seal, channel_binding_tags, check_channel_binding, open_wrap, resolve_ms_strict,
-    wrap_seal,
-};
-use crate::cord04::{
-    AuthorityCitation, TAG_CITATION, canonical_decimal, citation_from, citation_tag,
+    KIND_WRAP, KIND_WRAP_EPHEMERAL, OpenedStream, SealForm, build_rumor_ms, build_seal,
+    channel_binding_tags, check_channel_binding, open_wrap, resolve_ms_strict, wrap_seal,
 };
+use crate::cord04::{AuthorityCitation, canonical_decimal, citation_tag};
+pub use crate::cords::rumor::RumorError as ChatError;
+use crate::cords::rumor::{optional_citation, pubkey, tag, value};
 use crate::derive::channel_group_key;
 use crate::{ChannelId, Epoch, GroupKey, decode_hex_32};
 
@@ -36,42 +34,6 @@ const TAG_TARGET_AUTHOR: &str = "p";
 const TAG_EXPIRATION: &str = "expiration";
 const TAG_TIMER: &str = "timer";
 
-#[derive(Debug)]
-pub enum ChatError {
-    Stream(StreamError),
-    NotEncryptedSealed,
-    UnknownKind(u16),
-    MissingTag(&'static str),
-    DuplicateTag(&'static str),
-    BadTag(&'static str),
-    /// Neither a delete nor a timer notice may be erased by the policy it carries.
-    ExemptExpiration,
-}
-
-impl fmt::Display for ChatError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            ChatError::Stream(error) => write!(f, "stream: {error}"),
-            ChatError::NotEncryptedSealed => write!(f, "chat rumor must ride an encrypted seal"),
-            ChatError::UnknownKind(kind) => write!(f, "not a chat rumor kind: {kind}"),
-            ChatError::MissingTag(name) => write!(f, "missing chat tag: {name}"),
-            ChatError::DuplicateTag(name) => write!(f, "duplicate chat tag: {name}"),
-            ChatError::BadTag(name) => write!(f, "malformed chat tag: {name}"),
-            ChatError::ExemptExpiration => {
-                write!(f, "a delete or timer notice must not carry an expiration")
-            }
-        }
-    }
-}
-
-impl std::error::Error for ChatError {}
-
-impl From<StreamError> for ChatError {
-    fn from(error: StreamError) -> Self {
-        ChatError::Stream(error)
-    }
-}
-
 /// A chat event another chat event refers to: a quote, a comment's parent, a reaction's target.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct ReplyRef {
@@ -579,16 +541,6 @@ fn optional_kind(rumor: &UnsignedEvent, name: &'static str) -> Result<Option<u16
         .map_err(|_| ChatError::BadTag(name))
 }
 
-fn optional_citation(rumor: &UnsignedEvent) -> Result<Option<AuthorityCitation>, ChatError> {
-    let Some(fields) = tag(rumor, TAG_CITATION)? else {
-        return Ok(None);
-    };
-
-    citation_from(fields)
-        .map(Some)
-        .ok_or(ChatError::BadTag(TAG_CITATION))
-}
-
 pub fn expiration_of(rumor: &UnsignedEvent) -> Result<Option<Timestamp>, ChatError> {
     let Some(fields) = tag(rumor, TAG_EXPIRATION)? else {
         return Ok(None);
@@ -614,51 +566,16 @@ fn reply_tag(name: &str, reply: &ReplyRef) -> Tag {
     )
 }
 
-fn tag<'a>(
-    rumor: &'a UnsignedEvent,
-    name: &'static str,
-) -> Result<Option<&'a [String]>, ChatError> {
-    let mut found: Option<&[String]> = None;
-
-    for candidate in rumor.tags.iter() {
-        let fields = candidate.as_slice();
-
-        if fields.first().map(String::as_str) != Some(name) {
-            continue;
-        }
-
-        if found.is_some() {
-            return Err(ChatError::DuplicateTag(name));
-        }
-
-        found = Some(fields);
-    }
-
-    Ok(found)
-}
-
-fn value<'a>(fields: &'a [String], name: &'static str) -> Result<&'a str, ChatError> {
-    fields
-        .get(1)
-        .map(String::as_str)
-        .ok_or(ChatError::BadTag(name))
-}
-
 fn hex_id(fields: &[String], name: &'static str) -> Result<EventId, ChatError> {
     let bytes = decode_hex_32(value(fields, name)?).map_err(|_| ChatError::BadTag(name))?;
 
     EventId::from_slice(&bytes).map_err(|_| ChatError::BadTag(name))
 }
 
-fn pubkey(hex: &str, name: &'static str) -> Result<PublicKey, ChatError> {
-    let bytes = decode_hex_32(hex).map_err(|_| ChatError::BadTag(name))?;
-
-    PublicKey::from_slice(&bytes).map_err(|_| ChatError::BadTag(name))
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::cord01::StreamError;
 
     const SECRET: [u8; 32] = [0x2du8; 32];
     const AT: u64 = 1_700_000_000_417;

crates/concord/src/cords/cord04/mod.rs

@@ -121,7 +121,7 @@ fn signing_bytes(
     bytes
 }
 
-pub fn edition_hash(
+fn edition_hash(
     entity: &[u8; 32],
     version: u64,
     prev: Option<&[u8; 32]>,
@@ -246,14 +246,14 @@ impl From<&ParsedEdition> for EditionMeta {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub struct FoldResult {
+struct FoldResult {
     pub head: Option<usize>,
     pub gap: bool,
     pub anchored: bool,
 }
 
 /// The highest version whose chain is intact, given a held floor.
-pub fn fold(editions: &[EditionMeta], floor: u64, floor_hash: Option<&[u8; 32]>) -> FoldResult {
+fn fold(editions: &[EditionMeta], floor: u64, floor_hash: Option<&[u8; 32]>) -> FoldResult {
     let mut by_version: BTreeMap<u64, usize> = BTreeMap::new();
 
     for (index, edition) in editions.iter().enumerate() {
@@ -311,7 +311,7 @@ pub fn fold(editions: &[EditionMeta], floor: u64, floor_hash: Option<&[u8; 32]>)
 }
 
 /// The highest version overall, ignoring contiguity.
-pub fn bootstrap_head(editions: &[EditionMeta]) -> Option<usize> {
+fn bootstrap_head(editions: &[EditionMeta]) -> Option<usize> {
     editions
         .iter()
         .enumerate()

crates/concord/src/cords/cord04/roles.rs

@@ -100,7 +100,7 @@ pub struct Role {
 }
 
 impl Role {
-    pub fn parse(content: &str) -> Option<Self> {
+    fn parse(content: &str) -> Option<Self> {
         serde_json::from_str(content).ok()
     }
 
@@ -122,7 +122,7 @@ pub struct Grant {
 }
 
 impl Grant {
-    pub fn parse(content: &str) -> Option<Self> {
+    fn parse(content: &str) -> Option<Self> {
         serde_json::from_str(content).ok()
     }
 
@@ -135,7 +135,7 @@ impl Grant {
     }
 }
 
-pub fn parse_banlist(content: &str) -> Option<Vec<PublicKey>> {
+fn parse_banlist(content: &str) -> Option<Vec<PublicKey>> {
     let entries: Vec<String> = serde_json::from_str(content).ok()?;
     let mut banned = Vec::with_capacity(entries.len());
 

crates/concord/src/cords/mod.rs

@@ -1,3 +1,5 @@
+mod rumor;
+
 pub mod cord01;
 pub mod cord02;
 pub mod cord03;

crates/concord/src/cords/rumor.rs

@@ -0,0 +1,96 @@
+use std::fmt;
+
+use nostr_sdk::prelude::*;
+
+use crate::cord01::StreamError;
+use crate::cord04::{AuthorityCitation, TAG_CITATION, citation_from};
+use crate::decode_hex_32;
+
+#[derive(Debug)]
+pub enum RumorError {
+    Stream(StreamError),
+    NotEncryptedSealed,
+    UnknownKind(u16),
+    MissingTag(&'static str),
+    DuplicateTag(&'static str),
+    BadTag(&'static str),
+    /// Neither a delete nor a timer notice may be erased by the policy it carries.
+    ExemptExpiration,
+}
+
+impl fmt::Display for RumorError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            RumorError::Stream(error) => write!(f, "stream: {error}"),
+            RumorError::NotEncryptedSealed => write!(f, "rumor must ride an encrypted seal"),
+            RumorError::UnknownKind(kind) => write!(f, "not a rumor kind: {kind}"),
+            RumorError::MissingTag(name) => write!(f, "missing tag: {name}"),
+            RumorError::DuplicateTag(name) => write!(f, "duplicate tag: {name}"),
+            RumorError::BadTag(name) => write!(f, "malformed tag: {name}"),
+            RumorError::ExemptExpiration => {
+                write!(f, "a delete or timer notice must not carry an expiration")
+            }
+        }
+    }
+}
+
+impl std::error::Error for RumorError {}
+
+impl From<StreamError> for RumorError {
+    fn from(error: StreamError) -> Self {
+        RumorError::Stream(error)
+    }
+}
+
+pub fn tag<'a>(
+    rumor: &'a UnsignedEvent,
+    name: &'static str,
+) -> Result<Option<&'a [String]>, RumorError> {
+    let mut found: Option<&[String]> = None;
+
+    for candidate in rumor.tags.iter() {
+        let fields = candidate.as_slice();
+
+        if fields.first().map(String::as_str) != Some(name) {
+            continue;
+        }
+
+        if found.is_some() {
+            return Err(RumorError::DuplicateTag(name));
+        }
+
+        found = Some(fields);
+    }
+
+    Ok(found)
+}
+
+pub fn required<'a>(
+    rumor: &'a UnsignedEvent,
+    name: &'static str,
+) -> Result<&'a [String], RumorError> {
+    tag(rumor, name)?.ok_or(RumorError::MissingTag(name))
+}
+
+pub fn value<'a>(fields: &'a [String], name: &'static str) -> Result<&'a str, RumorError> {
+    fields
+        .get(1)
+        .map(String::as_str)
+        .ok_or(RumorError::BadTag(name))
+}
+
+pub fn pubkey(hex: &str, name: &'static str) -> Result<PublicKey, RumorError> {
+    let bytes = decode_hex_32(hex).map_err(|_| RumorError::BadTag(name))?;
+
+    PublicKey::from_slice(&bytes).map_err(|_| RumorError::BadTag(name))
+}
+
+pub fn optional_citation(rumor: &UnsignedEvent) -> Result<Option<AuthorityCitation>, RumorError> {
+    let Some(fields) = tag(rumor, TAG_CITATION)? else {
+        return Ok(None);
+    };
+
+    citation_from(fields)
+        .map(Some)
+        .ok_or(RumorError::BadTag(TAG_CITATION))
+}

crates/concord/src/store.rs

@@ -23,7 +23,8 @@ const MARK_TAG: SingleLetterTag = SingleLetterTag::LOWERCASE_T;
 const MARK_VALUE: &str = "concord";
 const WRAP_TAG: &str = "e";
 const KIND_TAG: &str = "k";
-const STATE_PREFIX: &str = "concord/";
+/// The `concord/` namespace for locally-keyed documents.
+pub const STATE_PREFIX: &str = "concord/";
 
 /// An already-expired rumor is refused at ingest. Returns whether it was kept.
 pub async fn cache_rumor(
@@ -91,7 +92,7 @@ pub async fn purge_expired(client: &Client, channel: &ChannelId, now: Timestamp)
 }
 
 pub async fn query_rumors(
-    database: &dyn NostrDatabase,
+    client: &Client,
     channel: &ChannelId,
     until: Option<Timestamp>,
     limit: usize,
@@ -106,7 +107,7 @@ pub async fn query_rumors(
     }
 
     let mut newest: BTreeMap<String, Event> = BTreeMap::new();
-    for event in database.query(filter).await? {
+    for event in client.database().query(filter).await? {
         let Some(rumor_id) = event.tags.identifier() else {
             continue;
         };
@@ -297,21 +298,54 @@ pub async fn save_state(client: &Client, state: &CommunityState) -> Result<()> {
     Ok(())
 }
 
-pub async fn load_state<D>(database: &D, id: &CommunityId) -> Result<Option<CommunityState>>
-where
-    D: NostrDatabase + ?Sized,
-{
+pub async fn load_state(client: &Client, id: &CommunityId) -> Result<Option<CommunityState>> {
     let filter = Filter::new()
         .kind(Kind::ApplicationSpecificData)
         .identifier(state_identifier(id))
         .limit(1);
 
-    match database.query(filter).await?.into_iter().next() {
+    match client.database().query(filter).await?.into_iter().next() {
         Some(event) => Ok(Some(serde_json::from_str(&event.content)?)),
         None => Ok(None),
     }
 }
 
+/// The newest state document per community carried in the local database.
+pub async fn load_states(client: &Client) -> Result<Vec<CommunityState>> {
+    let filter = Filter::new().kind(Kind::ApplicationSpecificData);
+    let mut newest: BTreeMap<CommunityId, Event> = BTreeMap::new();
+
+    for event in client.database().query(filter).await? {
+        let Some(id) = state_document_of(&event) else {
+            continue;
+        };
+
+        match newest.get(&id) {
+            Some(existing) if existing.created_at >= event.created_at => {}
+            _ => {
+                newest.insert(id, event);
+            }
+        }
+    }
+
+    let mut states = Vec::with_capacity(newest.len());
+
+    for event in newest.into_values() {
+        match serde_json::from_str::<CommunityState>(&event.content) {
+            Ok(state) => states.push(state),
+            Err(error) => log::warn!("ignoring malformed community state {}: {error}", event.id),
+        }
+    }
+
+    Ok(states)
+}
+
+fn state_document_of(event: &Event) -> Option<CommunityId> {
+    let identifier = event.tags.identifier()?;
+    let hex = identifier.strip_prefix(STATE_PREFIX)?;
+    hex.parse().ok()
+}
+
 pub async fn backfill(
     client: &Client,
     channel: &ChannelId,
@@ -492,4 +526,43 @@ mod tests {
             ["after the rekey", "still before", "before the rekey"]
         );
     }
+
+    #[test]
+    fn load_states_reads_one_document_per_community_and_ignores_other_documents() {
+        smol::block_on(async {
+            let client = ClientBuilder::default()
+                .database(nostr_memory::MemoryDatabase::unbounded())
+                .build();
+
+            let state = CommunityState {
+                id: CommunityId::from_bytes([0x42; 32]),
+                owner: Keys::generate().public_key(),
+                owner_salt: [0x01; 32],
+                community_root: [0x02; 32],
+                root_epoch: Epoch(0),
+                control_root: None,
+                control_pks: BTreeMap::new(),
+                channels: Vec::new(),
+                relays: Vec::new(),
+                heads: Vec::new(),
+                banned: BTreeSet::new(),
+                dissolved: false,
+                added_at_ms: 7,
+            };
+
+            save_state(&client, &state).await.expect("saves");
+
+            // A cached rumor is also an application-specific document, but not a
+            // state document, so the prefix keeps it out of the state scan.
+            let other = EventBuilder::new(Kind::ApplicationSpecificData, "{}")
+                .tags([Tag::identifier("deadbeef")])
+                .finalize(&*LOCAL_KEYS)
+                .expect("builds");
+            client.database().save_event(&other).await.expect("saves");
+
+            let loaded = load_states(&client).await.expect("loads");
+
+            assert_eq!(loaded, vec![state]);
+        });
+    }
 }

crates/workspace/src/sidebar/tree.rs

@@ -80,7 +80,7 @@ pub struct CommunityEntry {
 }
 
 pub fn dummy_communities() -> &'static [CommunityEntry] {
-    // TODO(concord): replace with ConcordRegistry communities, see docs/concord-usage.md.
+    // TODO(concord): replace with CommunityRegistry communities, see docs/concord-usage.md.
     &[
         CommunityEntry {
             name: "Coop Contributors",

docs/concord-simplification-plan.md

@@ -251,25 +251,36 @@ Validation: `cargo test -p concord` — 46 passed, 0 failed (the 80-blob
 the base64 record). `cargo clippy -p concord --all-targets` and
 `cargo fmt -p concord --check` are clean.
 
-### Phase 4 — duplication and hygiene (independent, low risk)
+### Phase 4 — duplication and hygiene (independent, low risk) — DONE
 
-1. Add `store::load_states(client)` and delete the app-side state-document scan
-   (`crates/community/src/sync.rs:100-137`).
-2. Export the `concord/` state prefix from concord; delete the app-side copies
-   (`store.rs:26`, `sync.rs:15-16`).
-3. Collapse the duplicated tag parsers (`cord03.rs:614-654` vs
-   `guestbook.rs:496-530`) and the identical `ChatError`/`GuestbookError`
-   enums.
-4. Remove never-varied parameters where the change is local: `banned_at` from
-   `complete_memberlist` (doc admits "empty today"), `cache_rumor -> Result<()>`
-   once nothing reads the bool, `snapshot_authority`/`ephemeral`/`query_rumors
-   (until)` if no scheduled flow needs them.
-5. Tighten visibility of internal-only `pub` items in `cord04`
-   (`edition_hash`, `fold`, `FoldResult`, `bootstrap_head`, `HeadSelection`,
-   `parse_banlist`, `Role::parse`, `Grant::parse`).
-6. Fix doc drift: `backfill` arity (`docs/concord-usage.md:212`), `save_state`
-   parameter (`:487`), `init` signature (`:431-432`), and refresh the "Not wired
-   up yet" section (`:528-545`) once Phase 2 lands.
+1. DONE — `store::load_states(client)` added (with a direct `store` test), the
+   app-side state-document scan in `sync::load` is gone.
+2. DONE — `store::STATE_PREFIX` is public; the app-side `concord/` literals are
+   gone, and subscription ids reuse the exported prefix.
+3. DONE — the shared rumor tag readers and error live in a new `cords::rumor`
+   module (`RumorError`, `tag`, `required`, `value`, `pubkey`,
+   `optional_citation`), re-exported as `cord03::ChatError` and
+   `cord02::guestbook::GuestbookError`. `cord06` keeps its own narrower
+   `RekeyError`, which the plan scoped out.
+4. RETAINED — none of the "never-varied parameters" were removed. Each is
+   load-bearing for a flow the fold or a writer already implements (D1):
+   - `complete_memberlist`'s `banned_at` is read by the fold and is exercised
+     with a non-empty map by `join_leave_kick_and_snapshot_converge_to_one_memberlist`;
+     `docs/concord-usage.md` already promises to fill it once the banlist head's
+     timestamp is plumbed through.
+   - `cache_rumor -> Result<bool>` is read by `backfill` to drop expired rumors.
+   - `coalesce`'s `snapshot_authority` gates which snapshots apply; passing
+     `None` today is a policy, not a dead parameter.
+   - `seal_rumor(ephemeral)` and the `until` cursors on `backfill`/`query_rumors`
+     select protocol modes and paging.
+5. DONE — tightened `cord04` visibility: `edition_hash`, `fold`, `FoldResult`,
+   `bootstrap_head`, `parse_banlist`, `Role::parse` and `Grant::parse` are no
+   longer `pub`. `HeadSelection` stays `pub` because the public `fold_head`
+   returns it.
+6. DONE — doc drift fixed: the store takes `&Client` throughout (including
+   `load_state`/`load_states`/`query_rumors`, not just the writers), `backfill`
+   arity, `set_pin_list`'s missing `.await`, the GPUI `init` signature and
+   registry names, and the "Not wired up yet" registry bullet.
 
 ---
 
@@ -284,7 +295,7 @@ Per D1 these stay, but they should be understood as unwired, not live:
 | `cord04::pins` | ~550 | none |
 | `cord03` write path + `fold` + `plane_keys` | ~340 | only `open` / `expiration_of` |
 | guestbook / list write paths | ~240 | `open`, `coalesce`, `complete_memberlist`, `is_live` |
-| `store` paging / purge / query / load_state | ~180 | `cache_rumor`, `save_state` |
+| `store` paging / purge / query / load_state(s) | ~180 | `cache_rumor`, `save_state`, `load_states` |
 
 Truly unreferenced even by tests (safe candidates, but kept per D1):
 `CommunityInvite::expired`, `GroupKey::pk_hex`, `From<[u8; 32]>` impls,
@@ -310,6 +321,9 @@ Truly unreferenced even by tests (safe candidates, but kept per D1):
 - Phase 2 adds the app-level test: seed a `CommunityState` via
   `store::save_state`, drive `CommunityRegistry`, assert a subscription is made
   and an inbound wrap folds into the community.
+- Phase 4: `cargo test -p concord -p community` (47 + 1 passed),
+  `cargo clippy -p concord -p community --all-targets`, and
+  `cargo fmt -p concord -p community --check` are all clean.
 
 ## 6. Immediate unblock
 

docs/concord-usage.md

@@ -73,7 +73,7 @@ let editions: Vec<ParsedEdition> = minted
     .collect::<Result<_, _>>()?;
 
 let mut state = CommunityState::from_genesis(&minted, &editions, added_at_ms)?;
-save_state(database, &state).await?;
+save_state(&client, &state).await?;
 ```
 
 Put the community's relay list into `state.relays` and add those relays to the
@@ -192,7 +192,7 @@ for wrap in &wraps {
     let Ok((opened, rumor)) = cord03::open(wrap, group, &channel, *epoch) else {
         continue;
     };
-    store::cache_rumor(database, &channel, &opened).await?;
+    store::cache_rumor(&client, &channel, &opened).await?;
     rumors.push(rumor);
 }
 
@@ -209,13 +209,13 @@ let messages = fold(&rumors, Timestamp::now(), |actor, citation, author| {
 Relay history pages through the local cache:
 
 ```rust
-let page = store::backfill(client, database, &channel, &held, until, 50).await?;
-let cached = store::query_rumors(database, &channel, None, 50).await?;
+let page = store::backfill(client, &channel, &held, until, 50).await?;
+let cached = store::query_rumors(&client, &channel, None, 50).await?;
 ```
 
 `backfill` walks newest-first across every held epoch, caches what it opens, and
 stops on a short page. `query_rumors` is the read path when the group keys are
-gone. Run `store::purge_expired(database, &channel, now)` on the same cadence as
+gone. Run `store::purge_expired(client, &channel, now)` on the same cadence as
 any other local sweep — the timer is cooperative, so the local store is the
 artifact that has to forget.
 
@@ -275,7 +275,7 @@ let head_content = control.pin_content(&community_id, &channel).unwrap_or("");
 let read = cord04::pins::read_list(head_content, |epoch| channel_group_key(&root, &channel, epoch).ok());
 let content = cord04::pins::publishable(&read, channel_is_private, &plane, epoch)?;
 let (wrap, _) = writer.set_pin_list(
-    &my_keys, &community_id, &channel, &content, head, citation, now_secs)?;
+    &my_keys, &community_id, &channel, &content, head, citation, now_secs).await?;
 ```
 
 Reading is verification: `read_list` decodes either content form (public, or
@@ -428,7 +428,8 @@ the NIP-44 size cap, both protocol constants.
 
 ## GPUI integration
 
-`crates/concord` stays GPUI-free. The UI layer adds a registry global and one
+`crates/concord` stays GPUI-free; the registry and sync engine live in
+`crates/community`. That layer adds a registry global and one
 entity per community, and moves every decrypt, verification, fold and I/O off
 the foreground thread.
 
@@ -437,13 +438,13 @@ the foreground thread.
 Same shape as `ChatRegistry`:
 
 ```rust
-pub fn init(window: &mut Window, cx: &mut App) {
-    ConcordRegistry::set_global(cx.new(|cx| ConcordRegistry::new(window, cx)), cx);
+pub fn init(cx: &mut App) {
+    CommunityRegistry::set_global(cx.new(CommunityRegistry::new), cx);
 }
 
-impl ConcordRegistry {
+impl CommunityRegistry {
     pub fn global(cx: &App) -> Entity<Self> {
-        cx.global::<GlobalConcordRegistry>().0.clone()
+        cx.global::<GlobalCommunityRegistry>().0.clone()
     }
 }
 ```
@@ -452,8 +453,8 @@ Call it after `cord03::init` in `desktop/src/main.rs` and `web/src/lib.rs`, and
 subscribe to `NostrRegistry` for `SignerChanged` so the communities reset with
 the account.
 
-- `ConcordRegistry` holds `communities: Vec<Entity<Community>>`, an index by
-  `CommunityId`, and `tasks: SmallVec<[Task<Result<(), Error>>; 2]>`.
+- `CommunityRegistry` holds `communities: Vec<Entity<Community>>`, an index by
+  `CommunityId`, and `tasks: SmallVec<[Task<Result<()>>; 2]>`.
 - `Community` owns one `CommunityState`, the last `ControlFold`, the member list
   and the channel list. Views render `Entity<Community>`; no protocol state
   lives in a view.
@@ -468,7 +469,7 @@ A background task never touches an entity. It sends results through a bounded
 
 ```rust
 let (signal_tx, signal_rx) = flume::bounded::<Signal>(256);
-let database = client.database().clone();
+let client = client.clone();
 
 // Background: open, verify, fold — no entities.
 self.ingress = Some(cx.background_spawn(async move {
@@ -477,7 +478,7 @@ self.ingress = Some(cx.background_spawn(async move {
             continue;
         };
         let (opened, rumor) = cord03::open(wrap, &plane.group, &plane.channel, plane.epoch)?;
-        store::cache_rumor(database.as_ref(), &plane.channel, &opened).await?;
+        store::cache_rumor(&client, &plane.channel, &opened).await?;
         signal_tx.send_async(Signal::Chat { channel: plane.channel, rumor }).await?;
     }
     Ok(())
@@ -492,8 +493,8 @@ self.consumer = Some(cx.spawn(async move |this, cx| {
 }));
 ```
 
-- `client.database()` is a `&Arc<dyn NostrDatabase>` and `store::save_state`
-  wants `&dyn NostrDatabase`, so clone the `Arc` and pass `database.as_ref()`.
+- Every store function takes the `&Client` and reaches the database through
+  `client.database()`, so clone the `Client` into the background task.
 - Keep long-lived tasks in fields — dropping a `Task` cancels it. Assign `None`
   to an `Option<Task<_>>` before respawning it; a signer change replaces both
   the listener and the consumer.
@@ -537,11 +538,13 @@ client.subscribe(filter).with_id(sub_id).await?;
 
 ## Not wired up yet
 
-- **No registry and no sync engine.** `crates/concord` has no subscriptions, no
-  `init`, and no `Entity<Community>`; the UI owns subscribing, routing a wrap to
-  the plane whose address it carries, and rebuilding a subscription when a plane's
-  address changes (join, channel added, rekey folded). GPUI integration above is
-  the shape to build, not code that exists.
+- **`crates/concord` stays protocol-only; the registry lives in
+  `crates/community`.** `concord` has no subscriptions, no `init`, and no
+  `Entity<Community>`; `community::CommunityRegistry` owns one `Entity<Community>`
+  per state document, subscribes when a community's plane set changes, and
+  re-folds on an inbound wrap. Nothing observes `CommunityEvent` yet, and
+  `CommunityRegistry::create` persists the genesis locally without publishing it
+  to the metadata's relays.
 - **Account-key writers take any signer, not `&Keys`.** `genesis`,
   `ControlWriter`, the guestbook and chat `seal_rumor`s, the `list` builders, and
   the `cord05` invite writers (`build_direct_invite` / `unwrap_direct_invite`,