feat: add local repository scanning (#8)

Reviewed-on: https://git.reya.su/reya/signed/pulls/8

crates/signed_state/src/backend.rs

@@ -1,4 +1,5 @@
 use std::collections::HashMap;
+use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::time::Duration;
 
@@ -9,7 +10,7 @@ use nostr::event::IntoEventBuilder;
 use nostr_connect::prelude::*;
 use nostr_sdk::client::SyncSummary;
 use nostr_sdk::prelude::*;
-use signed_core::{Announcement, build_state, filters, repo_addr};
+use signed_core::{Announcement, RepoAddr, build_state, filters, identifier_from_name, repo_addr};
 use signed_nostr::{SignedAuthUrlHandler, UniversalSigner, Update};
 
 use crate::git_store::GitStore;
@@ -496,15 +497,30 @@ impl Backend {
                 })?
                 .await?;
 
-            this.update(cx, |this, cx| {
-                let builder = build_state(
-                    &repo_id,
-                    &[("refs/heads/main".to_owned(), commit)],
-                    Some("main"),
-                );
-                this.send(builder, cx)
-            })?
-            .await?;
+            let state_event = match this
+                .update(cx, |this, cx| {
+                    let builder = build_state(
+                        &repo_id,
+                        &[("refs/heads/main".to_owned(), commit)],
+                        Some("main"),
+                    );
+                    this.send(builder, cx)
+                })?
+                .await
+            {
+                Ok(state_event) => state_event,
+                Err(e) => {
+                    this.update(cx, |this, cx| {
+                        this.retract_events(std::slice::from_ref(&event), cx);
+                    })
+                    .ok();
+
+                    return Err(e.context(
+                        "The repository was announced, but its state could not be published. \
+                         The announcement has been retracted",
+                    ));
+                }
+            };
 
             // 4. Push the initial commit to every grasp server. A server
             //    that fails to accept the push is logged, but the creation
@@ -514,38 +530,285 @@ impl Backend {
                 let owner = owner.clone();
                 let repo_id = repo_id.clone();
                 let servers = servers.clone();
+                push_to_grasp_servers(path, owner, repo_id, servers, signed_git::push_main)
+            });
+            if let Err(e) = push.await {
+                // The events are already published; retract them so the
+                // repository doesn't remain announced without content.
+                this.update(cx, |this, cx| {
+                    this.retract_events(&[event.clone(), state_event.clone()], cx);
+                })
+                .ok();
 
+                return Err(e.context(
+                    "The repository was announced, but the push to every grasp server failed. \
+                     The announcement has been retracted",
+                ));
+            }
+
+            Announcement::from_event(&event).ok_or_else(|| anyhow!("failed to parse announcement"))
+        })
+    }
+
+    /// Publish an existing local repository to NIP-34: read its current
+    /// branches, tags and HEAD, publish the announcement and the repository
+    /// state to the grasp relays, then push every branch and tag to each
+    /// grasp server. Also points `origin` at the first grasp server.
+    ///
+    /// The events must reach the grasp servers *before* the push, like
+    /// [`Self::create_repository`]: GRASP servers hold the signed state
+    /// event in "purgatory" and only accept a push while that
+    /// authorization is pending.
+    ///
+    /// The git work (ref listing, push) runs on background threads. The
+    /// returned task yields the published announcement on success, so
+    /// callers can switch the repository into its NIP-34 mode.
+    pub fn publish_local_repo(
+        &mut self,
+        path: PathBuf,
+        name: &str,
+        description: &str,
+        grasp_servers: Vec<RelayUrl>,
+        cx: &mut Context<Self>,
+    ) -> Task<Result<Announcement, Error>> {
+        let name = name.trim().to_owned();
+        let description = description.trim().to_owned();
+
+        if name.is_empty() {
+            return Task::ready(Err(anyhow!("Repository name is required")));
+        }
+
+        if grasp_servers.is_empty() {
+            return Task::ready(Err(anyhow!("Add at least one grasp server")));
+        }
+
+        let Some(public_key) = self.current_user else {
+            return Task::ready(Err(anyhow!("Sign in to publish a repository")));
+        };
+
+        // The repository identifier is derived from the name, like
+        // [`Self::create_repository`]: spaces become hyphens, other
+        // non-alphanumeric characters (except `/`) become hyphens.
+        let repo_id = identifier_from_name(&name);
+
+        if repo_id.is_empty() || repo_id.len() > 100 {
+            return Task::ready(Err(anyhow!(
+                "Repository name must produce an identifier of 1-100 characters"
+            )));
+        }
+
+        if !repo_id.chars().any(|c| c.is_ascii_alphanumeric()) {
+            return Task::ready(Err(anyhow!(
+                "Repository name must contain at least one alphanumeric character"
+            )));
+        }
+
+        let owner = public_key.to_bech32().unwrap();
+        let servers = grasp_servers.clone();
+
+        cx.spawn(async move |this, cx| {
+            // 1. Read the local repository's refs (branches, tags, HEAD)
+            //    and its root commit on a background thread.
+            let work = cx.background_spawn({
+                let path = path.clone();
                 async move {
-                    let mut failures = Vec::new();
-                    let mut pushed = 0;
-                    for relay in &servers {
-                        let Some(base_url) = grasp_base_url(relay) else {
-                            failures.push(format!("{relay}: no domain"));
-                            continue;
-                        };
-                        match signed_git::push_main(&path, &base_url, &owner, &repo_id) {
-                            Ok(()) => pushed += 1,
-                            Err(e) => failures.push(format!("{relay}: {e}")),
-                        }
-                    }
-
-                    if pushed == 0 {
-                        bail!(
-                            "could not push the repository to any grasp server: {}",
-                            failures.join("; ")
-                        );
-                    }
-                    for failure in failures {
-                        log::warn!("grasp push failed: {failure}");
-                    }
-
-                    Ok::<_, Error>(())
+                    let state = signed_git::worktree_ref_state(&path)?;
+                    let euc = signed_git::root_commit(&path)?;
+                    Ok::<_, Error>((state, euc))
                 }
             });
-            push.await?;
+            let (state, euc) = work.await?;
 
-            Announcement::from_event(&event)
-                .ok_or_else(|| anyhow!("failed to parse the published announcement"))
+            // 2. Ensure the grasp servers are in the relay pool; the nostr
+            //    client queues events until each relay is connected.
+            this.update(cx, |this, cx| {
+                let urls: Vec<String> = servers.iter().map(ToString::to_string).collect();
+                this.add_relays(urls, cx);
+            })?;
+
+            // 3. Publish the announcement, then the state event, to the
+            //    grasp relays. The state event is the push authorization
+            //    ("purgatory"), so it must be accepted before step 4.
+            let announcement = GitRepositoryAnnouncement {
+                id: repo_id.clone(),
+                name: Some(name.clone()),
+                description: (!description.is_empty()).then_some(description.clone()),
+                web: Vec::new(),
+                clone: servers
+                    .iter()
+                    .filter_map(|relay| grasp_clone_url(relay, &owner, &repo_id))
+                    .collect(),
+                relays: servers.clone(),
+                euc: euc.and_then(|commit| Sha1Hash::from_str(&commit).ok()),
+                maintainers: Vec::new(),
+            };
+
+            let event = this
+                .update(cx, |this, cx| {
+                    this.send(announcement.into_event_builder(), cx)
+                })?
+                .await?;
+
+            let refs = state.refs.clone();
+            let head = state.head.clone();
+            let state_event = match this
+                .update(cx, |this, cx| {
+                    let builder = build_state(&repo_id, &refs, head.as_deref());
+                    this.send(builder, cx)
+                })?
+                .await
+            {
+                Ok(state_event) => state_event,
+                Err(e) => {
+                    this.update(cx, |this, cx| {
+                        this.retract_events(std::slice::from_ref(&event), cx);
+                    })
+                    .ok();
+
+                    return Err(e.context(
+                        "The repository was announced, but its state could not be published. \
+                         The announcement has been retracted",
+                    ));
+                }
+            };
+
+            // 4. Push every branch and tag to each grasp server. A server
+            //    that fails to accept the push is logged, but the init only
+            //    fails when no server accepted it. An empty repository
+            //    (no refs yet) has nothing to push.
+            if !refs.is_empty() {
+                let push = cx.background_spawn({
+                    let path = path.clone();
+                    let owner = owner.clone();
+                    let repo_id = repo_id.clone();
+                    let servers = servers.clone();
+                    push_to_grasp_servers(path, owner, repo_id, servers, signed_git::push_all)
+                });
+                if let Err(e) = push.await {
+                    this.update(cx, |this, cx| {
+                        this.retract_events(&[event.clone(), state_event.clone()], cx);
+                    })
+                    .ok();
+
+                    return Err(e.context(
+                        "The repository was announced, but the push to every grasp server failed. \
+                         The announcement has been retracted",
+                    ));
+                }
+            }
+
+            // 5. Point `origin` at the first grasp server so later pushes
+            //    have a target, like the create flow.
+            if let Some(base) = servers.first().and_then(grasp_base_url) {
+                let url = format!("{base}/{owner}/{repo_id}.git");
+                let path = path.clone();
+                cx.background_spawn(async move {
+                    signed_git::ensure_origin(&path, &url).ok();
+                })
+                .await;
+            }
+
+            Announcement::from_event(&event).ok_or_else(|| anyhow!("failed to parse announcement"))
+        })
+    }
+
+    /// Re-push the repository's current refs to the grasp servers announced
+    /// in its `relays` tag: publishes a fresh state event (the push
+    /// authorization), then pushes every branch and tag, like the init
+    /// flow. The repository must have a local clone in the cache.
+    pub fn push_repository(
+        &mut self,
+        announcement: Announcement,
+        cx: &mut Context<Self>,
+    ) -> Task<Result<(), Error>> {
+        let addr = announcement.addr();
+        let cache = GitStore::global(cx).cache().clone();
+        let path = cache.repo_path(&addr);
+        let owner = announcement
+            .owner
+            .to_bech32()
+            .unwrap_or_else(|_| announcement.owner.to_hex());
+        let repo_id = announcement.id.clone();
+        let relays = announcement.relays.clone();
+
+        cx.spawn(async move |this, cx| {
+            // 1. Read the current refs of the local clone.
+            let work = cx.background_spawn({
+                let path = path.clone();
+                async move { signed_git::worktree_ref_state(&path) }
+            });
+            let state = work.await?;
+
+            // 2. Publish a fresh state event; grasp servers authorize a
+            //    push by the state they have seen.
+            let refs = state.refs.clone();
+            let head = state.head.clone();
+            this.update(cx, |this, cx| {
+                let builder = build_state(&repo_id, &refs, head.as_deref());
+                this.send(builder, cx)
+            })?
+            .await?;
+
+            // 3. Push every branch and tag to the announced grasp servers.
+            if !refs.is_empty() {
+                let push = cx.background_spawn({
+                    let path = path.clone();
+                    let owner = owner.clone();
+                    let repo_id = repo_id.clone();
+                    let relays = relays.clone();
+                    async move {
+                        push_to_grasp_servers(path, owner, repo_id, relays, signed_git::push_all)
+                            .await
+                    }
+                });
+                push.await?;
+            }
+
+            Ok(())
+        })
+    }
+
+    /// Delete the repository from nostr: publish NIP-09 deletions for its
+    /// announcement, state and activity events (issues, pull requests,
+    /// patches, statuses, comments). Only the repository owner may delete
+    /// it.
+    pub fn delete_repository(
+        &mut self,
+        addr: RepoAddr,
+        cx: &mut Context<Self>,
+    ) -> Task<Result<(), Error>> {
+        let Some(public_key) = self.current_user else {
+            return Task::ready(Err(anyhow!("Sign in to delete a repository")));
+        };
+        if public_key != addr.public_key {
+            return Task::ready(Err(anyhow!("Only the repository owner can delete it")));
+        }
+
+        let client = self.client.clone();
+        let addr = addr.clone();
+
+        cx.spawn(async move |this, cx| {
+            // Collect every event of the repository from the local database.
+            let events = cx.background_spawn(async move {
+                let db = client.database();
+                let mut events = Vec::new();
+                for filter in [
+                    filters::announcement(&addr),
+                    filters::state(&addr),
+                    filters::activity(&addr),
+                ] {
+                    events.extend(db.query(filter).await?);
+                }
+                Ok::<_, Error>(events)
+            });
+            let events = events.await?;
+
+            this.update(cx, |this, cx| {
+                this.retract_events(&events, cx);
+            })
+            .ok();
+
+            Ok(())
         })
     }
 
@@ -578,9 +841,7 @@ impl Backend {
     /// Login with an `nsec1...` secret key. The credential is verified by
     /// the signer flow and persisted in the keyring.
     pub fn login_with_nsec(&mut self, nsec: &str, cx: &mut Context<Self>) {
-        let nsec = nsec.trim().to_owned();
-
-        let keys = match SecretKey::parse(&nsec) {
+        let keys = match SecretKey::parse(nsec) {
             Ok(secret) => Keys::new(secret),
             Err(e) => {
                 cx.emit(BackendEvent::error(e.to_string()));
@@ -588,15 +849,15 @@ impl Backend {
             }
         };
 
-        let write =
-            cx.write_credentials(USER_KEYRING, &keys.public_key().to_hex(), nsec.as_bytes());
+        let nsec = nsec.trim().to_owned();
+        let pubkey = keys.public_key().to_hex();
+        let write = cx.write_credentials(USER_KEYRING, &pubkey, nsec.as_bytes());
 
         self.tasks.push(cx.spawn(async move |this, cx| {
             if let Err(e) = write.await {
                 this.update(cx, |_, cx| cx.emit(BackendEvent::error(e.to_string())))?;
                 return Ok(());
             }
-
             this.update(cx, |this, cx| this.set_signer(keys, cx))?;
             Ok(())
         }));
@@ -1040,6 +1301,32 @@ impl Backend {
             Ok(())
         }));
     }
+
+    /// Publish a NIP-09 deletion event for `events` (best-effort), so a
+    /// publish that fails midway can retract the events that were already
+    /// broadcast to relays. Failures are logged, not surfaced: the caller's
+    /// error already told the user what happened.
+    fn retract_events(&mut self, events: &[Event], cx: &mut Context<Self>) {
+        if events.is_empty() {
+            return;
+        }
+
+        let mut tags: Vec<Tag> = Vec::with_capacity(events.len() * 2);
+
+        for event in events {
+            tags.push(Tag::event(event.id));
+            tags.push(Tag::parse(["k", &event.kind.to_string()]).expect("valid kind tag"));
+        }
+
+        let task = self.send(EventBuilder::new(Kind::EventDeletion, "").tags(tags), cx);
+
+        self.tasks.push(cx.spawn(async move |_this, _cx| {
+            if let Err(e) = task.await {
+                log::warn!("failed to retract repository events: {e}");
+            }
+            Ok(())
+        }));
+    }
 }
 
 /// Add the given relays, connect to them, and fetch the filters: a one-shot
@@ -1128,21 +1415,6 @@ fn with_master_key(uri: &str, keys: &Keys) -> String {
     format!("{uri}{separator}master={nsec}")
 }
 
-/// Derive a repository identifier (d-tag) from the repo name, matching ngit
-/// and gitworkshop: spaces become hyphens, other non-alphanumeric characters
-/// (except `/`) become hyphens, case is preserved.
-fn identifier_from_name(name: &str) -> String {
-    name.chars()
-        .map(|c| {
-            if c.is_ascii_alphanumeric() || c == '/' {
-                c
-            } else {
-                '-'
-            }
-        })
-        .collect()
-}
-
 /// A `https://<host>` (or `http://<host>` for `ws://` grasp servers, like
 /// ngit) base URL for a grasp server. The repository then lives at
 /// `{base}/{npub}/{repo-id}.git`.
@@ -1169,6 +1441,46 @@ fn grasp_clone_url(relay: &RelayUrl, owner: &str, repo_id: &str) -> Option<Url>
     Url::parse(&format!("{base}/{owner}/{repo_id}.git")).ok()
 }
 
+/// Push the repository at `path` to every grasp server: a server that
+/// rejects the push is logged, but the push only fails when no server
+/// accepted it. `push` performs the single-server push (e.g.
+/// [`signed_git::push_main`] for the create flow, [`signed_git::push_all`]
+/// for the init flow).
+async fn push_to_grasp_servers(
+    path: PathBuf,
+    owner: String,
+    repo_id: String,
+    servers: Vec<RelayUrl>,
+    push: fn(&Path, &str, &str, &str) -> Result<(), Error>,
+) -> Result<(), Error> {
+    let mut failures = Vec::new();
+    let mut pushed = 0;
+
+    for relay in &servers {
+        let Some(base_url) = grasp_base_url(relay) else {
+            failures.push(format!("{relay}: no domain"));
+            continue;
+        };
+        match push(&path, &base_url, &owner, &repo_id) {
+            Ok(()) => pushed += 1,
+            Err(e) => failures.push(format!("{relay}: {e}")),
+        }
+    }
+
+    if pushed == 0 {
+        bail!(
+            "could not push the repository to any grasp server: {}",
+            failures.join("; ")
+        );
+    }
+
+    for failure in failures {
+        log::warn!("grasp push failed: {failure}");
+    }
+
+    Ok(())
+}
+
 /// Split a stored bunker credential into the plain URI and the session key.
 /// Credentials without an embedded key (legacy) get a fresh one.
 fn extract_master_key(credential: &str) -> (&str, Keys) {
@@ -1187,15 +1499,6 @@ fn extract_master_key(credential: &str) -> (&str, Keys) {
 mod tests {
     use super::*;
 
-    #[test]
-    fn identifier_from_name_slugs_like_gitworkshop() {
-        assert_eq!(identifier_from_name("My Repo"), "My-Repo");
-        assert_eq!(identifier_from_name("my-repo"), "my-repo");
-        assert_eq!(identifier_from_name("Foo_Bar!"), "Foo-Bar-");
-        assert_eq!(identifier_from_name("a/b"), "a/b");
-        assert_eq!(identifier_from_name("Café"), "Caf-");
-    }
-
     #[test]
     fn grasp_base_url_maps_schemes_like_ngit() {
         let wss = RelayUrl::parse("wss://relay.ngit.dev").expect("url");

crates/signed_state/src/lib.rs

@@ -1,5 +1,6 @@
 mod backend;
 mod git_store;
+mod local_repos;
 mod profile;
 mod repo;
 mod repo_list;
@@ -9,6 +10,7 @@ use std::path::{Path, PathBuf};
 pub use backend::{Backend, BackendEvent};
 pub use git_store::GitStore;
 use gpui::{App, AppContext, Entity};
+pub use local_repos::LocalReposStore;
 pub use nostr_sdk::prelude::Timestamp;
 pub use profile::{Profile, ProfileStore};
 pub use repo::RepoStore;
@@ -16,8 +18,15 @@ pub use repo_list::{RepoActivityCounts, RepoListStore};
 use signed_nostr::new_backend;
 pub use utils::shorten_pubkey;
 
-/// Initialize the backend and stores, and install them as globals. Call once
-/// at startup, before opening any window that uses the stores.
+/// The default directories scanned for local git repositories
+/// on every platform: the user's Desktop and Documents folders.
+#[cfg(not(target_arch = "wasm32"))]
+fn default_scan_paths() -> Vec<PathBuf> {
+    vec![paths::desktop_dir(), paths::documents_dir()]
+}
+
+/// Initialize the backend and stores, and install them as globals.
+/// Call once at startup, before opening any window that uses the stores.
 #[cfg(not(target_arch = "wasm32"))]
 pub fn init(db_path: impl AsRef<Path>, cx: &mut App) -> Entity<Backend> {
     // rustls uses the `aws_lc_rs` provider by default; ignore if already installed.
@@ -25,46 +34,64 @@ pub fn init(db_path: impl AsRef<Path>, cx: &mut App) -> Entity<Backend> {
         .install_default()
         .ok();
 
-    let path = db_path.as_ref().to_path_buf();
+    // Initialize the nostr client and universal signer.
     let (client, signer) = cx.foreground_executor().block_on(async move {
+        let path = db_path.as_ref().to_path_buf();
         new_backend(path)
             .await
             .expect("failed to initialize nostr backend")
     });
 
+    // Initialize the backend and stores.
     let entity = cx.new(|cx| Backend::new(client, signer, cx));
     Backend::set_global(entity.clone(), cx);
 
+    // Initialize the profile store.
     ProfileStore::set_global(cx.new(ProfileStore::new), cx);
 
-    // Start the explore list from the local database before the first
-    // window opens; relay syncs continue in the background, so the list
-    // never waits for them.
+    // Start the explore list from the local database before
+    // the first window opens, relay syncs continue in the background,
+    // so the list never waits for them.
     RepoListStore::set_global(cx.new(|cx| RepoListStore::new(None, cx)), cx);
 
-    // The clone cache is only meaningful on native platforms; the wasm
-    // build registers an empty store so `GitStore::global` still works.
+    // The clone cache is only meaningful on native platforms,
+    // the wasm build registers an empty store so `GitStore::global` still works.
     GitStore::set_global(PathBuf::new(), cx);
 
+    // Scan the default directories (Desktop, Documents) for local git
+    // repositories; the sidebar lists them next to the user's NIP-34 repos.
+    LocalReposStore::set_global(
+        cx.new(|cx| LocalReposStore::new(default_scan_paths(), cx)),
+        cx,
+    );
+
     entity
 }
 
 /// Initialize the backend with an in-memory database on wasm.
 #[cfg(target_arch = "wasm32")]
 pub fn init(cx: &mut App) -> Entity<Backend> {
+    // Initialize the nostr client and universal signer.
     let (client, signer) = new_backend().expect("failed to initialize nostr backend");
 
+    // Initialize the backend and stores.
     let entity = cx.new(|cx| Backend::new(client, signer, cx));
     Backend::set_global(entity.clone(), cx);
 
+    // Initialize the profile store.
     ProfileStore::set_global(cx.new(ProfileStore::new), cx);
 
-    // Start the explore list from the local database before the first
-    // window opens; relay syncs continue in the background, so the list
-    // never waits for them.
+    // Start the explore list from the local database before
+    // the first window opens, relay syncs continue in the background,
+    // so the list never waits for them.
     RepoListStore::set_global(cx.new(|cx| RepoListStore::new(None, cx)), cx);
 
+    // The clone cache is only meaningful on native platforms,
+    // the wasm build registers an empty store so `GitStore::global` still works.
     GitStore::set_global(PathBuf::new(), cx);
 
+    // No filesystem scan on wasm: there are no local git repositories.
+    LocalReposStore::set_global(cx.new(|cx| LocalReposStore::new(Vec::new(), cx)), cx);
+
     entity
 }

crates/signed_state/src/local_repos.rs

@@ -0,0 +1,116 @@
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use anyhow::Error;
+use gpui::{App, AppContext, Context, Entity, Global, Task};
+use signed_git::find_git_repos;
+
+struct GlobalLocalReposStore(Entity<LocalReposStore>);
+
+impl Global for GlobalLocalReposStore {}
+
+/// Store of the git repositories discovered under a set of scan paths.
+///
+/// Created at startup by [`crate::init`] with the default scan paths
+/// (the Desktop and Documents folders; empty on wasm, where no scan runs),
+/// then installed as a global so the sidebar can list local repositories.
+/// The scan runs on a background thread; only the results cross back into the entity.
+pub struct LocalReposStore {
+    /// The directories being scanned.
+    pub roots: Arc<Vec<PathBuf>>,
+    /// Git repositories discovered under [`Self::roots`], sorted by path.
+    pub repos: Arc<Vec<PathBuf>>,
+    /// A scan is currently running.
+    pub scanning: bool,
+    /// A scan was requested while one was already running.
+    scan_dirty: bool,
+    tasks: Vec<Task<Result<(), Error>>>,
+}
+
+impl LocalReposStore {
+    /// Retrieve the global local-repositories store
+    /// (created at startup by [`crate::init`]).
+    pub fn global(cx: &App) -> Entity<Self> {
+        cx.global::<GlobalLocalReposStore>().0.clone()
+    }
+
+    pub(crate) fn set_global(entity: Entity<Self>, cx: &mut App) {
+        cx.set_global(GlobalLocalReposStore(entity));
+    }
+
+    /// Create a store scanning `roots` right away
+    /// (a no-op when the list is empty, e.g. on wasm).
+    pub fn new(roots: Vec<PathBuf>, cx: &mut Context<Self>) -> Self {
+        let mut store = Self {
+            roots: Arc::new(roots),
+            repos: Arc::new(Vec::new()),
+            scanning: false,
+            scan_dirty: false,
+            tasks: Vec::new(),
+        };
+        store.rescan(cx);
+        store
+    }
+
+    /// Forget a repository that has just been published to NIP-34, so it
+    /// leaves the local list immediately. A later rescan re-discovers it
+    /// from disk; the sidebar additionally hides published repositories by
+    /// identifier.
+    pub fn remove(&mut self, path: &Path, cx: &mut Context<Self>) {
+        self.repos = Arc::new(
+            self.repos
+                .iter()
+                .filter(|repo| repo.as_path() != path)
+                .cloned()
+                .collect(),
+        );
+        cx.notify();
+    }
+
+    /// Re-run the scan. Requests that arrive while a scan is running are
+    /// folded into one follow-up scan; the results replace the list atomically.
+    pub fn rescan(&mut self, cx: &mut Context<Self>) {
+        if self.scanning {
+            self.scan_dirty = true;
+            return;
+        }
+        if self.roots.is_empty() {
+            return;
+        }
+
+        self.scanning = true;
+        cx.notify();
+
+        let roots = self.roots.clone();
+        let work = cx.background_spawn(async move {
+            let mut repos = Vec::new();
+            for root in roots.iter() {
+                repos.extend(find_git_repos(root));
+            }
+            repos.sort();
+            repos.dedup();
+            repos
+        });
+
+        self.tasks.push(cx.spawn(async move |this, cx| {
+            let repos = work.await;
+            let again = this.update(cx, |this, cx| {
+                this.repos = Arc::new(repos);
+                this.scanning = false;
+                cx.notify();
+
+                let dirty = this.scan_dirty;
+                this.scan_dirty = false;
+                dirty
+            })?;
+
+            // Scans requested while this one was running are coalesced into
+            // a single follow-up scan.
+            if again {
+                this.update(cx, |this, cx| this.rescan(cx))?;
+            }
+
+            Ok(())
+        }));
+    }
+}

crates/signed_state/src/repo.rs

@@ -86,8 +86,13 @@ impl RepoStore {
                     let kind = event.kind == Kind::GitRepoAnnouncement;
                     let author = event.pubkey == this.addr.public_key;
                     let coordinate = event.tags.coordinates().into_iter().any(|c| c == this.addr);
+                    // Locally published deletions may target any event of
+                    // this repository; refresh so they take effect
+                    // immediately, like relay deletions.
+                    let deletion =
+                        event.kind == Kind::EventDeletion || event.kind == Kind::RequestToVanish;
 
-                    coordinate || (kind && author)
+                    coordinate || (kind && author) || deletion
                 }
                 _ => false,
             };

crates/signed_state/src/repo_list.rs

@@ -98,8 +98,14 @@ impl RepoListStore {
                     }
                 }
                 BackendEvent::Published(event) => {
-                    event.kind == Kind::GitRepoAnnouncement
-                        && this.author.is_none_or(|a| a == event.pubkey)
+                    let announcement = event.kind == Kind::GitRepoAnnouncement
+                        && this.author.is_none_or(|a| a == event.pubkey);
+                    // Locally published deletions (e.g. deleting a repo)
+                    // are already in the local database; refresh so they
+                    // take effect immediately, like relay deletions.
+                    let deletion =
+                        event.kind == Kind::EventDeletion || event.kind == Kind::RequestToVanish;
+                    announcement || deletion
                 }
                 BackendEvent::Synced | BackendEvent::SyncProgress { .. } => true,
                 _ => false,