tuiからセッションを復帰する経路の実装

crates/pod/Cargo.toml

@@ -12,6 +12,7 @@ session-store = { version = "0.1.0", path = "../session-store" }
 manifest = { version = "0.1.0", path = "../manifest" }
 protocol = { version = "0.1.0", path = "../protocol" }
 provider = { version = "0.1.0", path = "../provider" }
+scope-lock = { version = "0.1.0", path = "../scope-lock" }
 serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.149"
 thiserror = "2.0"

crates/pod/src/main.rs

@@ -44,9 +44,9 @@ struct Cli {
     #[arg(long, value_name = "PATH", requires = "adopt")]
     callback: Option<PathBuf>,
 
-    /// Restore a Pod from an existing session. The source session log
-    /// is forked at its head into a new session id, so the original
-    /// jsonl is left untouched and double-write races are impossible.
+    /// Restore a Pod from an existing session. The Pod re-uses the
+    /// given session id and appends new turns to the same jsonl;
+    /// concurrent writers are prevented by the `scope.lock` registry.
     /// Mutually exclusive with `--adopt` (spawned children always start
     /// fresh).
     #[arg(long, value_name = "UUID", conflicts_with = "adopt")]

crates/pod/src/pod.rs

@@ -100,10 +100,11 @@ pub struct Pod<C: LlmClient, St: Store> {
     /// PodInterceptor installed in `ensure_interceptor_installed`.
     pending_notifies: NotifyBuffer,
     /// Scope allocation in the machine-wide lock file. `Some` for
-    /// Pods built via `from_manifest` (production path); `None` for
-    /// lower-level constructors (`Pod::new`, `Pod::restore`) that
-    /// bypass the registry. Kept purely for its `Drop` impl, which
-    /// releases the allocation when the Pod is dropped.
+    /// Pods built via `from_manifest` / `from_manifest_spawned` /
+    /// `restore_from_manifest` (production paths); `None` for the
+    /// low-level `Pod::new` constructor used in tests, which bypasses
+    /// the registry. Kept purely for its `Drop` impl, which releases
+    /// the allocation when the Pod is dropped.
     #[allow(dead_code)]
     scope_allocation: Option<ScopeAllocationGuard>,
     /// Socket path of the spawning Pod. `Some` only for Pods built via
@@ -717,6 +718,7 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
             self.head_hash = Some(hash);
             return Ok(());
         }
+        let prev_session_id = self.session_id;
         session_store::ensure_head_or_fork(
             &self.store,
             &mut self.session_id,
@@ -724,6 +726,13 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
             state,
         )
         .await?;
+        // ensure_head_or_fork mints a fresh session_id when it auto-
+        // forks. Sync that to scope.lock so a concurrent
+        // restore_from_manifest can't see "no live writer" for the new
+        // session and grab it.
+        if self.session_id != prev_session_id && self.scope_allocation.is_some() {
+            scope_lock::update_session(&self.manifest.pod.name, self.session_id)?;
+        }
         Ok(())
     }
 
@@ -1155,6 +1164,15 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
         // until its first LLM call.
         self.session_id = new_session_id;
         self.head_hash = Some(new_head_hash);
+        // Keep scope.lock pointing at the live session_id. Without this
+        // a concurrent `restore_from_manifest(new_session_id)` would
+        // see no live writer and grab the session this Pod just moved
+        // into, causing two writers to race on the same jsonl. Skipped
+        // when no allocation is installed (e.g. compact under
+        // `Pod::new` in tests).
+        if self.scope_allocation.is_some() {
+            scope_lock::update_session(&self.manifest.pod.name, new_session_id)?;
+        }
         let worker = self.worker.as_mut().unwrap();
         worker.set_history(new_history);
         // Anchor the prompt cache at the summary item so that Anthropic
@@ -1602,15 +1620,6 @@ impl<St: Store> Pod<Box<dyn LlmClient>, St> {
         store: St,
         loader: PromptLoader,
     ) -> Result<Self, PodError> {
-        // Refuse to resume into a session that's already being written.
-        if let Some(info) = scope_lock::lookup_session(session_id)? {
-            return Err(PodError::SessionInUse {
-                session_id,
-                pod_name: info.pod_name,
-                socket: info.socket,
-            });
-        }
-
         let state = session_store::restore(&store, session_id).await?;
         if state.head_hash.is_none() {
             return Err(PodError::SessionEmpty { session_id });
@@ -1618,6 +1627,11 @@ impl<St: Store> Pod<Box<dyn LlmClient>, St> {
 
         let common = prepare_pod_common(&manifest, &loader, /* parse_template */ false)?;
 
+        // Atomic: register_pod inside install_top_level rejects when
+        // another live allocation already holds `session_id`. Wrapping
+        // the lookup + install inside a single `LockFileGuard` is what
+        // makes "no two live Pods write to the same session log"
+        // actually structural rather than a hopeful pre-check.
         let socket_path = dir::default_base()
             .map_err(ScopeLockError::from)?
             .join(&manifest.pod.name)
@@ -1883,16 +1897,6 @@ pub enum PodError {
     #[error("memory Phase 1 staging write failed: {0}")]
     ExtractStaging(#[source] memory::extract::StagingError),
 
-    #[error(
-        "session {session_id} is currently in use by pod `{pod_name}` at {}",
-        .socket.display()
-    )]
-    SessionInUse {
-        session_id: SessionId,
-        pod_name: String,
-        socket: PathBuf,
-    },
-
     #[error("session {session_id} has no entries to restore")]
     SessionEmpty { session_id: SessionId },
 }

crates/pod/src/runtime/mod.rs

@@ -1,2 +1,2 @@
 pub mod dir;
-pub mod scope_lock;
+pub use ::scope_lock;

crates/pod/src/spawn/tool.rs

@@ -441,7 +441,8 @@ fn scope_lock_err_to_tool(e: ScopeLockError) -> ToolError {
         ScopeLockError::NotSubset { .. }
         | ScopeLockError::WriteConflict { .. }
         | ScopeLockError::DuplicatePodName(_)
-        | ScopeLockError::UnknownPod(_) => ToolError::InvalidArgument(e.to_string()),
+        | ScopeLockError::UnknownPod(_)
+        | ScopeLockError::SessionConflict { .. } => ToolError::InvalidArgument(e.to_string()),
         ScopeLockError::Io(_) => ToolError::ExecutionFailed(e.to_string()),
     }
 }

crates/pod/tests/restore_test.rs

@@ -0,0 +1,86 @@
+//! Integration tests for `Pod::restore_from_manifest`'s pre-build
+//! validation paths.
+//!
+//! These cases all return before `prepare_pod_common` runs, so they
+//! do not need a real LLM client or scope-lock environment — only the
+//! session store needs to be present.
+
+use std::sync::{LazyLock, Mutex};
+
+use pod::{Pod, PodError};
+use session_store::{FsStore, SessionId, StoreError};
+
+const MINIMAL_MANIFEST_TOML: &str = r#"
+[pod]
+name = "restore-test"
+pwd = "./"
+
+[model]
+scheme = "anthropic"
+model_id = "test-model"
+
+[worker]
+max_tokens = 100
+
+[[scope.allow]]
+target = "./"
+permission = "write"
+"#;
+
+/// Serialises tests that mutate runtime-dir env vars, mirroring the
+/// pattern used by other integration tests in this crate.
+static ENV_LOCK: LazyLock<Mutex<()>> = LazyLock::new(|| Mutex::new(()));
+
+#[tokio::test]
+async fn restore_from_manifest_rejects_unknown_session() {
+    let _lock = ENV_LOCK.lock().unwrap_or_else(|e| e.into_inner());
+
+    let store_tmp = tempfile::tempdir().unwrap();
+    let store = FsStore::new(store_tmp.path()).await.unwrap();
+    let manifest = pod::PodManifest::from_toml(MINIMAL_MANIFEST_TOML).unwrap();
+
+    // A freshly-minted id with no jsonl file at all → store returns
+    // NotFound, which `Pod::restore_from_manifest` surfaces verbatim
+    // as `PodError::Store`.
+    let unknown = session_store::new_session_id();
+    let result = Pod::restore_from_manifest(
+        unknown,
+        manifest,
+        store,
+        pod::PromptLoader::builtins_only(),
+    )
+    .await;
+
+    match result {
+        Err(PodError::Store(StoreError::NotFound(id))) => assert_eq!(id, unknown),
+        Err(other) => panic!("expected Store(NotFound), got {other:?}"),
+        Ok(_) => panic!("expected unknown session to fail"),
+    }
+}
+
+#[tokio::test]
+async fn restore_from_manifest_rejects_empty_session_log() {
+    let _lock = ENV_LOCK.lock().unwrap_or_else(|e| e.into_inner());
+
+    let store_tmp = tempfile::tempdir().unwrap();
+    let store = FsStore::new(store_tmp.path()).await.unwrap();
+    let manifest = pod::PodManifest::from_toml(MINIMAL_MANIFEST_TOML).unwrap();
+
+    // Pre-create an empty `<id>.jsonl` so `read_all` succeeds with no
+    // entries. `collect_state` returns `head_hash = None`, which
+    // `restore_from_manifest` rejects with `SessionEmpty` *before* it
+    // gets as far as building the LLM client — so the test does not
+    // need credentials or a runtime sandbox.
+    let id: SessionId = session_store::new_session_id();
+    let path = store_tmp.path().join(format!("{id}.jsonl"));
+    std::fs::write(&path, b"").unwrap();
+
+    let result =
+        Pod::restore_from_manifest(id, manifest, store, pod::PromptLoader::builtins_only()).await;
+
+    match result {
+        Err(PodError::SessionEmpty { session_id }) => assert_eq!(session_id, id),
+        Err(other) => panic!("expected SessionEmpty, got {other:?}"),
+        Ok(_) => panic!("expected empty session log to fail"),
+    }
+}

crates/scope-lock/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "scope-lock"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+fs4 = { version = "0.13.1", features = ["sync"] }
+libc = "0.2.185"
+manifest = { version = "0.1.0", path = "../manifest" }
+serde = { version = "1.0.228", features = ["derive"] }
+serde_json = "1.0.149"
+session-store = { version = "0.1.0", path = "../session-store" }
+thiserror = "2.0"
+
+[dev-dependencies]
+tempfile = "3.27.0"

crates/scope-lock/src/lib.rs

@@ -303,6 +303,10 @@ fn find_conflict_in_subtree(
 /// Register a top-level Pod (started directly by a human, no
 /// delegation parent). Reclaims stale entries before checking
 /// conflicts so a crashed Pod's allocation doesn't block the new one.
+///
+/// Rejects when another live allocation is already writing to
+/// `session_id`, so two `restore_from_manifest` calls under different
+/// `pod_name`s cannot both grab the same session log.
 pub fn register_pod(
     guard: &mut LockFileGuard,
     pod_name: String,
@@ -315,6 +319,13 @@ pub fn register_pod(
     if guard.data().find(&pod_name).is_some() {
         return Err(ScopeLockError::DuplicatePodName(pod_name));
     }
+    if let Some(existing) = guard.data().find_by_session(session_id) {
+        return Err(ScopeLockError::SessionConflict {
+            session_id,
+            pod_name: existing.pod_name.clone(),
+            socket: existing.socket.clone(),
+        });
+    }
     for rule in scope_allow
         .iter()
         .filter(|r| r.permission == Permission::Write)
@@ -550,6 +561,46 @@ pub fn adopt_allocation(
     })
 }
 
+/// Rewrite the `session_id` recorded for `pod_name` to
+/// `new_session_id`.
+///
+/// The Pod's in-memory `session_id` can change underneath the
+/// allocation in two normal places:
+///
+/// - `Pod::compact` mints a fresh session and swaps it in.
+/// - `session_store::ensure_head_or_fork` auto-forks when another
+///   writer has advanced the store head behind our back.
+///
+/// Both paths must call this so subsequent `lookup_session` queries
+/// find the live session id, not the old one. Without this update a
+/// concurrent `restore_from_manifest(new_id)` would see "no live
+/// writer" and proceed to register a competing allocation on the
+/// session this Pod just moved into.
+///
+/// The lock is opened once and the allocation is rewritten inside the
+/// guard, so the session_id collision check is atomic with the
+/// rewrite.
+pub fn update_session(pod_name: &str, new_session_id: SessionId) -> Result<(), ScopeLockError> {
+    let lock_path = default_lock_path()?;
+    let mut guard = LockFileGuard::open(&lock_path)?;
+    if let Some(other) = guard.data().find_by_session(new_session_id) {
+        if other.pod_name != pod_name {
+            return Err(ScopeLockError::SessionConflict {
+                session_id: new_session_id,
+                pod_name: other.pod_name.clone(),
+                socket: other.socket.clone(),
+            });
+        }
+    }
+    let alloc = guard
+        .data_mut()
+        .find_mut(pod_name)
+        .ok_or_else(|| ScopeLockError::UnknownPod(pod_name.into()))?;
+    alloc.session_id = Some(new_session_id);
+    guard.save()?;
+    Ok(())
+}
+
 /// Information about a Pod that currently holds an allocation for a
 /// given session.
 #[derive(Debug, Clone)]
@@ -593,6 +644,15 @@ pub enum ScopeLockError {
     NotSubset { spawner: String, rule: ScopeRule },
     #[error("pod `{0}` is not registered")]
     UnknownPod(String),
+    #[error(
+        "session {session_id} is already held by pod `{pod_name}` at {}",
+        .socket.display()
+    )]
+    SessionConflict {
+        session_id: SessionId,
+        pod_name: String,
+        socket: PathBuf,
+    },
 }
 
 #[cfg(test)]
@@ -1200,4 +1260,164 @@ mod tests {
             other => panic!("expected WriteConflict, got {other:?}"),
         }
     }
+
+    #[test]
+    fn find_by_session_skips_none_placeholders() {
+        let dir = TempDir::new().unwrap();
+        let path = dir.path().join("scope.lock");
+        let mut g = open_empty(&path);
+        // Pre-reservation: delegate_scope leaves session_id = None
+        // until adopt_allocation rewrites it. find_by_session must not
+        // match those placeholders, otherwise a freshly-spawning child
+        // would shadow itself before it has even chosen a session.
+        register_pod(
+            &mut g,
+            "parent".into(),
+            std::process::id(),
+            sock("parent"),
+            vec![write_rule("/p", true)],
+            sid(),
+        )
+        .unwrap();
+        delegate_scope(
+            &mut g,
+            "parent",
+            "child".into(),
+            std::process::id(),
+            sock("child"),
+            vec![write_rule("/p/sub", true)],
+        )
+        .unwrap();
+
+        let target_session = sid();
+        // The placeholder allocation has session_id = None and must
+        // not be returned for any lookup.
+        assert!(g.data().find_by_session(target_session).is_none());
+
+        // After adopt-style rewrite, the same allocation is now found.
+        g.data_mut()
+            .find_mut("child")
+            .unwrap()
+            .session_id = Some(target_session);
+        let found = g.data().find_by_session(target_session).unwrap();
+        assert_eq!(found.pod_name, "child");
+    }
+
+    #[test]
+    fn register_pod_rejects_session_id_collision() {
+        let dir = TempDir::new().unwrap();
+        let path = dir.path().join("scope.lock");
+        let mut g = open_empty(&path);
+        let shared_session = sid();
+        register_pod(
+            &mut g,
+            "first".into(),
+            std::process::id(),
+            sock("first"),
+            vec![write_rule("/work/a", true)],
+            shared_session,
+        )
+        .unwrap();
+        // Second registration tries to grab the same session_id under
+        // a different pod_name. Without the SessionConflict check both
+        // would succeed and race on the same jsonl.
+        let err = register_pod(
+            &mut g,
+            "second".into(),
+            std::process::id(),
+            sock("second"),
+            vec![write_rule("/work/b", true)],
+            shared_session,
+        )
+        .unwrap_err();
+        match err {
+            ScopeLockError::SessionConflict {
+                session_id,
+                pod_name,
+                ..
+            } => {
+                assert_eq!(session_id, shared_session);
+                assert_eq!(pod_name, "first");
+            }
+            other => panic!("expected SessionConflict, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn lookup_session_returns_live_writer_info() {
+        let dir = TempDir::new().unwrap();
+        let _sandbox = RuntimeDirSandbox::new(dir.path());
+        let s = sid();
+        let guard = install_top_level(
+            "live".into(),
+            std::process::id(),
+            sock("live"),
+            vec![write_rule("/work", true)],
+            s,
+        )
+        .unwrap();
+        let info = lookup_session(s).unwrap().expect("expected live writer");
+        assert_eq!(info.pod_name, "live");
+        assert_eq!(info.socket, sock("live"));
+        drop(guard);
+        // After the guard's release, the lookup goes back to None.
+        assert!(lookup_session(s).unwrap().is_none());
+    }
+
+    #[test]
+    fn update_session_rewrites_allocation_session_id() {
+        let dir = TempDir::new().unwrap();
+        let _sandbox = RuntimeDirSandbox::new(dir.path());
+        let original = sid();
+        let updated = sid();
+        let _guard = install_top_level(
+            "p".into(),
+            std::process::id(),
+            sock("p"),
+            vec![write_rule("/work", true)],
+            original,
+        )
+        .unwrap();
+        update_session("p", updated).unwrap();
+        // lookup against the original is now empty, the updated id wins.
+        assert!(lookup_session(original).unwrap().is_none());
+        assert_eq!(lookup_session(updated).unwrap().unwrap().pod_name, "p");
+    }
+
+    #[test]
+    fn update_session_rejects_when_target_already_held() {
+        let dir = TempDir::new().unwrap();
+        let _sandbox = RuntimeDirSandbox::new(dir.path());
+        let s_a = sid();
+        let s_b = sid();
+        let _g_a = install_top_level(
+            "a".into(),
+            std::process::id(),
+            sock("a"),
+            vec![write_rule("/work/a", true)],
+            s_a,
+        )
+        .unwrap();
+        let _g_b = install_top_level(
+            "b".into(),
+            std::process::id(),
+            sock("b"),
+            vec![write_rule("/work/b", true)],
+            s_b,
+        )
+        .unwrap();
+        // `a` cannot adopt b's live session id.
+        let err = update_session("a", s_b).unwrap_err();
+        match err {
+            ScopeLockError::SessionConflict {
+                pod_name,
+                session_id,
+                ..
+            } => {
+                assert_eq!(pod_name, "b");
+                assert_eq!(session_id, s_b);
+            }
+            other => panic!("expected SessionConflict, got {other:?}"),
+        }
+    }
 }

crates/tui/Cargo.toml

@@ -15,3 +15,4 @@ uuid = "1.23"
 toml = "1.1.2"
 manifest = { version = "0.1.0", path = "../manifest" }
 session-store = { version = "0.1.0", path = "../session-store" }
+scope-lock = { version = "0.1.0", path = "../scope-lock" }

crates/tui/src/picker.rs

@@ -19,6 +19,7 @@ use ratatui::style::{Color, Modifier, Style};
 use ratatui::text::{Line, Span};
 use ratatui::widgets::Paragraph;
 use ratatui::{Frame, TerminalOptions, Viewport};
+use scope_lock::lookup_session;
 use session_store::{
     ContentPart, FsStore, HashedEntry, Item, LogEntry, SessionId, Store,
 };
@@ -71,6 +72,11 @@ struct Row {
     id: SessionId,
     /// Last user / assistant snippet, or a `[corrupt]` placeholder.
     preview: String,
+    /// `Some(pod_name)` when a live Pod currently holds an allocation
+    /// for this session in `scope.lock`. Picking such a row launches
+    /// `pod --session <UUID>` which will fail with `SessionConflict` —
+    /// the badge warns the user up-front.
+    live_pod: Option<String>,
 }
 
 pub async fn run() -> Result<PickerOutcome, PickerError> {
@@ -82,7 +88,15 @@ pub async fn run() -> Result<PickerOutcome, PickerError> {
     let mut rows: Vec<Row> = Vec::with_capacity(MAX_ROWS);
     for id in ids.into_iter().take(MAX_ROWS) {
         let preview = build_preview(&store, id).await;
-        rows.push(Row { id, preview });
+        // Best-effort live check. A scope.lock I/O hiccup downgrades
+        // the row to "no badge" rather than killing the picker — the
+        // user still gets to see the listing.
+        let live_pod = lookup_session(id).ok().flatten().map(|info| info.pod_name);
+        rows.push(Row {
+            id,
+            preview,
+            live_pod,
+        });
     }
 
     let mut selected = 0usize;
@@ -291,12 +305,19 @@ fn row_line(row: &Row, selected: bool) -> Line<'_> {
     } else {
         Style::default().fg(Color::DarkGray)
     };
-    Line::from(vec![
+    let mut spans = vec![
         Span::raw(marker),
         Span::styled(short_session(row.id), id_style),
         Span::raw("  "),
-        Span::styled(row.preview.clone(), preview_style),
-    ])
+    ];
+    if let Some(ref pod_name) = row.live_pod {
+        spans.push(Span::styled(
+            format!("[live: {pod_name}] "),
+            Style::default().fg(Color::Red).add_modifier(Modifier::BOLD),
+        ));
+    }
+    spans.push(Span::styled(row.preview.clone(), preview_style));
+    Line::from(spans)
 }
 
 fn short_session(id: SessionId) -> String {

crates/tui/src/spawn.rs

@@ -447,8 +447,8 @@ struct Form {
     editing: bool,
     /// `Some(id)` flips the dialog into "Resume Pod" mode: the title
     /// switches, the source session is shown to the user, and the
-    /// child pod is launched with `--session <id>` so it forks and
-    /// restores `id`.
+    /// child pod is launched with `--session <id>` so it restores
+    /// from `id` and appends to the same session log.
     resume_from: Option<SessionId>,
 }