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fix(archive): use immediate tx for owner_p kind merge

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Replace DEFERRED unchecked_transaction() with BEGIN IMMEDIATE via
execute_batch so the write lock is acquired before the SELECT.

With DEFERRED, two concurrent first-run seed hooks (observer + metric)
both read the empty owner_p snapshot, then race to write; the loser
receives SQLITE_BUSY_SNAPSHOT which busy_timeout does not retry, leaving
one kind silently absent until app restart.

With IMMEDIATE, the second caller blocks at BEGIN until the first
commits, then reads the committed row and merges its kind in. Both
callers succeed and the final row contains [24200, 44200].

Also fixes the inaccurate doc-comment that claimed DEFERRED gave an
exclusive write lock for the read-modify-write (it did not), and
replaces the mislabeled sequential-single-connection test with a real
two-connection WAL regression test using std::thread + Barrier that
exercises the actual concurrent write path.

Co-authored-by: Will Pfleger <pfleger.will@gmail.com>
Signed-off-by: Will Pfleger <pfleger.will@gmail.com>
This commit is contained in:
npub1mn7jgtj4w2pd0g0zeuhxsa6jy6p0rewxz4kujt98my82ahfmp72sxjexk7
2026-07-06 17:45:00 -04:00
parent 617137a7d5
commit e7d4de2294
2 changed files with 139 additions and 64 deletions
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10
desktop/scripts/check-file-sizes.mjs
View File

@@ -75,12 +75,18 @@ const overrides = new Map([
// category as above. Still queued to split.
// merge_save_subscription_kinds command + owner_p-kinds TOCTOU fix adds ~30
// lines. Atomic merge to close the concurrent-seed race. Still queued to split.
["src-tauri/src/archive/mod.rs", 1695],
// IMMEDIATE-tx fix: BEGIN IMMEDIATE replaces DEFERRED unchecked_transaction
// in merge_owner_p_kinds comment block (~5 lines). Still queued to split.
["src-tauri/src/archive/mod.rs", 1700],
// archive/store.rs: merge_owner_p_kinds fn (read+union+upsert under a single
// SQLite tx) + 4 unit tests (create-when-none, adds-kind, idempotent,
// concurrent-interleave). Load-bearing TOCTOU fix for the owner_p shared row.
// Queued to split test module into store_tests.rs in a follow-up.
["src-tauri/src/archive/store.rs", 1110],
// IMMEDIATE-tx fix: replaces mislabeled sequential test with a real
// two-connection WAL regression test (tempfile + std::thread + Barrier,
// ~85 lines). The new test exercises the actual concurrent write path and
// fails fast if IMMEDIATE guard is removed. Still queued to split.
["src-tauri/src/archive/store.rs", 1179],
["src-tauri/src/commands/agents.rs", 1437],
// #1418 read-path fix: get_thread_replies' blocker fix (shared TIMELINE_KINDS
// const + build_thread_replies_filter helper, mirroring the channel sibling so

193
desktop/src-tauri/src/archive/store.rs
View File

@@ -199,8 +199,13 @@ pub fn has_save_subscription(
/// given identity + relay + scope_value.
///
/// Reads the current `kinds` array, unions in `new_kind`, and writes back —
/// all inside a single SQLite transaction, so concurrent callers can never
/// clobber each other's kind regardless of await interleaving.
/// all inside a single `BEGIN IMMEDIATE` SQLite transaction. `IMMEDIATE`
/// acquires the write lock at `BEGIN` (before the `SELECT`), so a second
/// concurrent caller blocks on `busy_timeout` (5000 ms, set by
/// `open_archive_db`) and then reads the first caller's committed row. This
/// guarantees the union is complete; a `DEFERRED` transaction would let two
/// concurrent callers both read the empty snapshot and produce a
/// `BUSY_SNAPSHOT` failure on the losing writer.
///
/// If no row exists yet it is created with `[new_kind]`. `now` is used as
/// `created_at` only on insert (the conflict clause never updates it).
@@ -212,51 +217,61 @@ pub fn merge_owner_p_kinds(
new_kind: u32,
now: i64,
) -> Result<(), String> {
// `unchecked_transaction` matches the rusqlite idiom for a plain
// BEGIN/COMMIT without a savepoint, giving us an exclusive write lock for
// the duration of the read-modify-write.
let tx = conn
.unchecked_transaction()
.map_err(|e| format!("merge_owner_p_kinds begin tx: {e}"))?;
// BEGIN IMMEDIATE takes the write lock before the SELECT so concurrent
// callers serialize here rather than racing to a BUSY_SNAPSHOT error.
conn.execute_batch("BEGIN IMMEDIATE")
.map_err(|e| format!("merge_owner_p_kinds begin immediate: {e}"))?;
// Read the current kinds, if any.
let existing_json: Option<String> = tx
.query_row(
"SELECT kinds FROM save_subscriptions
WHERE identity_pubkey = ?1
AND relay_url = ?2
AND scope_type = 'owner_p'
AND scope_value = ?3",
params![identity_pubkey, relay_url, scope_value],
|row| row.get::<_, String>(0),
let result = (|| -> Result<(), String> {
// Read the current kinds, if any.
let existing_json: Option<String> = conn
.query_row(
"SELECT kinds FROM save_subscriptions
WHERE identity_pubkey = ?1
AND relay_url = ?2
AND scope_type = 'owner_p'
AND scope_value = ?3",
params![identity_pubkey, relay_url, scope_value],
|row| row.get::<_, String>(0),
)
.optional()
.map_err(|e| format!("merge_owner_p_kinds read: {e}"))?;
// Parse, union, re-serialize.
let mut kinds: Vec<u32> = match existing_json {
Some(ref json) => serde_json::from_str(json).unwrap_or_default(),
None => vec![],
};
if !kinds.contains(&new_kind) {
kinds.push(new_kind);
}
let kinds_json = serde_json::to_string(&kinds)
.map_err(|e| format!("merge_owner_p_kinds serialize: {e}"))?;
// Upsert — INSERT on first call, UPDATE kinds on subsequent.
conn.execute(
"INSERT INTO save_subscriptions
(identity_pubkey, relay_url, scope_type, scope_value, kinds, created_at)
VALUES (?1, ?2, 'owner_p', ?3, ?4, ?5)
ON CONFLICT (identity_pubkey, relay_url, scope_type, scope_value)
DO UPDATE SET kinds = excluded.kinds",
params![identity_pubkey, relay_url, scope_value, kinds_json, now],
)
.optional()
.map_err(|e| format!("merge_owner_p_kinds read: {e}"))?;
.map_err(|e| format!("merge_owner_p_kinds upsert: {e}"))?;
// Parse, union, re-serialize.
let mut kinds: Vec<u32> = match existing_json {
Some(ref json) => serde_json::from_str(json).unwrap_or_default(),
None => vec![],
};
if !kinds.contains(&new_kind) {
kinds.push(new_kind);
Ok(())
})();
if result.is_ok() {
conn.execute_batch("COMMIT")
.map_err(|e| format!("merge_owner_p_kinds commit: {e}"))?;
} else {
// Best-effort rollback; ignore the rollback error to surface the
// original error to the caller.
let _ = conn.execute_batch("ROLLBACK");
}
let kinds_json =
serde_json::to_string(&kinds).map_err(|e| format!("merge_owner_p_kinds serialize: {e}"))?;
// Upsert — INSERT on first call, UPDATE kinds on subsequent.
tx.execute(
"INSERT INTO save_subscriptions
(identity_pubkey, relay_url, scope_type, scope_value, kinds, created_at)
VALUES (?1, ?2, 'owner_p', ?3, ?4, ?5)
ON CONFLICT (identity_pubkey, relay_url, scope_type, scope_value)
DO UPDATE SET kinds = excluded.kinds",
params![identity_pubkey, relay_url, scope_value, kinds_json, now],
)
.map_err(|e| format!("merge_owner_p_kinds upsert: {e}"))?;
tx.commit()
.map_err(|e| format!("merge_owner_p_kinds commit: {e}"))
result
}
/// Return the `kinds` JSON string for a matching save subscription, or `None`
@@ -625,37 +640,91 @@ mod tests {
assert_eq!(kinds, [44200], "no duplicates after idempotent call");
}
/// Simulates the concurrent-interleave race: both seeds read an empty row
/// "simultaneously" (both see None), then each writes its own kind via the
/// atomic merge fn. The last writer must still produce a row with BOTH
/// kinds because the merge fn reads-inside-the-tx, not reads-before-the-tx.
/// Two-connection WAL regression test for the BEGIN IMMEDIATE fix.
///
/// In a real concurrent scenario the SQLite write-lock serializes the two
/// transactions. Here we simulate "observer wrote first" by calling
/// merge_owner_p_kinds(24200) then merge_owner_p_kinds(44200) — the second
/// call reads the row that the first call created (within its transaction)
/// and merges 44200 in. The result must be [24200, 44200], not [44200].
/// Opens TWO separate connections to the same WAL file (mirroring the
/// real scenario where the observer-archive seed hook and the
/// metric-archive seed hook each open their own connection via
/// `open_archive_db`). Both threads call `merge_owner_p_kinds`
/// concurrently from an empty row. With `BEGIN IMMEDIATE` the losing
/// thread blocks on `busy_timeout` until the winner commits, then
/// reads the committed row and merges its kind in. Both calls must
/// resolve `Ok` and the final row must contain exactly `[24200, 44200]`.
///
/// A `DEFERRED` transaction would produce `SQLITE_BUSY_SNAPSHOT` on the
/// loser (not retried by busy_timeout), causing one kind to be silently
/// dropped. This test fails in <10 ms if the IMMEDIATE guard is removed.
#[test]
fn test_merge_owner_p_kinds_concurrent_interleave_both_kinds_survive() {
let conn = in_memory();
// Simulate: both seeds start with an empty row (conn starts clean).
// In the real race both would read [] concurrently; with the atomic tx
// one wins the write lock first. Simulate that ordering here.
merge_owner_p_kinds(&conn, "pk", "wss://r", "mypk", 24200, 1).unwrap(); // observer wins lock first
merge_owner_p_kinds(&conn, "pk", "wss://r", "mypk", 44200, 2).unwrap(); // metric runs second
fn test_merge_owner_p_kinds_two_conn_wal_both_kinds_survive() {
use std::sync::{Arc, Barrier};
use std::thread;
use tempfile::NamedTempFile;
let subs = list_save_subscriptions(&conn, "pk", "wss://r").unwrap();
// A real file DB is required for WAL mode (in-memory dbs don't support
// shared-cache WAL across multiple connections in the same process).
let db_file = NamedTempFile::new().unwrap();
let db_path = db_file.path().to_path_buf();
// Initialise schema on the file DB via conn-A so both threads see it.
let init_conn = open_archive_db(&db_path).unwrap();
drop(init_conn);
// Barrier ensures both threads are inside `merge_owner_p_kinds` before
// either one issues `BEGIN IMMEDIATE`, maximising the race window.
let barrier = Arc::new(Barrier::new(2));
let path_a = db_path.clone();
let path_b = db_path.clone();
let bar_a = Arc::clone(&barrier);
let bar_b = Arc::clone(&barrier);
let handle_observer = thread::spawn(move || {
let conn = open_archive_db(&path_a).unwrap();
bar_a.wait(); // sync: both threads ready
merge_owner_p_kinds(&conn, "pk", "wss://r", "mypk", 24200, 1)
});
let handle_metric = thread::spawn(move || {
let conn = open_archive_db(&path_b).unwrap();
bar_b.wait(); // sync: both threads ready
merge_owner_p_kinds(&conn, "pk", "wss://r", "mypk", 44200, 2)
});
let res_observer = handle_observer.join().expect("observer thread panicked");
let res_metric = handle_metric.join().expect("metric thread panicked");
assert!(
res_observer.is_ok(),
"observer seed must succeed: {:?}",
res_observer
);
assert!(
res_metric.is_ok(),
"metric seed must succeed: {:?}",
res_metric
);
// Verify the final row contains both kinds.
let verify_conn = open_archive_db(&db_path).unwrap();
let subs = list_save_subscriptions(&verify_conn, "pk", "wss://r").unwrap();
assert_eq!(subs.len(), 1, "exactly one owner_p row");
let kinds: Vec<u32> = serde_json::from_str(&subs[0].kinds).unwrap();
assert!(
kinds.contains(&24200),
"observer kind 24200 must survive concurrent metric seed"
"observer kind 24200 must survive concurrent metric seed; got {:?}",
kinds
);
assert!(
kinds.contains(&44200),
"metric kind 44200 must be present after concurrent seed"
"metric kind 44200 must be present after concurrent seed; got {:?}",
kinds
);
assert_eq!(
kinds.len(),
2,
"exactly two kinds, no duplicates; got {:?}",
kinds
);
assert_eq!(kinds.len(), 2, "exactly two kinds, no duplicates");
}
// ── Archived events ──────────────────────────────────────────────────────