From 05c82c2362b564940e1dfb8d667b905e31071382 Mon Sep 17 00:00:00 2001
From: Bryan Van Deusen <bryan.vandeusen@fabledsword.com>
Date: Wed, 7 Oct 2026 19:57:24 -0400
Subject: [PATCH] core, desktop: Db::conn everywhere, Change::default,
 notes_where, and shared row mappings

From the audit (#5179, core and desktop half).

- Every `db.0.lock().map_err(|e| e.to_string())?` (about 50 sites in core and
  the desktop) is now `db.conn()?`. The few sites that deliberately handle
  a poisoned lock differently, and the tests, keep their own spelling.
- push::Change derives Default, so its four constructors name only the
  fields they set.
- store: list_notes, reminders, titles and search share notes_where (ids
  from a query, each loaded through load_note). Labels share
  LABEL_SELECT/label_row, and saved filters share
  SAVED_FILTER_SELECT/saved_filter_row.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 core/src/local/mod.rs                   |   9 +-
 core/src/local/store.rs                 | 158 +++++++++++-------------
 core/src/sync/engine.rs                 |   4 +-
 core/src/sync/pull.rs                   |   6 +-
 core/src/sync/push.rs                   |  47 ++-----
 core/src/sync/sharing.rs                |   4 +-
 desktop/src-tauri/src/autosync.rs       |   4 +-
 desktop/src-tauri/src/capture.rs        |   4 +-
 desktop/src-tauri/src/commands/local.rs |  62 +++++-----
 desktop/src-tauri/src/commands/sync.rs  |  10 +-
 desktop/src-tauri/src/reminders.rs      |   2 +-
 desktop/src-tauri/src/update.rs         |   6 +-
 12 files changed, 132 insertions(+), 184 deletions(-)

diff --git a/core/src/local/mod.rs b/core/src/local/mod.rs
index e5c71e7..bd1ce4e 100644
--- a/core/src/local/mod.rs
+++ b/core/src/local/mod.rs
@@ -26,12 +26,9 @@ pub struct Db(pub Mutex<Connection>);
 impl Db {
     /// Lock the store, reporting a poisoned lock as a message rather than a panic.
     ///
-    /// Every consumer was writing `db.0.lock().map_err(|e| e.to_string())?` at each
-    /// call site. Beyond the repetition, that spelling forces the caller to NAME
-    /// `rusqlite::Connection` in any helper that returns the guard — which would make
-    /// rusqlite a dependency of a layer whose whole point is not to know what the
-    /// store is made of. Returning it from here means callers can bind the guard by
-    /// inference and never name the type.
+    /// The one way every caller takes the lock. Returning the guard from here lets a
+    /// caller bind it by inference without naming `rusqlite::Connection`, so layers
+    /// above the store need not depend on what it is made of.
     ///
     /// A poisoned lock means some earlier call panicked while holding it. The store
     /// is not necessarily corrupt, but this connection can't be trusted blind, so it
diff --git a/core/src/local/store.rs b/core/src/local/store.rs
index 456fe15..ef1e9c3 100644
--- a/core/src/local/store.rs
+++ b/core/src/local/store.rs
@@ -8,7 +8,7 @@
 //! up with the values the frontend sends.
 
 use chrono::{DateTime, Duration, SecondsFormat, Utc};
-use rusqlite::{params, params_from_iter, Connection, OptionalExtension};
+use rusqlite::{params, params_from_iter, Connection, OptionalExtension, Params};
 use serde_json::{json, Value};
 use uuid::Uuid;
 
@@ -439,9 +439,16 @@ pub fn list_notes(conn: &Connection, q: &ListQuery) -> rusqlite::Result<Vec<Note
         " ORDER BY pinned DESC, position DESC, updated_at DESC"
     });
 
+    notes_where(conn, &sql, params_from_iter(binds.iter()))
+}
+
+/// The notes whose ids `sql` selects, in its order, each loaded in full. Every list
+/// the UI reads goes through `load_note`, so a list and the note it opens can never
+/// disagree about what the note is.
+fn notes_where<P: Params>(conn: &Connection, sql: &str, params: P) -> rusqlite::Result<Vec<Note>> {
     let ids: Vec<String> = {
-        let mut stmt = conn.prepare(&sql)?;
-        let rows = stmt.query_map(params_from_iter(binds.iter()), |r| r.get::<_, String>(0))?;
+        let mut stmt = conn.prepare(sql)?;
+        let rows = stmt.query_map(params, |r| r.get::<_, String>(0))?;
         rows.collect::<rusqlite::Result<Vec<String>>>()?
     };
     ids.iter().map(|id| load_note(conn, id)).collect()
@@ -452,15 +459,14 @@ pub fn get_note(conn: &Connection, id: &str) -> rusqlite::Result<Note> {
 }
 
 pub fn reminders(conn: &Connection) -> rusqlite::Result<Vec<Note>> {
-    let ids: Vec<String> = {
-        let mut stmt =
-            // The owner's reminders: a note shared with us neither alerts us nor is ours
-            // to clear, the same as on the server.
-            conn.prepare("SELECT id FROM notes WHERE trashed = 0 AND remind_at IS NOT NULL AND permission = 'owner' ORDER BY remind_at ASC")?;
-        let rows = stmt.query_map([], |r| r.get::<_, String>(0))?;
-        rows.collect::<rusqlite::Result<Vec<String>>>()?
-    };
-    ids.iter().map(|id| load_note(conn, id)).collect()
+    // The owner's reminders: a note shared with us neither alerts us nor is ours to
+    // clear, the same as on the server.
+    notes_where(
+        conn,
+        "SELECT id FROM notes WHERE trashed = 0 AND remind_at IS NOT NULL AND permission = 'owner'
+          ORDER BY remind_at ASC",
+        [],
+    )
 }
 
 /// Reminders due at or before `now_ms`, soonest first, trash excluded.
@@ -501,35 +507,24 @@ pub fn due_reminders(conn: &Connection, now_ms: i64) -> rusqlite::Result<Vec<Due
 }
 
 pub fn titles(conn: &Connection) -> rusqlite::Result<Vec<TitleEntry>> {
-    // Names come from `load_note` so the palette and the card can never disagree
-    // about what a note is called. The command palette reads this; correctness
-    // beats one query per note at personal scale.
-    let ids: Vec<String> = {
-        let mut stmt = conn.prepare("SELECT id FROM notes WHERE trashed = 0")?;
-        let rows = stmt.query_map([], |r| r.get(0))?;
-        rows.collect::<rusqlite::Result<Vec<String>>>()?
-    };
-    ids.iter()
-        .map(|id| {
-            let note = load_note(conn, id)?;
-            Ok(TitleEntry {
-                id: note.id,
-                title: note.display_title,
-            })
+    // The command palette reads this; one query per note is fine at personal scale.
+    let notes = notes_where(conn, "SELECT id FROM notes WHERE trashed = 0", [])?;
+    Ok(notes
+        .into_iter()
+        .map(|note| TitleEntry {
+            id: note.id,
+            title: note.display_title,
         })
-        .collect()
+        .collect())
 }
 
 pub fn search(conn: &Connection, q: &str) -> rusqlite::Result<Vec<Note>> {
     let pat = format!("%{}%", escape_like(q));
-    let ids: Vec<String> = {
-        let mut stmt = conn.prepare(
-            "SELECT id FROM notes WHERE trashed = 0 AND body LIKE ?1 ESCAPE '\\' ORDER BY updated_at DESC",
-        )?;
-        let rows = stmt.query_map([&pat], |r| r.get::<_, String>(0))?;
-        rows.collect::<rusqlite::Result<Vec<String>>>()?
-    };
-    ids.iter().map(|id| load_note(conn, id)).collect()
+    notes_where(
+        conn,
+        "SELECT id FROM notes WHERE trashed = 0 AND body LIKE ?1 ESCAPE '\\' ORDER BY updated_at DESC",
+        [&pat],
+    )
 }
 
 // ---- notes: write -----------------------------------------------------------
@@ -1031,39 +1026,28 @@ pub fn restore_revision(conn: &Connection, id: &str, rev_id: &str) -> rusqlite::
 
 // ---- labels -----------------------------------------------------------------
 
+/// A label with how many live notes carry it; `label_row` reads it.
+const LABEL_SELECT: &str = "SELECT l.id, l.name, l.color,
+        (SELECT COUNT(*) FROM note_labels nl JOIN notes n ON n.id = nl.note_id
+         WHERE nl.label_id = l.id AND n.trashed = 0)
+     FROM labels l";
+
+fn label_row(r: &rusqlite::Row<'_>) -> rusqlite::Result<Label> {
+    Ok(Label {
+        id: r.get(0)?,
+        name: r.get(1)?,
+        color: r.get(2)?,
+        count: Some(r.get(3)?),
+    })
+}
+
 fn load_label(conn: &Connection, id: &str) -> rusqlite::Result<Label> {
-    conn.query_row(
-        "SELECT l.id, l.name, l.color,
-                (SELECT COUNT(*) FROM note_labels nl JOIN notes n ON n.id = nl.note_id
-                 WHERE nl.label_id = l.id AND n.trashed = 0)
-         FROM labels l WHERE l.id = ?1",
-        [id],
-        |r| {
-            Ok(Label {
-                id: r.get(0)?,
-                name: r.get(1)?,
-                color: r.get(2)?,
-                count: Some(r.get(3)?),
-            })
-        },
-    )
+    conn.query_row(&format!("{LABEL_SELECT} WHERE l.id = ?1"), [id], label_row)
 }
 
 pub fn list_labels(conn: &Connection) -> rusqlite::Result<Vec<Label>> {
-    let mut stmt = conn.prepare(
-        "SELECT l.id, l.name, l.color,
-                (SELECT COUNT(*) FROM note_labels nl JOIN notes n ON n.id = nl.note_id
-                 WHERE nl.label_id = l.id AND n.trashed = 0)
-         FROM labels l ORDER BY l.name COLLATE NOCASE",
-    )?;
-    let rows = stmt.query_map([], |r| {
-        Ok(Label {
-            id: r.get(0)?,
-            name: r.get(1)?,
-            color: r.get(2)?,
-            count: Some(r.get(3)?),
-        })
-    })?;
+    let mut stmt = conn.prepare(&format!("{LABEL_SELECT} ORDER BY l.name COLLATE NOCASE"))?;
+    let rows = stmt.query_map([], label_row)?;
     rows.collect()
 }
 
@@ -1170,19 +1154,25 @@ pub fn merge_labels(
 
 // ---- saved filters ----------------------------------------------------------
 
+const SAVED_FILTER_SELECT: &str = "SELECT id, name, params, position FROM saved_filters";
+
+/// A stored filter. Params that no longer parse read as no filter at all rather
+/// than failing the whole list.
+fn saved_filter_row(r: &rusqlite::Row<'_>) -> rusqlite::Result<SavedFilter> {
+    let params_str: String = r.get(2)?;
+    Ok(SavedFilter {
+        id: r.get(0)?,
+        name: r.get(1)?,
+        params: serde_json::from_str(&params_str).unwrap_or_else(|_| json!({})),
+        position: r.get(3)?,
+    })
+}
+
 pub fn list_saved_filters(conn: &Connection) -> rusqlite::Result<Vec<SavedFilter>> {
-    let mut stmt =
-        conn.prepare("SELECT id, name, params, position FROM saved_filters ORDER BY position ASC, name COLLATE NOCASE")?;
-    let rows = stmt.query_map([], |r| {
-        let params_str: String = r.get(2)?;
-        let params = serde_json::from_str(&params_str).unwrap_or_else(|_| serde_json::json!({}));
-        Ok(SavedFilter {
-            id: r.get(0)?,
-            name: r.get(1)?,
-            params,
-            position: r.get(3)?,
-        })
-    })?;
+    let mut stmt = conn.prepare(&format!(
+        "{SAVED_FILTER_SELECT} ORDER BY position ASC, name COLLATE NOCASE"
+    ))?;
+    let rows = stmt.query_map([], saved_filter_row)?;
     rows.collect()
 }
 
@@ -1225,19 +1215,9 @@ pub fn rename_saved_filter(
         params![name, id],
     )?;
     conn.query_row(
-        "SELECT id, name, params, position FROM saved_filters WHERE id = ?1",
+        &format!("{SAVED_FILTER_SELECT} WHERE id = ?1"),
         [id],
-        |r| {
-            let params_str: String = r.get(2)?;
-            let params =
-                serde_json::from_str(&params_str).unwrap_or_else(|_| serde_json::json!({}));
-            Ok(SavedFilter {
-                id: r.get(0)?,
-                name: r.get(1)?,
-                params,
-                position: r.get(3)?,
-            })
-        },
+        saved_filter_row,
     )
 }
 
diff --git a/core/src/sync/engine.rs b/core/src/sync/engine.rs
index 378577f..09eea35 100644
--- a/core/src/sync/engine.rs
+++ b/core/src/sync/engine.rs
@@ -67,7 +67,7 @@ pub async fn run_cycle(
         } else {
             state::SHARES
         };
-        let conn = db.0.lock().map_err(|e| e.to_string())?;
+        let conn = db.conn()?;
         if state::begin_shares(&conn, level).map_err(|e| e.to_string())? {
             log::info!("the server shares more of notes now; pulling everything once");
         }
@@ -91,7 +91,7 @@ pub async fn run_cycle(
     let retention = server.and_then(|s| s.trash_retention_days);
 
     let status = {
-        let conn = db.0.lock().map_err(|e| e.to_string())?;
+        let conn = db.conn()?;
         if let Some(days) = retention {
             state::set_server_retention(&conn, days as i64).map_err(|e| e.to_string())?;
         }
diff --git a/core/src/sync/pull.rs b/core/src/sync/pull.rs
index 4789a50..86d310f 100644
--- a/core/src/sync/pull.rs
+++ b/core/src/sync/pull.rs
@@ -79,7 +79,7 @@ async fn download_missing_blobs(
     token: &str,
 ) -> Result<(usize, usize), String> {
     let wanted = {
-        let conn = db.0.lock().map_err(|e| e.to_string())?;
+        let conn = db.conn()?;
         hashed_attachments(&conn).map_err(|e| e.to_string())?
     };
 
@@ -446,7 +446,7 @@ pub async fn run(
 
     loop {
         let since = {
-            let conn = db.0.lock().map_err(|e| e.to_string())?;
+            let conn = db.conn()?;
             state::read(&conn).map_err(|e| e.to_string())?.last_cursor
         };
 
@@ -463,7 +463,7 @@ pub async fn run(
 
         let has_more = page.has_more;
         let applied = {
-            let conn = db.0.lock().map_err(|e| e.to_string())?;
+            let conn = db.conn()?;
             apply_page(&conn, &page).map_err(|e| e.to_string())?
         };
         total.absorb(applied);
diff --git a/core/src/sync/push.rs b/core/src/sync/push.rs
index 3925629..c3e72ff 100644
--- a/core/src/sync/push.rs
+++ b/core/src/sync/push.rs
@@ -64,7 +64,7 @@ impl PushSummary {
 /// One entry in the `changes` array. Notes and labels share the envelope; serde skips
 /// the fields that don't apply, so the server sees exactly the shape docs/sync.md
 /// describes for each entity.
-#[derive(Debug, Serialize)]
+#[derive(Debug, Default, Serialize)]
 pub struct Change {
     pub entity: &'static str,
     pub id: String,
@@ -110,18 +110,7 @@ impl Change {
             id,
             op: "delete",
             edited_at,
-            body: None,
-            color: None,
-            pinned: None,
-            archived: None,
-            trashed: None,
-            remind_at: None,
-            recurrence: None,
-            position: None,
-            label_ids: None,
-            created_at: None,
-            name: None,
-            state_at: None,
+            ..Default::default()
         }
     }
 }
@@ -237,16 +226,7 @@ fn collect_labels(conn: &Connection, out: &mut Vec<Change>, limit: usize) -> rus
             name: Some(r.get(1)?),
             color: Some(r.get(2)?),
             edited_at: r.get(3)?,
-            body: None,
-            pinned: None,
-            archived: None,
-            trashed: None,
-            remind_at: None,
-            recurrence: None,
-            position: None,
-            label_ids: None,
-            created_at: None,
-            state_at: None,
+            ..Default::default()
         })
     })?;
     for row in rows {
@@ -342,17 +322,11 @@ fn note_change(conn: &Connection, id: &str, shared_state: bool) -> rusqlite::Res
             op: "upsert",
             edited_at: row.updated_at,
             body: (row.permission == "edit").then_some(row.body),
-            color: None,
             pinned: own.then_some(row.pinned),
             archived: own.then_some(row.archived),
-            trashed: None,
-            remind_at: None,
-            recurrence: None,
             position: own.then_some(row.position),
-            label_ids: None,
-            created_at: None,
-            name: None,
             state_at,
+            ..Default::default()
         });
     }
 
@@ -374,8 +348,6 @@ fn note_change(conn: &Connection, id: &str, shared_state: bool) -> rusqlite::Res
         // server's last-write-wins comparison runs against.
         edited_at: row.updated_at,
         body: Some(row.body),
-        // A note has no colour to send. See the field on `Change`.
-        color: None,
         pinned: Some(row.pinned),
         archived: Some(row.archived),
         trashed: Some(row.trashed),
@@ -384,8 +356,7 @@ fn note_change(conn: &Connection, id: &str, shared_state: bool) -> rusqlite::Res
         position: Some(row.position),
         label_ids: Some(label_ids),
         created_at: Some(row.created_at),
-        name: None,
-        state_at: None,
+        ..Default::default()
     })
 }
 
@@ -610,7 +581,7 @@ async fn upload_pending(
     token: &str,
 ) -> Result<PushSummary, String> {
     let wanted = {
-        let conn = db.0.lock().map_err(|e| e.to_string())?;
+        let conn = db.conn()?;
         pending_uploads(&conn).map_err(|e| e.to_string())?
     };
     let mut summary = PushSummary::default();
@@ -636,7 +607,7 @@ async fn upload_pending(
             )),
         };
         {
-            let conn = db.0.lock().map_err(|e| e.to_string())?;
+            let conn = db.conn()?;
             settle_upload(&conn, &upload.id, &result).map_err(|e| e.to_string())?;
         }
         match result {
@@ -669,7 +640,7 @@ pub async fn run(
 
     loop {
         let batch = {
-            let conn = db.0.lock().map_err(|e| e.to_string())?;
+            let conn = db.conn()?;
             collect(&conn, BATCH, accepts).map_err(|e| e.to_string())?
         };
         if batch.is_empty() {
@@ -680,7 +651,7 @@ pub async fn run(
         let results = parse_results(&raw)?;
 
         let applied = {
-            let conn = db.0.lock().map_err(|e| e.to_string())?;
+            let conn = db.conn()?;
             apply_results(&conn, &batch, &results).map_err(|e| e.to_string())?
         };
         // Everything rejected clears nothing, so the same batch would be collected
diff --git a/core/src/sync/sharing.rs b/core/src/sync/sharing.rs
index 8271e73..301aea5 100644
--- a/core/src/sync/sharing.rs
+++ b/core/src/sync/sharing.rs
@@ -18,7 +18,7 @@ pub const NEEDS_SERVER: &str =
     "Sharing is between people on a server. Link this device to one in Sync to share notes.";
 
 fn link(db: &Db) -> Result<(String, String), String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     let link = state::read(&conn).map_err(|e| e.to_string())?;
     match (link.server_url, link.device_token) {
         (Some(url), Some(token)) => Ok((url, token)),
@@ -29,7 +29,7 @@ fn link(db: &Db) -> Result<(String, String), String> {
 /// Set the local note's `shared` flag from the server's list of its shares. Not a
 /// local edit, so it leaves `dirty` and `updated_at` alone.
 fn mark_shared(db: &Db, note_id: &str, shares: &[NoteShare]) -> Result<(), String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     conn.execute(
         "UPDATE notes SET shared = ?2 WHERE id = ?1 AND permission = 'owner'",
         params![note_id, !shares.is_empty()],
diff --git a/desktop/src-tauri/src/autosync.rs b/desktop/src-tauri/src/autosync.rs
index 8539da7..64a6c11 100644
--- a/desktop/src-tauri/src/autosync.rs
+++ b/desktop/src-tauri/src/autosync.rs
@@ -175,7 +175,7 @@ fn backoff(failures: u32) -> Duration {
 
 /// The server URL and token, or None when this device isn't linked.
 fn credentials(db: &Db) -> Result<Option<(String, String)>, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     let current = state::read(&conn).map_err(|e| e.to_string())?;
     Ok(current.server_url.zip(current.device_token))
 }
@@ -183,7 +183,7 @@ fn credentials(db: &Db) -> Result<Option<(String, String)>, String> {
 /// What is waiting to be sent, as [`push::pending_fingerprint`] sees it. A store
 /// that can't be read reads as nothing pending; the periodic cycle still runs.
 fn pending(db: &Db) -> Option<String> {
-    let conn = db.0.lock().ok()?;
+    let conn = db.conn().ok()?;
     push::pending_fingerprint(&conn).ok().flatten()
 }
 
diff --git a/desktop/src-tauri/src/capture.rs b/desktop/src-tauri/src/capture.rs
index 5cd7fc7..f3cc9ab 100644
--- a/desktop/src-tauri/src/capture.rs
+++ b/desktop/src-tauri/src/capture.rs
@@ -60,7 +60,7 @@ pub struct CaptureShortcut {
 }
 
 fn stored(db: &Db) -> Result<String, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     Ok(store::pref(&conn, SHORTCUT_PREF)
         .map_err(|e| e.to_string())?
         .unwrap_or_default())
@@ -187,7 +187,7 @@ pub fn capture_shortcut_set(
 ) -> Result<CaptureShortcut, String> {
     let wanted = shortcut.trim().to_string();
     register(&app, &wanted)?;
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::set_pref(&conn, SHORTCUT_PREF, &wanted).map_err(|e| e.to_string())?;
     log::info!(
         "quick capture shortcut {}",
diff --git a/desktop/src-tauri/src/commands/local.rs b/desktop/src-tauri/src/commands/local.rs
index 5c86919..cdffe69 100644
--- a/desktop/src-tauri/src/commands/local.rs
+++ b/desktop/src-tauri/src/commands/local.rs
@@ -54,37 +54,37 @@ pub fn auth_me() -> User {
 
 #[tauri::command]
 pub fn notes_list(query: ListQuery, db: State<'_, Db>) -> Result<Vec<Note>, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::list_notes(&conn, &query).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_get(id: String, db: State<'_, Db>) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::get_note(&conn, &id).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_create(input: NoteCreateInput, db: State<'_, Db>) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::create_note(&conn, &input).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_update(id: String, changes: Value, db: State<'_, Db>) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::update_note(&conn, &id, &changes).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_complete_reminder(id: String, db: State<'_, Db>) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::complete_reminder(&conn, &id).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_snooze_reminder(id: String, minutes: i64, db: State<'_, Db>) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::snooze_reminder(&conn, &id, minutes).map_err(|e| e.to_string())
 }
 
@@ -94,7 +94,7 @@ pub fn notes_set_labels(
     label_ids: Vec<String>,
     db: State<'_, Db>,
 ) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::set_labels(&conn, &id, &label_ids).map_err(|e| e.to_string())
 }
 
@@ -105,7 +105,7 @@ pub fn notes_update_item(
     changes: Value,
     db: State<'_, Db>,
 ) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::update_item(&conn, &id, &item_id, &changes).map_err(|e| e.to_string())
 }
 
@@ -134,7 +134,7 @@ pub async fn notes_add_attachment(
     let note_id = header("x-note-id");
     let filename = blobs::urldecode(header("x-filename"));
     let mime = header("x-mime");
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::add_attachment(&conn, &blobs, note_id, &filename, mime, bytes)
 }
 
@@ -152,7 +152,7 @@ pub async fn notes_export(
 ) -> Result<String, String> {
     use tauri::Manager;
     let bytes = {
-        let conn = db.0.lock().map_err(|e| e.to_string())?;
+        let conn = db.conn()?;
         portable::export_zip(&conn, &blobs)?
     };
     let dir = app
@@ -188,7 +188,7 @@ pub async fn notes_import(
     let tauri::ipc::InvokeBody::Raw(bytes) = request.body() else {
         return Err("The file's contents didn't arrive.".to_string());
     };
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     portable::import_zip(&conn, &blobs, bytes)
 }
 
@@ -198,7 +198,7 @@ pub fn notes_delete_attachment(
     att_id: String,
     db: State<'_, Db>,
 ) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::delete_attachment(&conn, &id, &att_id).map_err(|e| e.to_string())
 }
 
@@ -208,37 +208,37 @@ pub fn notes_delete_preview(
     preview_id: String,
     db: State<'_, Db>,
 ) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::delete_preview(&conn, &id, &preview_id).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_reorder(ordered_ids: Vec<String>, db: State<'_, Db>) -> Result<(), String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::reorder(&conn, &ordered_ids).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_trash(id: String, db: State<'_, Db>) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::trash(&conn, &id).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_restore(id: String, db: State<'_, Db>) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::restore(&conn, &id).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_delete_forever(id: String, db: State<'_, Db>) -> Result<(), String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::delete_forever(&conn, &id).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_revisions(id: String, db: State<'_, Db>) -> Result<Vec<NoteRevision>, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::revisions(&conn, &id).map_err(|e| e.to_string())
 }
 
@@ -248,61 +248,61 @@ pub fn notes_restore_revision(
     rev_id: String,
     db: State<'_, Db>,
 ) -> Result<Note, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::restore_revision(&conn, &id, &rev_id).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_reminders(db: State<'_, Db>) -> Result<Vec<Note>, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::reminders(&conn).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn notes_titles(db: State<'_, Db>) -> Result<Vec<TitleEntry>, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::titles(&conn).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn labels_list(db: State<'_, Db>) -> Result<Vec<Label>, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::list_labels(&conn).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn labels_create(name: String, db: State<'_, Db>) -> Result<Label, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::create_label(&conn, &name).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn labels_rename(id: String, name: String, db: State<'_, Db>) -> Result<Label, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::rename_label(&conn, &id, &name).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn labels_set_color(id: String, color: String, db: State<'_, Db>) -> Result<Label, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::set_label_color(&conn, &id, &color).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn labels_remove(id: String, db: State<'_, Db>) -> Result<(), String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::remove_label(&conn, &id).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn labels_merge(source_id: String, into: String, db: State<'_, Db>) -> Result<Label, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::merge_labels(&conn, &source_id, &into).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn saved_filters_list(db: State<'_, Db>) -> Result<Vec<SavedFilter>, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::list_saved_filters(&conn).map_err(|e| e.to_string())
 }
 
@@ -312,13 +312,13 @@ pub fn saved_filters_create(
     params: Value,
     db: State<'_, Db>,
 ) -> Result<SavedFilter, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::create_saved_filter(&conn, &name, &params).map_err(|e| e.to_string())
 }
 
 #[tauri::command]
 pub fn saved_filters_remove(id: String, db: State<'_, Db>) -> Result<(), String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::remove_saved_filter(&conn, &id).map_err(|e| e.to_string())
 }
 
@@ -328,6 +328,6 @@ pub fn saved_filters_rename(
     name: String,
     db: State<'_, Db>,
 ) -> Result<SavedFilter, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::rename_saved_filter(&conn, &id, &name).map_err(|e| e.to_string())
 }
diff --git a/desktop/src-tauri/src/commands/sync.rs b/desktop/src-tauri/src/commands/sync.rs
index d1a2419..7c38f26 100644
--- a/desktop/src-tauri/src/commands/sync.rs
+++ b/desktop/src-tauri/src/commands/sync.rs
@@ -96,7 +96,7 @@ pub async fn sync_link(input: LinkInput, db: State<'_, Db>) -> Result<LinkResult
     //    isn't Send so it cannot be held across an await, and holding the store
     //    locked for a network round-trip would freeze every note operation in the UI.
     let status = {
-        let conn = db.0.lock().map_err(|e| e.to_string())?;
+        let conn = db.conn()?;
         state::set_link(&conn, &base_url, &token).map_err(|e| e.to_string())?;
         // Adopt the server's trash-retention window immediately, so the Trash view
         // stops counting down against this device's offline default the moment it's
@@ -135,7 +135,7 @@ pub async fn sync_unlink(db: State<'_, Db>) -> Result<UnlinkResult, String> {
     // holding the store across a round-trip would freeze every note operation in
     // the UI.
     let link = {
-        let conn = db.0.lock().map_err(|e| e.to_string())?;
+        let conn = db.conn()?;
         let current = state::read(&conn).map_err(|e| e.to_string())?;
         current.server_url.zip(current.device_token)
     };
@@ -144,7 +144,7 @@ pub async fn sync_unlink(db: State<'_, Db>) -> Result<UnlinkResult, String> {
         None => client::RevokeOutcome::Skipped,
     };
 
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     state::clear_link(&conn).map_err(|e| e.to_string())?;
     log::info!("unlinked from server (server-side token: {revoked:?})");
     Ok(UnlinkResult {
@@ -155,7 +155,7 @@ pub async fn sync_unlink(db: State<'_, Db>) -> Result<UnlinkResult, String> {
 
 #[tauri::command]
 pub fn sync_status(db: State<'_, Db>) -> Result<state::Status, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     state::status(&conn).map_err(|e| e.to_string())
 }
 
@@ -183,7 +183,7 @@ pub fn sync_last(autosync: State<'_, AutoSync>) -> Option<LastCycle> {
 /// changes" state without running a sync to find out.
 #[tauri::command]
 pub fn sync_has_pending(db: State<'_, Db>) -> Result<bool, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     push::has_pending(&conn).map_err(|e| e.to_string())
 }
 
diff --git a/desktop/src-tauri/src/reminders.rs b/desktop/src-tauri/src/reminders.rs
index 02f644f..b40352b 100644
--- a/desktop/src-tauri/src/reminders.rs
+++ b/desktop/src-tauri/src/reminders.rs
@@ -69,7 +69,7 @@ fn worker(app: AppHandle) {
 
 fn due(app: &AppHandle, now: i64) -> Result<Vec<DueReminder>, String> {
     let db = app.state::<Db>();
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::due_reminders(&conn, now).map_err(|e| e.to_string())
 }
 
diff --git a/desktop/src-tauri/src/update.rs b/desktop/src-tauri/src/update.rs
index 10d3bc5..61f8239 100644
--- a/desktop/src-tauri/src/update.rs
+++ b/desktop/src-tauri/src/update.rs
@@ -180,7 +180,7 @@ pub fn adopt_installer_channel(db: &Db, data_dir: &Path) {
 /// Apply `channel` unless we already applied this same marker value. Returns whether
 /// anything changed.
 fn adopt(db: &Db, channel: Channel) -> Result<bool, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     let adopted = store::pref(&conn, CHANNEL_SEED_PREF).map_err(|e| e.to_string())?;
     // Already acted on this marker — whatever the pref says now is the user's own
     // choice, and re-applying would quietly undo it.
@@ -193,7 +193,7 @@ fn adopt(db: &Db, channel: Channel) -> Result<bool, String> {
 }
 
 fn read_channel(db: &State<'_, Db>) -> Result<Channel, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     let raw = store::pref(&conn, CHANNEL_PREF).map_err(|e| e.to_string())?;
     Ok(raw
         .as_deref()
@@ -208,7 +208,7 @@ pub fn update_channel_get(db: State<'_, Db>) -> Result<Channel, String> {
 
 #[tauri::command]
 pub fn update_channel_set(channel: Channel, db: State<'_, Db>) -> Result<Channel, String> {
-    let conn = db.0.lock().map_err(|e| e.to_string())?;
+    let conn = db.conn()?;
     store::set_pref(&conn, CHANNEL_PREF, channel.as_str()).map_err(|e| e.to_string())?;
     log::info!("update channel set to {}", channel.as_str());
     Ok(channel)