fix: more production crashes (View Transition noise, book-dir race, stats transaction) (#4962)

* fix(sentry): drop more benign View Transition rejections

Broaden is_ignored_browser_error to also drop "Transition was skipped"
(navigation superseded, READEST-F) and "aborted because of invalid state"
(READEST-G), matched case-insensitively alongside the existing hidden-tab case.
These are expected browser behavior — the navigation completes, only the
animation is skipped/aborted. A transition timeout stays visible (real perf
signal, handled separately).

Fixes READEST-F
Fixes READEST-G

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(library): create the book directory idempotently

Importing a book did a check-then-create with a non-recursive createDir. Two
concurrent imports of the same book both pass the exists check, then the second
create fails — on Windows with "Cannot create a file when that file already
exists" (Sentry READEST-H). Use a recursive create (create_dir_all), a no-op
when the directory already exists.

Fixes READEST-H

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(stats): serialize applyRemoteEvents to avoid nested transactions

The statistics connection is shared across ReadingStatsTracker instances (split
view). applyRemoteEvents runs a manual BEGIN/COMMIT that the per-op native
connection lock does not make atomic, so two concurrent pulls opened a BEGIN
inside a BEGIN ("cannot start a transaction within a transaction", Sentry
READEST-N). Serialize applyRemoteEvents against itself with a small promise
mutex. Adds a regression test that fails without the guard.

Fixes READEST-N

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/readest-app/src-tauri/src/sentry_config.rs

@@ -76,13 +76,18 @@ pub fn android_version_from_uname(release: &str) -> Option<String> {
     }
 }
 
-/// A known-benign browser error that is expected behavior, not an app bug, and
+/// Known-benign browser errors that are expected behavior, not app bugs, and
-/// only adds noise to crash reporting: the View Transition API skips a
+/// only add noise to crash reporting: the View Transition API skips a transition
-/// transition when the tab is hidden. Matched on the exception value so it is
+/// when the tab is hidden or the navigation is superseded, and aborts it when the
-/// dropped in `before_send`. NOTE: a transition *timeout* abort is deliberately
+/// document is in an invalid state. These arrive as unhandled rejections while
-/// NOT ignored — a slow DOM update can signal a real performance problem.
+/// the navigation itself still completes. Matched (case-insensitively) on the
+/// exception value so they are dropped in `before_send`. NOTE: a transition
+/// *timeout* abort is deliberately NOT ignored — a slow DOM update can signal a
+/// real performance problem.
 pub fn is_ignored_browser_error(value: &str) -> bool {
-    value.contains("View transition was skipped because document visibility state is hidden")
+    let value = value.to_lowercase();
+    value.contains("transition was skipped")
+        || value.contains("transition was aborted because of invalid state")
 }
 
 /// The WebView (engine, major-version), set once at startup when the app reports
@@ -216,10 +221,19 @@ mod tests {
     }
 
     #[test]
-    fn ignores_benign_hidden_view_transition_error() {
+    fn ignores_benign_view_transition_errors() {
+        // Skipped because the tab is hidden (READEST-7).
         assert!(is_ignored_browser_error(
             "InvalidStateError: View transition was skipped because document visibility state is hidden."
         ));
+        // Skipped because the navigation was superseded (READEST-F).
+        assert!(is_ignored_browser_error(
+            "AbortError: Transition was skipped"
+        ));
+        // Aborted because the document was in an invalid state (READEST-G).
+        assert!(is_ignored_browser_error(
+            "InvalidStateError: Transition was aborted because of invalid state"
+        ));
     }
 
     #[test]

apps/readest-app/src/__tests__/statistics/statisticsDb.test.ts

@@ -103,6 +103,22 @@ describe('StatisticsDb', () => {
     expect(book!.total_read_time).toBe(8);
   });
 
+  it('serializes concurrent applyRemoteEvents without nesting transactions (READEST-N)', async () => {
+    // Two pulls racing on the shared connection (split-view trackers) must not
+    // open a BEGIN inside a BEGIN ("cannot start a transaction within a transaction").
+    const a = stats.applyRemoteEvents(
+      [{ bookMd5: 'ra', title: 'RA', authors: '' }],
+      [{ bookMd5: 'ra', page: 1, startTime: 400, duration: 3, totalPages: 10 }],
+    );
+    const b = stats.applyRemoteEvents(
+      [{ bookMd5: 'rb', title: 'RB', authors: '' }],
+      [{ bookMd5: 'rb', page: 1, startTime: 401, duration: 4, totalPages: 10 }],
+    );
+    await expect(Promise.all([a, b])).resolves.toBeDefined();
+    expect((await stats.getBookByMd5('ra'))!.total_read_time).toBe(3);
+    expect((await stats.getBookByMd5('rb'))!.total_read_time).toBe(4);
+  });
+
   it('reads and writes sync cursors', async () => {
     expect(await stats.getCursor('push')).toBe(0);
     await stats.setCursor('push', 1234);

apps/readest-app/src/services/bookService.ts

@@ -537,9 +537,12 @@ export async function importBook(
       existingBook.downloadedAt = Date.now();
     }
 
-    if (!(await fs.exists(getDir(book), 'Books'))) {
+    // Idempotent create (recursive): a plain createDir defaults to
-      await fs.createDir(getDir(book), 'Books');
+    // non-recursive and throws if the dir already exists, and the check-then-
-    }
+    // create above races two concurrent imports of the same book — on Windows
+    // the loser fails with "Cannot create a file when that file already exists"
+    // (Sentry READEST-H). create_dir_all is a no-op when the dir exists.
+    await fs.createDir(getDir(book), 'Books', true);
     const bookFilename = getLocalBookFilename(book);
     const willWriteBookFile =
       saveBook &&

apps/readest-app/src/services/statistics/statisticsDb.ts

@@ -43,6 +43,9 @@ function bindLifecycle(): void {
  * leaves this class.
  */
 export class StatisticsDb {
+  // Serializes applyRemoteEvents so two concurrent pulls can't nest BEGINs.
+  private applyRemoteLock: Promise<void> = Promise.resolve();
+
   private constructor(private readonly db: DatabaseService) {}
 
   /** Production entry point — opens + migrates statistics.db (per-tab singleton). */
@@ -187,29 +190,42 @@ export class StatisticsDb {
 
   async applyRemoteEvents(books: StatBook[], events: PageStatEvent[]): Promise<void> {
     if (books.length === 0 && events.length === 0) return;
-    // One transaction for the whole pulled batch: a single commit instead of
+    // Serialize against other pulls: the statistics connection is shared across
-    // O(rows) fsyncs, and the apply is atomic (a failed pull leaves no partial
+    // ReadingStatsTracker instances (split view), and a second concurrent pull
-    // state). Critical when a fresh device backfills tens of thousands of rows.
+    // would open a BEGIN inside this one's still-open BEGIN ("cannot start a
-    await this.db.execute('BEGIN');
+    // transaction within a transaction", Sentry READEST-N). The per-op native
+    // lock can't make this multi-statement transaction atomic on its own.
+    const prev = this.applyRemoteLock;
+    let release!: () => void;
+    this.applyRemoteLock = new Promise<void>((resolve) => (release = resolve));
+    await prev;
     try {
-      const idByMd5 = new Map<string, number>();
+      // One transaction for the whole pulled batch: a single commit instead of
-      for (const b of books) idByMd5.set(b.bookMd5, await this.upsertBook(b));
+      // O(rows) fsyncs, and the apply is atomic (a failed pull leaves no partial
-      // Books referenced only by events (no metadata record) get a placeholder row.
+      // state). Critical when a fresh device backfills tens of thousands of rows.
-      const touched = new Set<number>();
+      await this.db.execute('BEGIN');
-      for (const e of events) {
+      try {
-        let id = idByMd5.get(e.bookMd5);
+        const idByMd5 = new Map<string, number>();
-        if (id === undefined) {
+        for (const b of books) idByMd5.set(b.bookMd5, await this.upsertBook(b));
-          id = await this.ensureBookId(e.bookMd5);
+        // Books referenced only by events (no metadata record) get a placeholder row.
-          idByMd5.set(e.bookMd5, id);
+        const touched = new Set<number>();
+        for (const e of events) {
+          let id = idByMd5.get(e.bookMd5);
+          if (id === undefined) {
+            id = await this.ensureBookId(e.bookMd5);
+            idByMd5.set(e.bookMd5, id);
+          }
+          await this.insertPageEvent(id, e);
+          touched.add(id);
         }
-        await this.insertPageEvent(id, e);
+        for (const id of touched) await this.recomputeBookTotals(id);
-        touched.add(id);
+        await this.db.execute('COMMIT');
+      } catch (err) {
+        await this.db.execute('ROLLBACK');
+        throw err;
       }
-      for (const id of touched) await this.recomputeBookTotals(id);
+    } finally {
-      await this.db.execute('COMMIT');
+      release();
-    } catch (err) {
-      await this.db.execute('ROLLBACK');
-      throw err;
     }
   }