fix(server): auto-recover from corrupted SQLite database on startup

apps/server/src/persistence/Layers/Sqlite.ts

@@ -1,9 +1,31 @@
 import { Effect, Layer, FileSystem, Path } from "effect";
 import * as SqlClient from "effect/unstable/sql/SqlClient";
+import { openSync, readSync, closeSync } from "node:fs";
 
 import { runMigrations } from "../Migrations.ts";
 import { ServerConfig } from "../../config.ts";
 
+// First 16 bytes of every valid SQLite database file
+const SQLITE_MAGIC = "SQLite format 3\0";
+
+/** Check whether the file at `dbPath` starts with the SQLite magic header. */
+const isSqliteFileValid = (dbPath: string): Effect.Effect<boolean> =>
+  Effect.sync(() => {
+    try {
+      const fd = openSync(dbPath, "r");
+      try {
+        const buf = Buffer.alloc(16);
+        const bytesRead = readSync(fd, buf, 0, 16, 0);
+        if (bytesRead < 16) return false;
+        return buf.toString("ascii", 0, 16) === SQLITE_MAGIC;
+      } finally {
+        closeSync(fd);
+      }
+    } catch {
+      return false;
+    }
+  });
+
 type RuntimeSqliteLayerConfig = {
   readonly filename: string;
 };
@@ -41,6 +63,27 @@ export const makeSqlitePersistenceLive = (dbPath: string) =>
     const path = yield* Path.Path;
     yield* fs.makeDirectory(path.dirname(dbPath), { recursive: true });
 
+    // Detect and recover from a corrupted database file.
+    // A valid SQLite file must start with "SQLite format 3\0".
+    // If the header is invalid, back up the corrupted file and let
+    // a fresh database be created so the app can start.
+    const fileExists = yield* fs.exists(dbPath);
+    if (fileExists) {
+      const valid = yield* isSqliteFileValid(dbPath);
+      if (!valid) {
+        const backupPath = `${dbPath}.corrupted.${Date.now()}`;
+        yield* Effect.logWarning(
+          `Corrupted database detected at ${dbPath}. ` +
+            `Backing up to ${backupPath} and creating a fresh database. ` +
+            `Session history will be reset.`,
+        );
+        yield* fs.rename(dbPath, backupPath);
+        // Remove stale WAL/SHM journal files from the corrupted database
+        yield* fs.remove(`${dbPath}-wal`).pipe(Effect.ignore);
+        yield* fs.remove(`${dbPath}-shm`).pipe(Effect.ignore);
+      }
+    }
+
     return Layer.provideMerge(setup, makeRuntimeSqliteLayer({ filename: dbPath }));
   }).pipe(Layer.unwrap);
 

apps/server/src/persistence/NodeSqliteClient.ts

@@ -86,7 +86,10 @@ const makeWithDatabase = (
 
     const makeConnection = Effect.gen(function* () {
       const scope = yield* Effect.scope;
-      const db = openDatabase();
+      const db = yield* Effect.try({
+        try: () => openDatabase(),
+        catch: (cause) => new SqlError({ cause, message: "Failed to open database" }),
+      }).pipe(Effect.orDie);
       yield* Scope.addFinalizer(
         scope,
         Effect.sync(() => db.close()),