Handle baseline migration for databases previously set up with db:push

When switching from db:push to db:migrate on an existing database,
the migration table is empty so Drizzle tries to re-run all migrations,
failing with "relation already exists".

Detect this case (tables exist but no migration history) and seed the
__drizzle_migrations tracking table with all current migrations so
Drizzle treats them as already applied. Future migrations run normally.

https://claude.ai/code/session_012sqEgNQpx676isepeoX4Mi

src/server/db/migrate.ts

@@ -6,6 +6,10 @@
  * This applies any pending migrations from the drizzle/ directory to the
  * database specified by DATABASE_URL. It is safe to run multiple times —
  * Drizzle tracks applied migrations in the __drizzle_migrations table.
+ *
+ * If the database was previously set up via `db:push` (no migration history),
+ * this script will baseline it: seed the migration history without re-running
+ * the SQL, so only future migrations are applied.
  */
 import * as dotenv from "dotenv";
 
@@ -17,6 +21,8 @@ import { Pool } from "pg";
 import { drizzle } from "drizzle-orm/node-postgres";
 import { migrate } from "drizzle-orm/node-postgres/migrator";
 import path from "path";
+import fs from "fs";
+import crypto from "crypto";
 import { fileURLToPath } from "url";
 
 const databaseUrl = process.env.DATABASE_URL;
@@ -36,9 +42,80 @@ const pool = new Pool({
 
 const db = drizzle(pool);
 
+/**
+ * Baseline: if the DB has existing tables but no migration history, seed the
+ * __drizzle_migrations table so Drizzle won't try to re-run already-applied SQL.
+ */
+async function baselineIfNeeded(client: Pool) {
+  // Check if migration tracking table exists and has entries
+  const { rows: migRows } = await client.query<{ count: string }>(`
+    SELECT COUNT(*)::text AS count
+    FROM information_schema.tables
+    WHERE table_schema = 'drizzle'
+      AND table_name = '__drizzle_migrations'
+  `);
+  const hasMigrationsTable = parseInt(migRows[0]?.count ?? "0") > 0;
+
+  if (hasMigrationsTable) {
+    const { rows: entryRows } = await client.query<{ count: string }>(
+      `SELECT COUNT(*)::text AS count FROM drizzle.__drizzle_migrations`
+    );
+    if (parseInt(entryRows[0]?.count ?? "0") > 0) {
+      // Migration history exists — normal flow
+      return;
+    }
+  }
+
+  // No migration history. Check if the DB already has our tables (was db:push'd).
+  const { rows: tableRows } = await client.query<{ count: string }>(`
+    SELECT COUNT(*)::text AS count
+    FROM information_schema.tables
+    WHERE table_schema = 'public'
+      AND table_name = 'beenvoice_account'
+  `);
+  const dbAlreadyExists = parseInt(tableRows[0]?.count ?? "0") > 0;
+
+  if (!dbAlreadyExists) {
+    // Fresh database — let migrate() run normally
+    return;
+  }
+
+  console.log("[migrate] Existing database detected without migration history — baselining...");
+
+  // Create the drizzle schema + migrations table if needed
+  await client.query(`CREATE SCHEMA IF NOT EXISTS drizzle`);
+  await client.query(`
+    CREATE TABLE IF NOT EXISTS drizzle.__drizzle_migrations (
+      id SERIAL PRIMARY KEY,
+      hash text NOT NULL,
+      created_at bigint
+    )
+  `);
+
+  // Read the journal and seed a record for every migration file
+  const journal = JSON.parse(
+    fs.readFileSync(path.join(migrationsFolder, "meta/_journal.json"), "utf8")
+  ) as { entries: { idx: number; tag: string; when: number }[] };
+
+  for (const entry of journal.entries) {
+    const sqlPath = path.join(migrationsFolder, `${entry.tag}.sql`);
+    const sql = fs.readFileSync(sqlPath, "utf8");
+    const hash = crypto.createHash("sha256").update(sql).digest("hex");
+
+    await client.query(
+      `INSERT INTO drizzle.__drizzle_migrations (hash, created_at) VALUES ($1, $2)`,
+      [hash, entry.when]
+    );
+    console.log(`[migrate] Baselined: ${entry.tag}`);
+  }
+
+  console.log("[migrate] Baseline complete — future migrations will apply normally");
+}
+
 console.log("[migrate] Running migrations from", migrationsFolder);
 
 try {
+  await baselineIfNeeded(pool);
   await migrate(db, { migrationsFolder });
   console.log("[migrate] All migrations applied successfully");
 } catch (err) {