Harden embedded postgres adoption on startup

packages/db/src/migration-runtime.ts

@@ -1,8 +1,7 @@
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { createServer } from "node:net";
 import path from "node:path";
-import postgres from "postgres";
-import { ensurePostgresDatabase } from "./client.js";
+import { ensurePostgresDatabase, getPostgresDataDirectory } from "./client.js";
 import { resolveDatabaseTarget } from "./runtime-config.js";
 
 type EmbeddedPostgresInstance = {
@@ -99,25 +98,6 @@ async function loadEmbeddedPostgresCtor(): Promise<EmbeddedPostgresCtor> {
   }
 }
 
-async function matchesEmbeddedDataDir(
-  adminConnectionString: string,
-  expectedDataDir: string,
-): Promise<boolean> {
-  const sql = postgres(adminConnectionString, { max: 1, onnotice: () => {} });
-  try {
-    const rows = await sql<{ data_directory: string | null }[]>`
-      SELECT current_setting('data_directory', true) AS data_directory
-    `;
-    const actual = rows[0]?.data_directory;
-    if (typeof actual !== "string" || actual.length === 0) return false;
-    return path.resolve(actual) === path.resolve(expectedDataDir);
-  } catch {
-    return false;
-  } finally {
-    await sql.end();
-  }
-}
-
 async function ensureEmbeddedPostgresConnection(
   dataDir: string,
   preferredPort: number,
@@ -132,7 +112,10 @@ async function ensureEmbeddedPostgresConnection(
 
   if (!runningPid && existsSync(pgVersionFile)) {
     try {
-      const matchesDataDir = await matchesEmbeddedDataDir(preferredAdminConnectionString, dataDir);
+      const actualDataDir = await getPostgresDataDirectory(preferredAdminConnectionString);
+      const matchesDataDir =
+        typeof actualDataDir === "string" &&
+        path.resolve(actualDataDir) === path.resolve(dataDir);
       if (!matchesDataDir) {
         throw new Error("reachable postgres does not use the expected embedded data directory");
       }