fix(db): handle camelCase postgres metadata keys in migration schema detection (#8092)

packages/better-auth/src/db/get-migration-schema.test.ts

@@ -1,4 +1,5 @@
 import type { BetterAuthOptions } from "@better-auth/core";
+import { CamelCasePlugin, Kysely, PostgresDialect } from "kysely";
 import { Pool } from "pg";
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
 import { betterAuth } from "../auth/full";
@@ -33,6 +34,10 @@ describe.runIf(isPostgresAvailable)(
 		const customSchemaPool = new Pool({
 			connectionString: `${CONNECTION_STRING}?options=-c search_path=${customSchema}`,
 		});
+		const customSchemaKysely = new Kysely({
+			dialect: new PostgresDialect({ pool: customSchemaPool }),
+			plugins: [new CamelCasePlugin()],
+		});
 
 		beforeAll(async () => {
 			// Setup: Create custom schema and a table in public schema
@@ -84,6 +89,54 @@ describe.runIf(isPostgresAvailable)(
 			expect(userTableCreated?.fields).toHaveProperty("emailVerified");
 		});
 
+		/**
+		 * @see https://github.com/better-auth/better-auth/issues/7926
+		 */
+		it("should detect custom schema with CamelCasePlugin enabled", async () => {
+			// Create a user table in the custom schema so it should be detected as existing
+			await customSchemaPool.query(`
+				CREATE TABLE IF NOT EXISTS ${customSchema}.user (
+					id TEXT PRIMARY KEY NOT NULL,
+					email TEXT NOT NULL,
+					name TEXT NOT NULL,
+					"emailVerified" BOOLEAN NOT NULL,
+					image TEXT,
+					"createdAt" TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP NOT NULL,
+					"updatedAt" TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP NOT NULL
+				);
+			`);
+
+			try {
+				const config: BetterAuthOptions = {
+					database: {
+						db: customSchemaKysely,
+						type: "postgres",
+					},
+					emailAndPassword: {
+						enabled: true,
+					},
+				};
+
+				const { toBeCreated, toBeAdded } = await getMigrations(config);
+
+				// user table exists in custom schema, so it should NOT be in toBeCreated
+				const userTableCreated = toBeCreated.find((t) => t.table === "user");
+				const userTableToBeAdded = toBeAdded.find((t) => t.table === "user");
+
+				expect(userTableCreated).toBeUndefined();
+				expect(userTableToBeAdded).toBeUndefined();
+
+				// Other tables should still need to be created
+				const sessionTable = toBeCreated.find((t) => t.table === "session");
+				expect(sessionTable).toBeDefined();
+			} finally {
+				// Cleanup: drop the user table so subsequent tests are not affected
+				await customSchemaPool.query(
+					`DROP TABLE IF EXISTS ${customSchema}.user CASCADE`,
+				);
+			}
+		});
+
 		it("should not be affected by tables in public schema when using custom schema", async () => {
 			// Even though there's a 'user' table in public schema,
 			// when we use custom schema, migrations should create a new user table

packages/better-auth/src/db/get-migration.ts

@@ -98,14 +98,17 @@ export function matchType(
  */
 async function getPostgresSchema(db: Kysely<unknown>): Promise<string> {
 	try {
-		const result = await sql<{ search_path: string }>`SHOW search_path`.execute(
-			db,
-		);
-		if (result.rows[0]?.search_path) {
+		const result = await sql<{
+			search_path?: string;
+			searchPath?: string;
+		}>`SHOW search_path`.execute(db);
+		const searchPath =
+			result.rows[0]?.search_path ?? result.rows[0]?.searchPath;
+		if (searchPath) {
 			// search_path can be a comma-separated list like "$user, public" or '"$user", public'
 			// Supabase may return escaped format like '"\$user", public'
 			// We want the first non-variable schema
-			const schemas = result.rows[0].search_path
+			const schemas = searchPath
 				.split(",")
 				.map((s) => s.trim())
 				// Remove quotes and filter out variables like $user
@@ -150,13 +153,18 @@ export async function getMigrations(config: BetterAuthOptions) {
 
 		// Verify the schema exists
 		try {
-			const schemaCheck = await sql<{ schema_name: string }>`
-				SELECT schema_name 
-				FROM information_schema.schemata 
+			const schemaCheck = await sql<{
+				schema_name?: string;
+				schemaName?: string;
+			}>`
+				SELECT schema_name
+				FROM information_schema.schemata
 				WHERE schema_name = ${currentSchema}
 			`.execute(db);
 
-			if (!schemaCheck.rows[0]) {
+			const schemaExists =
+				schemaCheck.rows[0]?.schema_name ?? schemaCheck.rows[0]?.schemaName;
+			if (!schemaExists) {
 				logger.warn(
 					`Schema '${currentSchema}' does not exist. Tables will be inspected from available schemas. Consider creating the schema first or checking your database configuration.`,
 				);
@@ -176,16 +184,17 @@ export async function getMigrations(config: BetterAuthOptions) {
 		// Get tables with their schema information
 		try {
 			const tablesInSchema = await sql<{
-				table_name: string;
+				table_name?: string;
+				tableName?: string;
 			}>`
-				SELECT table_name 
-				FROM information_schema.tables 
+				SELECT table_name
+				FROM information_schema.tables
 				WHERE table_schema = ${currentSchema}
 				AND table_type = 'BASE TABLE'
 			`.execute(db);
 
 			const tableNamesInSchema = new Set(
-				tablesInSchema.rows.map((row) => row.table_name),
+				tablesInSchema.rows.map((row) => row.table_name ?? row.tableName),
 			);
 
 			// Filter to only tables that exist in the target schema