fix: unify duplicate-key error detection across routes

src/lib/server/services/errors.ts

@@ -0,0 +1,16 @@
+export function isUniqueViolation(err: unknown): boolean {
+	const msg = errorMessage(err);
+	const cause = errorMessage((err as { cause?: unknown } | null)?.cause);
+	const haystack = `${msg}\n${cause}`.toLowerCase();
+	return haystack.includes('duplicate key') || haystack.includes('unique');
+}
+
+function errorMessage(value: unknown): string {
+	if (value instanceof Error) return value.message;
+	if (typeof value === 'string') return value;
+	if (value && typeof value === 'object' && 'message' in value) {
+		const m = (value as { message?: unknown }).message;
+		if (typeof m === 'string') return m;
+	}
+	return '';
+}

src/routes/(admin)/admin/organizations/+page.server.ts

@@ -6,6 +6,7 @@ import {
 	createOrganization,
 	logAdminAction
 } from '$lib/server/services/admin';
+import { isUniqueViolation } from '$lib/server/services/errors';
 import { isEnabled } from '$lib/feature-flags';
 
 export const load: PageServerLoad = async ({ url }) => {
@@ -45,7 +46,7 @@ export const actions: Actions = {
 			);
 			return { created: true, createdName: values.name };
 		} catch (err: unknown) {
-			if (isDuplicateKeyError(err)) {
+			if (isUniqueViolation(err)) {
 				return fail(409, {
 					createErrors: { domain: 'create_duplicate_domain' } as Record<string, string>,
 					createValues: values
@@ -94,16 +95,3 @@ function validateCreateInput(input: CreateInput): Record<string, string> {
 	else if (!EMAIL_RE.test(input.signingEmail)) errors.signingEmail = 'create_invalid_email';
 	return errors;
 }
-
-function errMessage(value: unknown): string {
-	if (value instanceof Error) return value.message;
-	if (typeof value === 'string') return value;
-	return '';
-}
-
-function isDuplicateKeyError(err: unknown): boolean {
-	const top = errMessage(err);
-	const cause = errMessage((err as { cause?: unknown })?.cause);
-	const haystack = `${top}\n${cause}`;
-	return haystack.includes('duplicate key') || haystack.includes('unique');
-}

src/routes/(admin)/admin/organizations/[id]/+page.server.ts

@@ -12,6 +12,7 @@ import {
 	logAdminAction
 } from '$lib/server/services/admin';
 import { setImpersonation } from '$lib/server/auth/session';
+import { isUniqueViolation } from '$lib/server/services/errors';
 import { isEnabled } from '$lib/feature-flags';
 
 export const load: PageServerLoad = async ({ params }) => {
@@ -179,9 +180,7 @@ export const actions: Actions = {
 			);
 			return { userAdded: true, addedUserName: fullName };
 		} catch (err: unknown) {
-			const msg = err instanceof Error ? err.message : '';
-			const cause = (err as { cause?: { message?: string } })?.cause?.message ?? '';
-			if (`${msg}\n${cause}`.match(/duplicate key|unique/i)) {
+			if (isUniqueViolation(err)) {
 				return fail(409, {
 					addUserErrors: { email: 'addUser_duplicate_email' } as Record<string, string>,
 					addUserValues: { email, fullName, phone }

src/routes/(marketing)/register/+page.server.ts

@@ -4,6 +4,7 @@ import { db } from '$lib/server/db';
 import { organizations, users } from '$lib/server/db/schema';
 import { eq } from 'drizzle-orm';
 import { isEnabled } from '$lib/feature-flags';
+import { isUniqueViolation } from '$lib/server/services/errors';
 import { error } from '@sveltejs/kit';
 
 export function load() {
@@ -74,14 +75,7 @@ export const actions: Actions = {
 				.set({ contactUserId: user.id })
 				.where(eq(organizations.id, org.id));
 		} catch (err: unknown) {
-			const errStr = String(err instanceof Error ? (err.stack ?? err.message) : err);
-			const cause = (err as { cause?: { message?: string } } | null)?.cause;
-			const causeStr = cause ? String(cause.message ?? cause) : '';
-			if (
-				errStr.includes('unique') ||
-				errStr.includes('duplicate key') ||
-				causeStr.includes('duplicate key')
-			) {
+			if (isUniqueViolation(err)) {
 				return fail(409, {
 					errors: { domain: 'This domain is already registered' } as Record<string, string>,
 					values: { name }

src/routes/(portal)/portal/members/+page.server.ts

@@ -2,6 +2,7 @@ import type { Actions, PageServerLoad } from './$types';
 import { error, fail } from '@sveltejs/kit';
 import { isEnabled } from '$lib/feature-flags';
 import { listOrgUsers, addUser, removeUser, setContactPerson } from '$lib/server/services/users';
+import { isUniqueViolation } from '$lib/server/services/errors';
 
 export const load: PageServerLoad = async ({ parent }) => {
 	if (!isEnabled('portalMembers')) error(404, 'Not found');
@@ -31,7 +32,7 @@ export const actions: Actions = {
 		try {
 			await addUser(orgId, email, fullName, phone);
 		} catch (err: unknown) {
-			if (err instanceof Error && err.message.includes('unique')) {
+			if (isUniqueViolation(err)) {
 				return fail(409, { error: 'A user with this email already exists' });
 			}
 			throw err;

tests/unit/errors.test.ts

@@ -0,0 +1,49 @@
+import { describe, it, expect } from 'vitest';
+import { isUniqueViolation } from '$lib/server/services/errors';
+
+describe('isUniqueViolation', () => {
+	it('matches postgres "duplicate key value violates unique constraint" wording on message', () => {
+		const err = new Error('duplicate key value violates unique constraint "users_email_key"');
+		expect(isUniqueViolation(err)).toBe(true);
+	});
+
+	it('matches the bare "unique constraint" wording on message', () => {
+		const err = new Error('unique constraint violation on column email');
+		expect(isUniqueViolation(err)).toBe(true);
+	});
+
+	it('matches "duplicate key" wording wrapped in a cause', () => {
+		const err = new Error('insert failed') as Error & { cause: Error };
+		err.cause = new Error(
+			'duplicate key value violates unique constraint "organizations_domain_key"'
+		);
+		expect(isUniqueViolation(err)).toBe(true);
+	});
+
+	it('matches "unique" wording wrapped in a cause', () => {
+		const err = new Error('insert failed') as Error & { cause: Error };
+		err.cause = new Error('Unique constraint failed');
+		expect(isUniqueViolation(err)).toBe(true);
+	});
+
+	it('is case-insensitive', () => {
+		const err = new Error('DUPLICATE KEY value violates UNIQUE constraint');
+		expect(isUniqueViolation(err)).toBe(true);
+	});
+
+	it('reads message off a plain object with a message field', () => {
+		const err = { message: 'duplicate key value violates unique constraint' };
+		expect(isUniqueViolation(err)).toBe(true);
+	});
+
+	it('returns false for unrelated errors', () => {
+		expect(isUniqueViolation(new Error('connection refused'))).toBe(false);
+	});
+
+	it('returns false for non-error values', () => {
+		expect(isUniqueViolation(null)).toBe(false);
+		expect(isUniqueViolation(undefined)).toBe(false);
+		expect(isUniqueViolation(42)).toBe(false);
+		expect(isUniqueViolation({})).toBe(false);
+	});
+});