fix(clerk-js): Improve solution for saml and hidden password field

.changeset/twenty-maps-train.md

@@ -0,0 +1,2 @@
+---
+---

packages/clerk-js/src/ui/components/SignIn/SignInStart.tsx

@@ -1,6 +1,6 @@
 import { useClerk } from '@clerk/shared/react';
 import { isWebAuthnAutofillSupported, isWebAuthnSupported } from '@clerk/shared/webauthn';
-import type { ClerkAPIError, SignInCreateParams } from '@clerk/types';
+import type { ClerkAPIError, SignInCreateParams, SignInResource } from '@clerk/types';
 import { useEffect, useLayoutEffect, useMemo, useRef, useState } from 'react';
 
 import { ERROR_CODES } from '../../../core/constants';
@@ -245,18 +245,28 @@ export function _SignInStart(): JSX.Element {
     } as SignInCreateParams;
   };
 
+  const safePasswordSignInForSamlInstance = (
+    signInCreatePromise: Promise<SignInResource>,
+    fields: Array<FormControlState<string>>,
+  ) => {
+    return signInCreatePromise.then(signInResource => {
+      if (!userSettings.saml.enabled) {
+        return signInResource;
+      }
+      /**
+       * For SAML enabled instances, perform sign in with password only when it is allowed for the identified user.
+       */
+      const passwordField = fields.find(f => f.name === 'password')?.value;
+      if (!passwordField || signInResource.supportedFirstFactors.some(ff => ff.strategy === 'saml')) {
+        return signInResource;
+      }
+      return signInResource.attemptFirstFactor({ strategy: 'password', password: passwordField });
+    });
+  };
+
   const signInWithFields = async (...fields: Array<FormControlState<string>>) => {
     try {
-      const res = await signIn.create(buildSignInParams(fields)).then(signInResource => {
-        /**
-         * For SAML enabled instances, perform sign in with password only when it is allowed for the identified user.
-         */
-        const passwordField = fields.find(f => f.name === 'password')?.value;
-        if (!passwordField || signInResource.supportedFirstFactors.some(ff => ff.strategy === 'saml')) {
-          return signInResource;
-        }
-        return signInResource.attemptFirstFactor({ strategy: 'password', password: passwordField });
-      });
+      const res = await safePasswordSignInForSamlInstance(signIn.create(buildSignInParams(fields)), fields);
 
       switch (res.status) {
         case 'needs_identifier':

packages/clerk-js/src/ui/utils/test/fixtures.ts

@@ -178,6 +178,7 @@ const createBaseUserSettings = (): UserSettingsJSON => {
     attributes: { ...attributeConfig },
     actions: { delete_self: false, create_organization: false },
     social: { ...socialConfig },
+    saml: { enabled: false },
     sign_in: {
       second_factor: {
         required: false,