fix: Avoid redirecting to login with an incomplete configuration

lib/AppInfo/Application.php

@@ -167,7 +167,13 @@ public function boot(IBootContext $context): void {
 				}
 
 				$multipleUserBackEnds = $samlSettings->allowMultipleUserBackEnds();
-				$configuredIdps = $samlSettings->getListOfIdps();
+				$configuredIdps = $samlSettings->getListOfIdps(true);
+				// If no IdP has the minimum required config (entityId + SSO URL), fall through to normal login
+				// only for regular SAML mode. Environment-variable mode can still redirect to SAMLController::login()
+				// without requiring configured IdP metadata.
+				if ($type === 'saml' && empty($configuredIdps)) {
+					return;
+				}
 				$showLoginOptions = $type !== 'environment-variable' && ($multipleUserBackEnds || count($configuredIdps) > 1);
 
 				if ($redirectSituation === true && $showLoginOptions) {

lib/SAMLSettings.php

@@ -90,11 +90,17 @@ public function __construct(
 	 * @return array<int, string>
 	 * @throws Exception
 	 */
-	public function getListOfIdps(): array {
+	public function getListOfIdps(bool $onlyComplete = false): array {
 		$this->ensureConfigurationsLoaded();
 
 		$result = [];
 		foreach ($this->configurations as $configID => $config) {
+			if ($onlyComplete
+				&& (trim(($config['idp-entityId'] ?? '')) === ''
+				|| trim(($config['idp-singleSignOnService.url'] ?? '')) === '')
+			) {
+				continue;
+			}
 			// no fancy array_* method, because there might be thousands
 			$result[$configID] = $config['general-idp0_display_name'] ?? '';
 		}

tests/unit/SAMLSettingsTest.php

@@ -0,0 +1,127 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\User_SAML\Tests;
+
+use OCA\User_SAML\Db\ConfigurationsMapper;
+use OCA\User_SAML\SAMLSettings;
+use OCP\AppFramework\Services\IAppConfig;
+use OCP\IConfig;
+use OCP\ISession;
+use OCP\IURLGenerator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class SAMLSettingsTest extends TestCase {
+	private IURLGenerator&MockObject $urlGenerator;
+	private IConfig&MockObject $config;
+	private IAppConfig&MockObject $appConfig;
+	private ISession&MockObject $session;
+	private ConfigurationsMapper&MockObject $mapper;
+	private SAMLSettings $samlSettings;
+
+	#[\Override]
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->urlGenerator = $this->createMock(IURLGenerator::class);
+		$this->config = $this->createMock(IConfig::class);
+		$this->appConfig = $this->createMock(IAppConfig::class);
+		$this->session = $this->createMock(ISession::class);
+		$this->mapper = $this->createMock(ConfigurationsMapper::class);
+
+		$this->samlSettings = new SAMLSettings(
+			$this->urlGenerator,
+			$this->config,
+			$this->appConfig,
+			$this->session,
+			$this->mapper,
+		);
+	}
+
+	private static function dataGetListOfIdps(): array {
+		return [
+			'empty-all' => [
+				false,
+				[],
+				[],
+			],
+			'empty-complete' => [
+				true,
+				[],
+				[],
+			],
+			'entityId-and-ssoUrl-missing' => [
+				true,
+				[
+					1 => [
+						'general-idp0_display_name' => 'My IdP',
+						// no idp-entityId, no idp-singleSignOnService.url
+					],
+				],
+				[],
+			],
+			'only-whitespace' => [
+				true,
+				[
+					1 => [
+						'general-idp0_display_name' => 'My IdP',
+						'idp-entityId' => '   ',
+						'idp-singleSignOnService.url' => "\t",
+					],
+				],
+				[],
+			],
+			'configured' => [
+				true,
+				[
+					1 => [
+						'general-idp0_display_name' => 'My IdP',
+						'idp-entityId' => 'https://idp.example.com',
+						'idp-singleSignOnService.url' => 'https://idp.example.com/sso',
+					],
+				],
+				[1 => 'My IdP'],
+			],
+			'partially-configured' => [
+				true,
+				[
+					1 => [
+						'general-idp0_display_name' => 'Configured IdP',
+						'idp-entityId' => 'https://idp.example.com',
+						'idp-singleSignOnService.url' => 'https://idp.example.com/sso',
+					],
+					2 => [
+						'general-idp0_display_name' => 'Missing SSO URL',
+						'idp-entityId' => 'https://idp2.example.com',
+						// missing idp-singleSignOnService.url
+					],
+					3 => [
+						'general-idp0_display_name' => 'Missing Entity ID',
+						// missing idp-entityId
+						'idp-singleSignOnService.url' => 'https://idp3.example.com/sso',
+					],
+				],
+				[1 => 'Configured IdP'],
+			],
+		];
+	}
+
+	#[DataProvider('dataGetListOfIdps')]
+	public function testGetListOfIdps(bool $onlyComplete, array $configs, array $expected): void {
+		$this->mapper->expects($this->once())
+			->method('getAll')
+			->willReturn($configs);
+
+		$result = $this->samlSettings->getListOfIdps($onlyComplete);
+
+		$this->assertSame($expected, $result);
+	}
+}