do not offer to change display name or password, if not possible.

apps/provisioning_api/lib/Controller/AUserData.php

@@ -22,6 +22,7 @@
 namespace OCA\Provisioning_API\Controller;
 
 use OC\Accounts\AccountManager;
+use OC\User\Backend;
 use OCP\AppFramework\OCS\OCSException;
 use OCP\AppFramework\OCS\OCSNotFoundException;
 use OCP\AppFramework\OCSController;
@@ -32,6 +33,8 @@
 use OCP\IRequest;
 use OCP\IUserManager;
 use OCP\IUserSession;
+use OCP\User\Backend\ISetDisplayNameBackend;
+use OCP\User\Backend\ISetPasswordBackend;
 
 abstract class AUserData extends OCSController {
 
@@ -125,6 +128,12 @@ protected function getUserData(string $userId): array {
 		$data['language'] = $this->config->getUserValue($targetUserObject->getUID(), 'core', 'lang');
 		$data['locale'] = $this->config->getUserValue($targetUserObject->getUID(), 'core', 'locale');
 
+		$backend = $targetUserObject->getBackend();
+		$data['backendCapabilities'] = [
+			'setDisplayName' => $backend instanceof ISetDisplayNameBackend || $backend->implementsActions(Backend::SET_DISPLAYNAME),
+			'setPassword' => $backend instanceof ISetPasswordBackend || $backend->implementsActions(Backend::SET_PASSWORD),
+		];
+
 		return $data;
     }
 

apps/provisioning_api/tests/Controller/UsersControllerTest.php

@@ -38,25 +38,22 @@
 use OCA\FederatedFileSharing\FederatedShareProvider;
 use OCA\Provisioning_API\FederatedFileSharingFactory;
 use OCP\App\IAppManager;
-use OCP\AppFramework\OCS\OCSException;
 use OCP\Mail\IEMailTemplate;
 use OC\Settings\Mailer\NewUserMailHelper;
 use OC\SubAdmin;
 use OCA\Provisioning_API\Controller\UsersController;
 use OCP\AppFramework\Http\DataResponse;
-use OCP\Defaults;
 use OCP\IConfig;
 use OCP\IGroup;
 use OCP\ILogger;
 use OCP\IL10N;
 use OCP\IRequest;
-use OCP\IURLGenerator;
 use OCP\IUser;
 use OCP\IUserManager;
 use OCP\IUserSession;
 use OCP\L10N\IFactory;
-use OCP\Mail\IMailer;
 use OCP\Security\ISecureRandom;
+use OCP\UserInterface;
 use PHPUnit_Framework_MockObject_MockObject;
 use Test\TestCase;
 
@@ -800,6 +797,12 @@ public function testGetUserDataAsAdmin() {
 			->method('fillStorageInfo')
 			->with('UID')
 			->will($this->returnValue(['DummyValue']));
+
+		$backend = $this->createMock(UserInterface::class);
+		$backend->expects($this->any())
+			->method('implementsActions')
+			->willReturn(true);
+
 		$targetUser
 			->expects($this->once())
 			->method('getDisplayName')
@@ -816,6 +819,10 @@ public function testGetUserDataAsAdmin() {
 			->expects($this->once())
 			->method('getBackendClassName')
 			->will($this->returnValue('Database'));
+		$targetUser
+			->expects($this->once())
+			->method('getBackend')
+			->willReturn($backend);
 		$targetUser
 			->expects($this->exactly(6))
 			->method('getUID')
@@ -838,6 +845,10 @@ public function testGetUserDataAsAdmin() {
 			'groups' => ['group0', 'group1', 'group2'],
 			'language' => 'de',
 			'locale' => null,
+			'backendCapabilities' => [
+				'setDisplayName' => true,
+				'setPassword' => true,
+			]
 		];
 		$this->assertEquals($expected, $this->invokePrivate($this->api, 'getUserData', ['UID']));
 	}
@@ -906,6 +917,12 @@ public function testGetUserDataAsSubAdminAndUserIsAccessible() {
 			->method('fillStorageInfo')
 			->with('UID')
 			->will($this->returnValue(['DummyValue']));
+
+		$backend = $this->createMock(UserInterface::class);
+		$backend->expects($this->any())
+			->method('implementsActions')
+			->willReturn(true);
+
 		$targetUser
 			->expects($this->once())
 			->method('getDisplayName')
@@ -922,6 +939,10 @@ public function testGetUserDataAsSubAdminAndUserIsAccessible() {
 			->expects($this->once())
 			->method('getBackendClassName')
 			->will($this->returnValue('Database'));
+		$targetUser
+			->expects($this->once())
+			->method('getBackend')
+			->willReturn($backend);
 		$targetUser
 			->expects($this->exactly(6))
 			->method('getUID')
@@ -954,6 +975,10 @@ public function testGetUserDataAsSubAdminAndUserIsAccessible() {
 			'groups' => [],
 			'language' => 'da',
 			'locale' => null,
+			'backendCapabilities' => [
+				'setDisplayName' => true,
+				'setPassword' => true,
+			]
 		];
 		$this->assertEquals($expected, $this->invokePrivate($this->api, 'getUserData', ['UID']));
 	}
@@ -1054,6 +1079,12 @@ public function testGetUserDataAsSubAdminSelfLookup() {
 			->method('fillStorageInfo')
 			->with('UID')
 			->will($this->returnValue(['DummyValue']));
+
+		$backend = $this->createMock(UserInterface::class);
+		$backend->expects($this->atLeastOnce())
+			->method('implementsActions')
+			->willReturn(false);
+
 		$targetUser
 			->expects($this->once())
 			->method('getDisplayName')
@@ -1078,6 +1109,10 @@ public function testGetUserDataAsSubAdminSelfLookup() {
 			->expects($this->once())
 			->method('getBackendClassName')
 			->will($this->returnValue('Database'));
+		$targetUser
+			->expects($this->once())
+			->method('getBackend')
+			->willReturn($backend);
 		$this->config
 			->expects($this->at(0))
 			->method('getUserValue')
@@ -1110,6 +1145,10 @@ public function testGetUserDataAsSubAdminSelfLookup() {
 			'groups' => [],
 			'language' => 'ru',
 			'locale' => null,
+			'backendCapabilities' => [
+				'setDisplayName' => false,
+				'setPassword' => false,
+			]
 		];
 		$this->assertEquals($expected, $this->invokePrivate($this->api, 'getUserData', ['UID']));
 	}

lib/public/IUser.php

@@ -26,6 +26,8 @@
 
 namespace OCP;
 
+use OCP\UserInterface;
+
 /**
  * Interface IUser
  *
@@ -111,6 +113,7 @@ public function getBackendClassName();
 	/**
 	 * Get the backend for the current user object
 	 *
+	 * @return UserInterface
 	 * @since 15.0.0
 	 */
 	public function getBackend();

settings/src/components/userList/userRow.vue

@@ -42,13 +42,17 @@
 		<!-- dirty hack to ellipsis on two lines -->
 		<div class="name">{{user.id}}</div>
 		<form class="displayName" :class="{'icon-loading-small': loading.displayName}" v-on:submit.prevent="updateDisplayName">
-			<input :id="'displayName'+user.id+rand" type="text"
-					:disabled="loading.displayName||loading.all"
-					:value="user.displayname" ref="displayName"
-					autocomplete="new-password" autocorrect="off" autocapitalize="off" spellcheck="false" />
-			<input type="submit" class="icon-confirm" value="" />
+			<template v-if="user.backendCapabilities.setDisplayName">
+				<input v-if="user.backendCapabilities.setDisplayName"
+						:id="'displayName'+user.id+rand" type="text"
+						:disabled="loading.displayName||loading.all"
+						:value="user.displayname" ref="displayName"
+						autocomplete="new-password" autocorrect="off" autocapitalize="off" spellcheck="false" />
+				<input v-if="user.backendCapabilities.setDisplayName" type="submit" class="icon-confirm" value="" />
+			</template>
+			<div v-else class="name" v-tooltip.auto="t('settings', 'The backend does not support changing the display name')">{{user.displayname}}</div>
 		</form>
-		<form class="password" v-if="settings.canChangePassword" :class="{'icon-loading-small': loading.password}"
+		<form class="password" v-if="settings.canChangePassword && user.backendCapabilities.setPassword" :class="{'icon-loading-small': loading.password}"
 			  v-on:submit.prevent="updatePassword">
 			<input :id="'password'+user.id+rand" type="password" required
 					:disabled="loading.password||loading.all" :minlength="minPasswordLength"