Report preferences that were not saved

src/Application/User/Services/User.php

@@ -286,10 +286,20 @@ public function updatePass(int $userId, string $pass): void
      * @throws ConstraintException
      * @throws QueryException
      * @throws JsonException
+     * @throws ServiceException
      */
     public function updatePreferencesById(int $userId, UserPreferences $userPreferences): int
     {
-        return $this->userRepository->updatePreferencesById($userId, $userPreferences);
+        $affected = $this->userRepository->updatePreferencesById($userId, $userPreferences);
+
+        // An update whose WHERE matched nothing has saved nothing. Reporting success for it told
+        // the user their preferences had been stored — and the caller then refreshed the session
+        // with them, so the page even looked right until the next sign-in.
+        if ($affected === 0) {
+            throw ServiceException::error(__u('Error while updating the preferences'));
+        }
+
+        return $affected;
     }
 
     /**

tests/Integration/Infrastructure/Adapter/In/Web/Controllers/UserSettingsGeneral/UserSettingsGeneralTest.php

@@ -311,6 +311,49 @@ public function saveIsReportedAsFailedAndTheSessionIsLeftUntouchedWhenTheUpdateT
         );
     }
 
+    /**
+     * And the same when the update raises nothing at all but simply matches no row — the user's
+     * own row deleted from another session, say. It saved nothing, so it is reported as a failure
+     * and the session is left alone, rather than the page showing settings that exist nowhere.
+     *
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    #[Test]
+    public function saveIsReportedAsFailedWhenTheUpdateMatchesNoRow()
+    {
+        $this->databaseQueryResolver = function (QueryData $queryData): QueryResult {
+            $statement = $queryData->getQuery()->getStatement();
+
+            if (str_starts_with($statement, 'UPDATE') && str_contains($statement, 'preferences')) {
+                return new QueryResult([], 0, 0);
+            }
+
+            return new QueryResult([], 1, 100);
+        };
+
+        $container = $this->buildContainer(
+            IntegrationTestCase::buildRequest(
+                'post',
+                'index.php',
+                ['r' => 'userSettingsGeneral/save'],
+                self::fullPreferencesFields()
+            )
+        );
+
+        IntegrationTestCase::runApp($container);
+
+        $this->expectOutputString(
+            '{"status":"ERROR","description":"Error while updating the preferences","data":null}'
+        );
+
+        self::assertNull(
+            $this->refreshedSessionUserData,
+            'the session must not be refreshed with preferences that were never actually written'
+        );
+    }
+
     /**
      * Registers a resolver that captures the bind values of the UPDATE issued against the
      * preferences column into {@see $capturedUpdateBindValues}. Every other query on the

tests/Unit/Application/User/Services/UserTest.php

@@ -142,6 +142,30 @@ public function testUpdatePreferencesById()
         $this->assertEquals(10, $out);
     }
 
+    /**
+     * A user whose row is no longer there has not had their preferences saved, and saying so beats
+     * reporting success — the caller refreshes the session with what it thinks was stored, so
+     * without this the page looks right until the next sign-in throws it away.
+     *
+     * @throws Exception
+     * @throws ServiceException
+     */
+    public function testUpdatePreferencesByIdOfAUserThatIsNotThereIsReported()
+    {
+        $userPreferences = UserDataGenerator::factory()->buildUserPreferencesData();
+
+        $this->userRepository
+            ->expects($this->once())
+            ->method('updatePreferencesById')
+            ->with(100, $userPreferences)
+            ->willReturn(0);
+
+        $this->expectException(ServiceException::class);
+        $this->expectExceptionMessage('Error while updating the preferences');
+
+        $this->user->updatePreferencesById(100, $userPreferences);
+    }
+
     public function testGetAll()
     {
         $user = UserDataGenerator::factory()->buildUserData();