Warn on self change from settings > roles

playwright/e2e/settings/roles-permissions-room-settings-tab.spec.ts

@@ -37,6 +37,15 @@ test.describe("Roles & Permissions room settings tab", () => {
         // Change the role of Alice to Moderator (50)
         await combobox.selectOption("Moderator");
         await expect(combobox).toHaveValue("50");
+
+        // Should display a modal to warn that we are demoting the only admin user
+        const modal = await page.locator(".mx_Dialog", {
+            hasText: "Warning",
+        });
+        await expect(modal).toBeVisible();
+        // Click on the continue button in the modal
+        await modal.getByRole("button", { name: "Continue" }).click();
+
         const respPromise = page.waitForRequest("**/state/**");
         await applyButton.click();
         await respPromise;

src/components/views/settings/PowerLevelSelector.tsx

@@ -13,6 +13,8 @@ import { useMatrixClientContext } from "../../../contexts/MatrixClientContext";
 import PowerSelector from "../elements/PowerSelector";
 import { _t } from "../../../languageHandler";
 import SettingsFieldset from "./SettingsFieldset";
+import Modal from "../../../Modal";
+import QuestionDialog from "../dialogs/QuestionDialog";
 
 /**
  * Display in a fieldset, the power level of the users and allow to change them.
@@ -77,6 +79,13 @@ export function PowerLevelSelector({
     // No user to display, we return the children into fragment to convert it to JSX.Element type
     if (!users.length) return <>{children}</>;
 
+    // check at least one admin in the list
+    const roomHasAtLeastOneAdmin = (usersLevels: Record<string, number>): boolean => {
+        const userLevelValues = Object.values(usersLevels);
+        // At least one user as the pL 100 which means he is admin
+        return userLevelValues.some((uL) => uL === 100);
+    };
+
     return (
         <SettingsFieldset legend={title}>
             {users.map((userId) => {
@@ -96,7 +105,24 @@ export function PowerLevelSelector({
                         disabled={!canChange}
                         label={userId}
                         key={userId}
-                        onChange={(value) => setCurrentPowerLevel({ value, userId })}
+                        onChange={async (value) => {
+                            const userLevelsTmp = Object.assign({}, userLevels);
+                            userLevelsTmp[userId] = value;
+                            if (!roomHasAtLeastOneAdmin(userLevelsTmp)) {
+                                const { finished } = Modal.createDialog(QuestionDialog, {
+                                    title: _t("common|warning"),
+                                    description: <div>{_t("user_info|demote_self_confirm_room")}</div>,
+                                    button: _t("action|continue"),
+                                });
+                                const [confirmed] = await finished;
+                                if (!confirmed) {
+                                    // if cancel, we reput initial value
+                                    setCurrentPowerLevel({ value: userLevels[userId], userId });
+                                    return;
+                                }
+                            }
+                            setCurrentPowerLevel({ value, userId });
+                        }}
                     />
                 );
             })}

test/unit-tests/components/views/settings/PowerLevelSelector-test.tsx

@@ -61,7 +61,12 @@ describe("PowerLevelSelector", () => {
 
     it("should be able to change the power level of the current user", async () => {
         const onClick = jest.fn();
-        renderPLS({ onClick });
+        const userLevels = {
+            [currentUser]: 100,
+            "@alice:server.org": 100,
+            "@bob:server.org": 0,
+        };
+        renderPLS({ userLevels, onClick });
 
         // Until the power level is changed, the apply button should be disabled
         // compound button is using aria-disabled instead of the disabled attribute, we can't toBeDisabled on it
@@ -107,4 +112,58 @@ describe("PowerLevelSelector", () => {
 
         expect(screen.getByText("empty label")).toBeInTheDocument();
     });
+
+    it("should display modal warning if user is last admin", async () => {
+        const onClick = jest.fn();
+
+        renderPLS({ onClick });
+
+        // Until the power level is changed, the apply button should be disabled
+        // compound button is using aria-disabled instead of the disabled attribute, we can't toBeDisabled on it
+        expect(screen.getByRole("button", { name: "Apply" })).toHaveAttribute("aria-disabled", "true");
+
+        const select = screen.getByRole("combobox", { name: currentUser });
+        // Sanity check
+        expect(select).toHaveValue("100");
+
+        // Change current user power level to 50
+        await userEvent.selectOptions(select, "50");
+
+        // modal should appear because only admin in the room
+        expect(screen.findByText("WARNING")).toBeTruthy();
+
+        await userEvent.click(screen.getByRole("button", { name: "Continue" }));
+
+        expect(select).toHaveValue("50");
+        // After the user level changes, the apply button should be enabled
+        expect(screen.getByRole("button", { name: "Apply" })).toHaveAttribute("aria-disabled", "false");
+
+        // Click on Apply should call onClick with the new power level
+        await userEvent.click(screen.getByRole("button", { name: "Apply" }));
+        expect(onClick).toHaveBeenCalledWith(50, currentUser);
+    });
+
+    it("should display modal warning if user is last admin and return to initial value if user cancel", async () => {
+        const onClick = jest.fn();
+
+        renderPLS({ onClick });
+
+        // Until the power level is changed, the apply button should be disabled
+        // compound button is using aria-disabled instead of the disabled attribute, we can't toBeDisabled on it
+        expect(screen.getByRole("button", { name: "Apply" })).toHaveAttribute("aria-disabled", "true");
+
+        const select = screen.getByRole("combobox", { name: currentUser });
+        // Sanity check
+        expect(select).toHaveValue("100");
+
+        // Change current user power level to 50
+        await userEvent.selectOptions(select, "50");
+
+        // modal should appear because only admin in the room
+        expect(screen.findByText("WARNING")).toBeTruthy();
+
+        await userEvent.click(screen.getByRole("button", { name: "Cancel" }));
+        // the power level should be back to initial value
+        expect(select).toHaveValue("100");
+    });
 });

test/unit-tests/components/views/settings/tabs/room/RolesRoomSettingsTab-test.tsx

@@ -224,6 +224,9 @@ describe("RolesRoomSettingsTab", () => {
                     content: {
                         users: {
                             [cli.getUserId()!]: 100,
+                            // needs at least one remaning admin in the room if we want to demote our user
+                            // otherwise another modal will be displayed
+                            ["@admin:server"]: 100,
                         },
                     },
                 });