Broaden support for matrix spec versions (#12154)

Something of a compainion to
matrix-org/matrix-js-sdk#4014, but also covering the
issues discussed at
matrix-org/matrix-js-sdk#3915 (comment).

In short: we should not reject servers which only implement recent versions of
the spec. Doing so holds back the ecosystem by requiring all new servers to
implement features that nobody actually uses any more.

src/Lifecycle.ts

@@ -23,7 +23,7 @@ import { InvalidStoreError } from "matrix-js-sdk/src/errors";
 import { IEncryptedPayload } from "matrix-js-sdk/src/crypto/aes";
 import { QueryDict } from "matrix-js-sdk/src/utils";
 import { logger } from "matrix-js-sdk/src/logger";
-import { MINIMUM_MATRIX_VERSION } from "matrix-js-sdk/src/version-support";
+import { MINIMUM_MATRIX_VERSION, SUPPORTED_MATRIX_VERSIONS } from "matrix-js-sdk/src/version-support";
 
 import { IMatrixClientCreds, MatrixClientPeg } from "./MatrixClientPeg";
 import SecurityCustomisations from "./customisations/Security";
@@ -635,7 +635,7 @@ export async function restoreFromLocalStorage(opts?: { ignoreGuest?: boolean }):
             },
             false,
         );
-        checkServerVersions();
+        await checkServerVersions();
         return true;
     } else {
         logger.log("No previous session found.");
@@ -644,29 +644,34 @@ export async function restoreFromLocalStorage(opts?: { ignoreGuest?: boolean }):
 }
 
 async function checkServerVersions(): Promise<void> {
-    MatrixClientPeg.get()
-        ?.getVersions()
-        .then((response) => {
-            if (!response.versions.includes(MINIMUM_MATRIX_VERSION)) {
-                const toastKey = "LEGACY_SERVER";
-                ToastStore.sharedInstance().addOrReplaceToast({
-                    key: toastKey,
-                    title: _t("unsupported_server_title"),
-                    props: {
-                        description: _t("unsupported_server_description", {
-                            version: MINIMUM_MATRIX_VERSION,
-                            brand: SdkConfig.get().brand,
-                        }),
-                        acceptLabel: _t("action|ok"),
-                        onAccept: () => {
-                            ToastStore.sharedInstance().dismissToast(toastKey);
-                        },
-                    },
-                    component: GenericToast,
-                    priority: 98,
-                });
-            }
-        });
+    const client = MatrixClientPeg.get();
+    if (!client) return;
+    for (const version of SUPPORTED_MATRIX_VERSIONS) {
+        // Check if the server supports this spec version. (`isVersionSupported` caches the response, so this loop will
+        // only make a single HTTP request).
+        if (await client.isVersionSupported(version)) {
+            // we found a compatible spec version
+            return;
+        }
+    }
+
+    const toastKey = "LEGACY_SERVER";
+    ToastStore.sharedInstance().addOrReplaceToast({
+        key: toastKey,
+        title: _t("unsupported_server_title"),
+        props: {
+            description: _t("unsupported_server_description", {
+                version: MINIMUM_MATRIX_VERSION,
+                brand: SdkConfig.get().brand,
+            }),
+            acceptLabel: _t("action|ok"),
+            onAccept: () => {
+                ToastStore.sharedInstance().dismissToast(toastKey);
+            },
+        },
+        component: GenericToast,
+        priority: 98,
+    });
 }
 
 async function handleLoadSessionFailure(e: unknown): Promise<boolean> {

test/Lifecycle-test.ts

@@ -453,10 +453,7 @@ describe("Lifecycle", () => {
 
             it("should show a toast if the matrix server version is unsupported", async () => {
                 const toastSpy = jest.spyOn(ToastStore.sharedInstance(), "addOrReplaceToast");
-                mockClient.getVersions.mockResolvedValue({
-                    versions: ["r0.6.0"],
-                    unstable_features: {},
-                });
+                mockClient.isVersionSupported.mockImplementation(async (version) => version == "r0.6.0");
                 initLocalStorageMock({ ...localStorageSession });
 
                 expect(await restoreFromLocalStorage()).toEqual(true);