🤖 Merge PR #48140 [next-auth] Allow session to be null or undefined by @bjohn465

While the session data is being fetched,
`useSession` will return `undefined`.
If a session doesn't exist,
`useSession` will return `null`.

The result of `useSession`
is commonly passed to the `Provider` component
(e.g. see the examples at
https://next-auth.js.org/getting-started/client#provider),
and it seems to allow the `undefined` and `null` values
for the `session` prop,
so allow them in the type information, too.

types/next-auth/client.d.ts

@@ -25,7 +25,7 @@ interface SessionProvider extends GenericObject {
 }
 
 interface ContextProviderProps {
-    session: Session;
+    session: Session | null | undefined;
     options?: SetOptionsParams;
 }
 
@@ -43,7 +43,7 @@ interface NextContext {
     ctx?: { req: IncomingMessage };
 }
 
-declare function useSession(): [Session, boolean];
+declare function useSession(): [Session | null | undefined, boolean];
 declare function providers(): Promise<GetProvidersResponse | null>;
 declare const getProviders: typeof providers;
 declare function session(

types/next-auth/next-auth-tests.ts

@@ -190,7 +190,7 @@ const session = {
     expires: '1234',
 };
 
-// $ExpectType [Session, boolean]
+// $ExpectType [Session | null | undefined, boolean]
 client.useSession();
 
 // $ExpectType Promise<Session | null>
@@ -230,6 +230,28 @@ client.Provider({
     },
 });
 
+// $ExpectType ReactElement<any, any> | null
+client.Provider({
+    session,
+});
+
+// $ExpectType ReactElement<any, any> | null
+client.Provider({
+    session: undefined,
+    options: {},
+});
+
+// $ExpectType ReactElement<any, any> | null
+client.Provider({
+    session: null,
+    options: {
+        baseUrl: 'https://foo.com',
+        basePath: '/',
+        clientMaxAge: 1234,
+        keepAlive: 4321,
+    },
+});
+
 // --------------------------------------------------------------------------
 // Providers
 // --------------------------------------------------------------------------