fix: resume private share bundles after sign-in (Closes #1004)

tests/test_login_frontend.py

@@ -569,6 +569,51 @@ async function destination(continuation) {{
     }
 
 
+def test_token_and_passkey_login_resume_only_the_private_share_bundle():
+    harness = f"""
+const createLoginController = require({json.dumps(str(LOGIN_JS))});
+const credential = {{
+  id:'credential-id', type:'public-key', rawId:Uint8Array.from([1]).buffer,
+  response:{{authenticatorData:Uint8Array.from([2]).buffer,
+    clientDataJSON:Uint8Array.from([3]).buffer,
+    signature:Uint8Array.from([4]).buffer,userHandle:null}},
+}};
+async function destination(continuation, authentication) {{
+  let replaced = null;
+  const controller = createLoginController({{
+    form:{{reset:()=>{{}}}}, status:{{textContent:''}}, button:{{disabled:false}},
+    passkeyButton:{{disabled:false}}, credentials:{{get:async()=>credential}},
+    fetchImpl:async url => url.endsWith('/options')
+      ? new Response(JSON.stringify({{challenge:'AQID',allowCredentials:[]}}),
+          {{status:200,headers:{{'Content-Type':'application/json'}}}})
+      : new Response('{{}}',{{status:200}}),
+    location:{{replace:value=>replaced=value}}, continuation,
+  }});
+  if (authentication === 'passkey') await controller.signInWithPasskey('Phone');
+  else await controller.submit('operator-token');
+  return replaced;
+}}
+(async()=>process.stdout.write(JSON.stringify({{
+  token:await destination('./?launch=new&shared=bundle','token'),
+  passkey:await destination('./?launch=new&shared=bundle','passkey'),
+  extra:await destination('./?launch=new&shared=bundle&title=leak','token'),
+  duplicate:await destination('./?launch=new&shared=bundle&shared=bundle','token'),
+  wrongLaunch:await destination('./?launch=agenda&shared=bundle','token'),
+}})))().catch(error=>{{console.error(error);process.exit(1);}});
+"""
+    result = subprocess.run(
+        ["node", "-e", harness], text=True, capture_output=True, check=True
+    )
+
+    assert json.loads(result.stdout) == {
+        "token": "./?launch=new&shared=bundle",
+        "passkey": "./?launch=new&shared=bundle",
+        "extra": "./",
+        "duplicate": "./",
+        "wrongLaunch": "./",
+    }
+
+
 @pytest.mark.anyio
 async def test_login_page_loads_rate_limit_controller():
     html = await login()