Degration of indexeddb to MemoryStore does not work anymore

[schmop]

Describe the bug
If the indexeddb throws an exception, normally the store would have degraded on a MemoryStore.
This does not longer work, because of the switch to the async-notation. The exceptions do not get caught and the degration will not be started.

To Reproduce
Steps to reproduce the behavior:

1. Client startup with custom indexeddb in store

import db from './customindexeddb';

let opts = {
  store: new matrixcs.IndexedDBStore(
    indexeddb: db,
    dbName: 'matrix-store',
  ),
  baseUrl: "https://matrix.org",
};

var client = matrixcs.createClient(opts);
client.store.startup();

2. customindexeddb is programmed to throw on reading from object stores
3. MatrixClient crashes, but does not degrade to MemoryStore

Expected behavior
An error is thrown in the console, indexeddb will not be used anymore, and the backend store falls back to the MemoryStore.

[t3chguy]

Can you share any errors or stack traces maybe?

[schmop]

Not sure if this helps:

Stack trace

logger.js?3eb4:59 IndexedDBStore.startup: connecting to backend
logger.js?3eb4:59 LocalIndexedDBStoreBackend.connect: connecting...
logger.js?3eb4:59 LocalIndexedDBStoreBackend.connect: awaiting connection...
logger.js?3eb4:59 LocalIndexedDBStoreBackend.connect: connected
logger.js?3eb4:59 LocalIndexedDBStoreBackend: loading account data...
logger.js?3eb4:59 LocalIndexedDBStoreBackend: loading sync data...
logger.js?3eb4:59 LocalIndexedDBStoreBackend: loaded account data
logger.js?3eb4:59 LocalIndexedDBStoreBackend: loaded sync data
logger.js?3eb4:59 LocalIndexedDBStoreBackend: loaded initial data
logger.js?3eb4:59 IndexedDBStore.startup: loading presence events
logger.js?3eb4:59 IndexedDBStore.startup: processing presence events
logger.js?3eb4:59 Fetching new TURN credentials
logger.js?3eb4:59 Getting saved sync token...
logger.js?3eb4:59 Getting push rules...
logger.js?3eb4:59 Got saved sync token
logger.js?3eb4:59 Getting saved sync...
logger.js?3eb4:59 Got reply from saved sync, exists? false
logger.js?3eb4:59 Got push rules
logger.js?3eb4:59 Checking lazy load status...
logger.js?3eb4:59 Checking whether lazy loading has changed in store...

indexeddb-local-backend.js?f817:87 Uncaught (in promise) Error: Query failed: Error: Integrity check failed
    at EncryptedRequest.query.onerror (indexeddb-local-backend.js?f817:87:1)
    at DecryptingCursor.get (decrypting-cursor.js?34a9:11:1)
    at eval (indexeddb-local-backend.js?f817:574:1)
    at EncryptedRequest.query.onsuccess (indexeddb-local-backend.js?f817:99:1)
    at IDBRequest._this3.parent.<computed> (cascading-event-target.js?cd68:37:1)
query.onerror @ indexeddb-local-backend.js?f817:87
get @ decrypting-cursor.js?34a9:11
eval @ indexeddb-local-backend.js?f817:574
query.onsuccess @ indexeddb-local-backend.js?f817:99
_this3.parent.<computed> @ cascading-event-target.js?cd68:37
await in _this3.parent.<computed> (async)
getPushRules @ sync.js?4667:540
await in getPushRules (async)
sync @ sync.js?4667:685
startClient @ client.js?62ec:466
await in startClient (async)

_callee$ @ index.js?0606:364
tryCatch @ runtime.js?96cf:63
invoke @ runtime.js?96cf:294
eval @ runtime.js?96cf:119
asyncGeneratorStep @ index.js:83
_next @ index.js:85
Promise.then (async)
asyncGeneratorStep @ index.js:83
_next @ index.js:85
Promise.then (async)
asyncGeneratorStep @ index.js:83
_next @ index.js:85
eval @ index.js:85
eval @ index.js:85
setupClient @ index.js?0606:257
finalizeAuthentication @ index.js?0606:222
retrieveUserInfo @ index.js?0606:244
login @ index.js?0606:197
eval @ index.js?0606:832
./assets/src/backend/index.js @ backend.cab1c6b4.js:18
__webpack_require__ @ standalone.2e25e533.js:9841
Promise.then (async)
_callee2$ @ messenger-view.vue?f34c:271
tryCatch @ runtime.js?96cf:63
invoke @ runtime.js?96cf:294
eval @ runtime.js?96cf:119
asyncGeneratorStep @ index.js??vue-loader-options!./assets/src/components/messenger-view.vue?vue&type=script&lang=js&:64
_next @ index.js??vue-loader-options!./assets/src/components/messenger-view.vue?vue&type=script&lang=js&:66
eval @ index.js??vue-loader-options!./assets/src/components/messenger-view.vue?vue&type=script&lang=js&:66
eval @ index.js??vue-loader-options!./assets/src/components/messenger-view.vue?vue&type=script&lang=js&:66
mounted @ messenger-view.vue?f34c:270
callHook @ vue.esm.js:2920
insert @ vue.esm.js:4153
invokeInsertHook @ vue.esm.js:5948
patch @ vue.esm.js:6167
Vue._update @ vue.esm.js:2659
updateComponent @ vue.esm.js:2787
get @ vue.esm.js:3141
Watcher @ vue.esm.js:3130
mountComponent @ vue.esm.js:2794
Vue.$mount @ vue.esm.js:8528
Vue.$mount @ vue.esm.js:10925
Vue._init @ vue.esm.js:4628
Vue @ vue.esm.js:4717
init @ chat-standalone.js?babe:11
i.init @ iserv.b806a41b.js:2
(anonym) @ iserv.b806a41b.js:2
u @ jquery.c212efcd.js:2
fireWith @ jquery.c212efcd.js:2
ready @ jquery.c212efcd.js:2
R @ jquery.c212efcd.js:2

It references following Code snippets:

// indexeddb-local-backend.js : 87
function selectQuery(store, keyRange, resultMapper) {
  const query = store.openCursor(keyRange);
  return new Promise((resolve, reject) => {
    const results = [];

    query.onerror = () => {
      reject(new Error("Query failed: " + query.error));
    }; // collect results
    // [...]
}

This error is not caught from the degradable-method in indexeddb.ts:

// indexeddb.ts:292
    private degradable<A extends Array<any>, R = void>(
        func: DegradableFn<A, R>,
        fallback?: string,
    ): DegradableFn<A, R> {
        const fallbackFn = super[fallback];

        return async (...args) => {
            try {
                return func.call(this, ...args); // THIS DOES NOT CATCH THE FAILING PROMISE
            } catch (e) {
            [...]            

[t3chguy]

Yup good spot, has a missing await