A data race was introduced in #9919 when the old synchronous storage
API was replaced with an async storage API. The problem arises when
`fetchWithCache` is called a second time while it's still processing
another call. In this case, the `cachedFetch` object can become
stale while blocked waiting for a fetch response, and result in a cache
being overwritten unintentionally.
See this example (options omitted for simplicity, and assuming an empty
initial cache):
```
await Promise.all([
fetchWithCache('https://metamask.io/foo'),
fetchWithCache('https://metamask.io/bar'),
]
```
The order of events could be as follows:
1. Empty cache retrieved for `/foo` route
2. Empty cache retrieved for `/bar` route
3. Call made to `/foo` route
4. Call made to `/bar` route
5. `/foo` response is added to the empty cache object retrieved in
step 1, then is saved in the cache.
6. `/bar` response is added to the empty cache object retrieved in
step 2, then is saved in the cache.
In step 6, the cache object saved would not contain the `/foo`
response set in step 5. As a result, `/foo` would never be cached.
This problem was resolved by embedding the URL being cached directly in
the cache key. This prevents simultaneous responses from overwriting
each others caches.
Technically a data race still exists when handing simultaneous
responses to the same route, but the result would be that the last call
to finish would overwrite the previous. This seems acceptable.
A data race was introduced in #9919 when the old synchronous storage
API was replaced with an async storage API. The problem arises when
`fetchWithCache` is called a second time while it's still processing
another call. In this case, the `cachedFetch` object can become
stale while blocked waiting for a fetch response, and result in a cache
being overwritten unintentionally.
See this example (options omitted for simplicity, and assuming an empty
initial cache):
```
await Promise.all([
fetchWithCache('https://metamask.io/foo'),
fetchWithCache('https://metamask.io/bar'),
]
```
The order of events could be as follows:
1. Empty cache retrieved for `/foo` route
2. Empty cache retrieved for `/bar` route
3. Call made to `/foo` route
4. Call made to `/bar` route
5. `/foo` response is added to the empty cache object retrieved in
step 1, then is saved in the cache.
6. `/bar` response is added to the empty cache object retrieved in
step 2, then is saved in the cache.
In step 6, the cache object saved would not contain the `/foo`
response set in step 5. As a result, `/foo` would never be cached.
This problem was resolved by embedding the URL being cached directly in
the cache key. This prevents simultaneous responses from overwriting
each others caches.
Technically a data race still exists when handing simultaneous
responses to the same route, but the result would be that the last call
to finish would overwrite the previous. This seems acceptable.
Previously all browser globals were allowed to be used anywhere by
ESLint because we had set the `env` property to `browser` in the ESLint
config. This has made it easy to accidentally use browser globals
(e.g. #8338), so it has been removed. Instead we now have a short list
of allowed globals.
All browser globals are now accessed as properties on `window`.
Unfortunately this change resulted in a few different confusing unit
test errors, as some of our unit tests setup assumed that a particular
global would be used via `window` or `global`. In particular,
`window.fetch` didn't work correctly because it wasn't patched by the
AbortController polyfill (only `global.fetch` was being patched).
The `jsdom-global` package we were using complicated matters by setting
all of the JSDOM `window` properties directly on `global`, overwriting
the `AbortController` for example.
The `helpers.js` test setup module has been simplified somewhat by
removing `jsdom-global` and constructing the JSDOM instance manually.
The JSDOM window is set on `window`, and a few properties are set on
`global` as well as needed by various dependencies. `node-fetch` and
the AbortController polyfill/patch now work as expected as well,
though `fetch` is only available on `window` now.
The `fetch-with-cache` utility was failing to actually cache anything.
It would cache an object with cache time and URL, and would return that
instead of a valid response. This resulted in the error:
`TypeError: fourByteResponse.json is not a function`
The utility was updated to call `.json()` within itself, and cache the
JSON response. The function signature was updated as well, to expect an
options object instead of just the `cacheRefreshTime` option. The
timeout was added to this options object, which helped with testing.
The utility method now also handles unsuccessfull responses, and
incompatible `fetch` options.
* Adds 4byte registry fallback to getMethodData() (#6435)
* Adds fetchWithCache to guard against unnecessary API calls
* Add custom fetch wrapper with abort on timeout
* Use opts and cacheRefreshTime in fetch-with-cache util
* Use custom fetch wrapper with timeout for fetch-with-cache
* Improve contract method data fetching (#6623)
* Remove async call from getTransactionActionKey()
* Stop blocking confirm screen rendering on method data loading, and base screen route on transactionCategory
* Remove use of withMethodData, fix use of knownMethodData, in relation to transaction-list-item.component
* Load data contract method data progressively, making it non-blocking; requires simplifying conf-tx-base lifecycle logic.
* Allow editing of gas price while loading on the confirm screen.
* Fix transactionAction component and its unit tests.
* Fix confirm transaction components for cases of route transitions within metamask.
* Only call toString on id if truthy in getNavigateTxData()
* Fix knownMethodData retrieval and data fetching from fourbyte
Filip Sekulic
ryanml
Brad Decker
Erik Marks
Mark Stacey
David Walsh
Whymarrh Whitby