Dev errors getting swallowed

[shilman]

When running in dev mode, some errors are getting swallowed with the following error message:

[UnhandledPromiseRejection: This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). The promise rejected with the reason "[object Object]".] {
  code: 'ERR_UNHANDLED_REJECTION'
}

This code is breaking:

https://github.com/storybookjs/storybook/blob/next/code/lib/cli/src/dev.ts#L20-L35

The weird error handling code is to deal with errors being thrown OR a webpack Stats object being throw, and the code used to be

await buildDevStandalone(options);

However, a recent update changed the code to:

await withTelemetry('dev', { presetOptions: options }, () => buildDevStandalone(options));

Wrapping the calling code in withTelemetry somehow leads to the error getting unhandled. Although how this happens is unclear.

[shilman]

We found that the culprit was the following two lines.

A direct access to the cache:

storybook/code/lib/core-server/src/withTelemetry.ts

Line 52 in a78ef8d

(await cache.get('enableCrashReports')) ?? (await cache.get('enableCrashreports'));

A call to a function that accesses the cache:

storybook/code/lib/core-server/src/withTelemetry.ts

Line 74 in a78ef8d

const precedingUpgrade = await getPrecedingUpgrade();

Despite both lines being wrapped in try/catch, when something goes wrong in the cache it takes all of Node down in strange ways. Since #20136 most recently touched the cache, we are trying to get back to the previous state for now.

[shilman]

Possible workarounds:

1. Run build-storybook instead to see the underlying error
2. Run storybook --ci to possibly see the underlying error

[ndelangen]

After a lot of debugging together @shilman and I discovered that core-common cache.get seems to be at fault.
No idea what's going on, but it looks like when this fails it's fatal, and node exits immediately.

I might investigate a replacement for the current cache mechanism.

[shilman]

Ta-da!! I just released https://github.com/storybookjs/storybook/releases/tag/v7.0.0-beta.2 containing PR #20177 that references this issue. Upgrade today to the @next NPM tag to try it out!

npx sb upgrade --prerelease

Closing this issue. Please re-open if you think there's still more to do.