Cannot read property 'charAt' of undefined

[DenisValeev]

app_1       | 
app_1       | 2018-02-16T14:03:22.213Z - info: deserializeUser: f93741fb-0d4c-4d15-b200-dd40ca233e08
app_1       | 2018-02-16T14:03:22.222Z - error:  TypeError: Cannot read property 'charAt' of undefined
app_1       |     at Object._decompress (/hackmd/node_modules/lz-string/libs/lz-string.js:473:24)
app_1       |     at Object.decompressFromBase64 (/hackmd/node_modules/lz-string/libs/lz-string.js:44:21)
app_1       |     at parseNoteIdByLZString (/hackmd/lib/models/note.js:196:33)
app_1       |     at /hackmd/node_modules/async/dist/async.js:3853:24
app_1       |     at replenish (/hackmd/node_modules/async/dist/async.js:946:17)
app_1       |     at iterateeCallback (/hackmd/node_modules/async/dist/async.js:931:17)
app_1       |     at /hackmd/node_modules/async/dist/async.js:906:16
app_1       |     at /hackmd/node_modules/async/dist/async.js:3858:13
app_1       |     at Model.<anonymous> (/hackmd/lib/models/note.js:186:26)
app_1       |     at Model.tryCatcher (/hackmd/node_modules/bluebird/js/release/util.js:16:23)
app_1       |     at Promise._settlePromiseFromHandler (/hackmd/node_modules/bluebird/js/release/promise.js:512:31)
app_1       |     at Promise._settlePromise (/hackmd/node_modules/bluebird/js/release/promise.js:569:18)
app_1       |     at Promise._settlePromise0 (/hackmd/node_modules/bluebird/js/release/promise.js:614:10)
app_1       |     at Promise._settlePromises (/hackmd/node_modules/bluebird/js/release/promise.js:693:18)
app_1       |     at Async._drainQueue (/hackmd/node_modules/bluebird/js/release/async.js:133:16)
app_1       |     at Async._drainQueues (/hackmd/node_modules/bluebird/js/release/async.js:143:10)
app_1       |     at Immediate.Async.drainQueues (/hackmd/node_modules/bluebird/js/release/async.js:17:14)
app_1       | Unhandled rejection Error: Callback was already called.
app_1       |     at /hackmd/node_modules/async/dist/async.js:903:32
app_1       |     at /hackmd/node_modules/async/dist/async.js:3858:13
app_1       |     at Model.<anonymous> (/hackmd/lib/models/note.js:190:22)
app_1       |     at Model.tryCatcher (/hackmd/node_modules/bluebird/js/release/util.js:16:23)
app_1       |     at Promise._settlePromiseFromHandler (/hackmd/node_modules/bluebird/js/release/promise.js:512:31)
app_1       |     at Promise._settlePromise (/hackmd/node_modules/bluebird/js/release/promise.js:569:18)
app_1       |     at Promise._settlePromise0 (/hackmd/node_modules/bluebird/js/release/promise.js:614:10)
app_1       |     at Promise._settlePromises (/hackmd/node_modules/bluebird/js/release/promise.js:689:18)
app_1       |     at Async._drainQueue (/hackmd/node_modules/bluebird/js/release/async.js:133:16)
app_1       |     at Async._drainQueues (/hackmd/node_modules/bluebird/js/release/async.js:143:10)
app_1       |     at Immediate.Async.drainQueues (/hackmd/node_modules/bluebird/js/release/async.js:17:14)
app_1       |     at runCallback (timers.js:672:20)
app_1       |     at tryOnImmediate (timers.js:645:5)
app_1       |     at processImmediate [as _immediateCallback] (timers.js:617:5)

[SISheogorath]

It would be helpful, when you provide some information about how you got this error.

As we need to reproduce it to fix it or at least make sure it doesn't appear anymore.

It actually seems to be a very special problem, as it's a function that is used everytime you open a note and never appeared by someone else (who reported it) right now.

[DenisValeev]

I could reproduce it here: https://hackmd-ce.herokuapp.com/zadachi

[jackycute]

@DenisValeev Hi, thanks for reporting this.
This issue is caused by the id extracted from the note url is an invalid base64 string.
Normally this should just be parsed as null or undefined string, but in this case it corrupted.

I would suggest to address this issue to the lib we use for encode UUID - LZString
https://github.com/pieroxy/lz-string
I'm able to reproduce this issue in http://pieroxy.net/blog/pages/lz-string/demo.html using dev tool.
The error line is in: https://github.com/pieroxy/lz-string/blob/master/libs/lz-string.js#L473

BTW, we should still response this error as 500 to user, I'll make a PR for this.

[SISheogorath]

Awesome @jackycute!

[DenisValeev]

Should create a page with an arbitrary name in the free url mode instead of a 500 error.

[SISheogorath]

This will automatically happen once the upstream is is fixed. As it should return an undefined or null and this will simply work as expected then, as this is already the current flow.

[SISheogorath]

Fixed by #743

[dekonnection]

I'm encountering this issue on a freshly 1.1.0-CE upgraded HackMD :|

Any idea, could I have made a mistake in the upgrade process ?