Typescript compiler hangs and starts eating memory

[davyvanlaere]

TypeScript Version:
1.8.0-beta

Code

    return this.http.request(url, request)
        .catch(initialError => {
            if (initialError && initialError.status === 401 && isSecureCall === true) {
                // token might be expired, try to refresh token
                return me.authService.refreshAuthentication().flatMap((authenticationResult:AuthenticationResult) => {
                    if (authenticationResult.IsAuthenticated == true) {
                        // retry with new token
                        me.authService.setAuthorizationHeader(request.headers);
                        return this.http.request(url, request);
                    }
                    return Observable.throw(initialError);
                });
            }
            else {
                return Observable.throw(initialError);
            }
        });

Expected behavior:

This code has compiled and worked before. (this is a snippet from an angular2 application: if an authenticated request fails because the token has expired, the code tries to use a refresh token to get a new token and retry the request).

Actual behavior:

The compiler starts to hang

I have stripped down my project to the bare minimum to illustrate the problem.
To reproduce; clone this repo:

https://github.com/davyvanlaere/TypescriptCompilerIssue

Then run "npm install", followed by "tsc": the compiler will hang, and the process "Evented I/O for V8 Javascript" will start to eat memory (i let it run for a while and killed it at 1.3gb).

It has something to do with the types of the return statements. If you the replace 2nd "return this.http.request(url, request);" line with "return Observable.throw(initialError);", the compiuler will not hang.

[vladima]

what version of node do you use?

[davyvanlaere]

v0.12.0

[vladima]

can you try to upgrade to node 5 and see if you still see this issue?

[davyvanlaere]

Just checked with version 4.3.1 (LTS) and 5.7.0 (stable), problem is gone. I apparently had an ancient node version ...

While running tsc, the process still peaks to 800Mb though (seems alot for such a small workload?)

[vladima]

recent version of rxjs have added more complex type definitions so analyzing them takes lots of time\memory - we already have an issue that tracks it.

[davyvanlaere]

Darn ... the repo builds, but the project it was distilled from still explodes. I'll see if i can isolate the problem again.

[vladima]

Can you share the actual code so we can be sure that root problem is addressed? We can sign an NDA if necessary.

[davyvanlaere]

NDA is not necessary, but i prefer not to share it publicly.

[vladima]

Can you send it to vladima at microsoft.com?

[davyvanlaere]

Sent!

[msklvsk]

Same here, importing and using {Observable} from 'rxjs/Observable' hangs compilation of an angular2 app since rxjs 5.0.0-beta.2

[msklvsk]

(present in TS 1.8.9, node 5.9.0)

[vladima]

this is one of a few similar issues that were reported recently (i.e. #7460 and #7344) that originate from the fact that type declarations in rxjs-5.0.0-beta.2 got more complicated and compiler spends lots of time exploring them. This is one of downsides of structural type system - in order to prove that two types are related their whole structure must be examined. We can short-circuit in a few places (#7474) but in general this problem is pretty hard to solve. Luckily it can be addressed on the consumer side - we are following up with RxJS folks to add a fix that should improve the situation (ReactiveX/rxjs#1475)

[msklvsk]

I forgot to mention that the hang happens on watch-triggered recompile. Initial build succeeds though (~2 sec slower than usual but still succeeds). Is it a known issue or should I post new one concerning successful initial but failed incremental?

[vladima]

we've seen the similar issue before due to significant increase of memory during type relation check - it was resolved after I switched to RxJS version that included ReactiveX/rxjs#1475. Given that this PR is already merged in master ( 👏 ) you can try to build RxJS from master and see if it will help in your case. If issue still exist I'd be very curious if I can somehow get your project for repro to make sure that problem is addressed.

[mhegazy]

Updating to latest RxJS beta should address the issue. please reopen if the issue persists on newer versions of the framework.