feat(angular_devkit): stop blocking karma after compilation error

[nicojs]

This PR removes the blocking of karma in case of compilation errors. This will not influence regular developer workflows (with ng test and ng test --single-run), but does help plugin creators relying on karma run functionality (with singleRun: false and watch: false).

Fixes #11170

[filipesilva]

LGTM, thanks for improving this!

By the way, have you found a way to exit karma gracefully in a programmatic way? I haven't really found one that doesn't call process.exit.

[nicojs]

By the way, have you found a way to exit karma gracefully in a programmatic way? I haven't really found one that doesn't call process.exit.

No, that isn't possible (that I know of). The only way documented way to stop karma is using karma.stopper.stop(options, [callback=process.exit]). This command sends an HTTP request to the karma server (for example: HTTP GET http://localhost:3456/stop).

The callback parameter defaults to process.exit so you might think that you can override that behavior. However, this is only the callback received by the caller. If you look at the middleware handling the http request, you can see that it always calls process.kill:
https://github.com/karma-runner/karma/blob/e8ca4ecefe92bd28494467503b09f3588b787cf7/lib/middleware/stopper.js#L13

In most cases (stryker, ng test, ...) the process hosting the karma server is also the process that would be sending the stop command, so the callback isn't even executed in those cases, as process.kill already happened. We designed Stryker around this by sand boxing test runners into separate processes.

Karma deserves some more love from the open source community. Unfortunately, I don't have the time for it.

Btw, when is the next release of the Angular CLI? I can't wait to try it out with Stryker.

[filipesilva]

Yeah that's the conclusion I got to as well, just wanted the double check if I was missing anything.

Next release of the CLI and devkit packages should be next week.

[nicojs]

Next release of the CLI and devkit packages should be next week.

I see there is a new release:

However, the new code seems to be absent

@filipesilva Did something go wrong during release?

[nicojs]

I see. It is released under the @next tag. Thanks for pointing that out to me @filipesilva, works like a charm!

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