Fix potentially undefined httpModule

[deammer]

Fixes #4036

• If you've added code that should be tested, please add tests.
• Ensure your code lints and the test suite passes (yarn lint) & (yarn test).

[kamilogorek]

Can you share a stacktrace of the error? I'd like to understand how it can happen in the first place.

[deammer]

Hey @kamilogorek, I posted the stacktrace in #4036. I don't know if anything below the second line is very helpful though. For what it's worth, the issue occurred 100% of the time after we upgraded to 6.13.2, and it broke our product for 2 hours. After we went back to 6.9.0, things worked perfectly again.

[kamilogorek]

I will merge this, as it's a trivial fix, however, we should better understand what's going on here.
Webckets (which this issue is related to) do not have a default agent so I'd understand if it would break on globalAgent.protocol access, but in this case, there are some API overrides shenanigans going on.

this should always refer to the http/s module, and we know for sure it exists, because when we wrap it, we do check for the method existence first in fill function:

const httpModule = require('http');
fill(httpModule, 'get', wrappedHandlerMaker);
fill(httpModule, 'request', wrappedHandlerMaker);

To fill it, it has to exist in the first place.

Is there a chance that you could somehow isolate this issue so we can correctly test it and not break like that in the future?

[deammer]

Thank you for merging the fix @kamilogorek. I've added a task to our backlog to isolate this issue and get back to you.