hanging GETINFO

[meejah]

Fixes #389

[coveralls]

coverage: 99.574%. remained the same when pulling caf0b38 on 389.hang-getinfo into c0c98ff on main.

[meejah]

@hellais if it's easy to test, would appreciate your feedback as to whether this fixes your issue?

[hellais]

I have tested this PR and am happy to confirm it fixes the issue reported in #389.

I will run this branch against the full exit list and once it's done report back if it's causing any issues due to maximum length being reached.

Question ❓ : What will happen if there is a descriptor line which is longer than 2^20? Will it produce an error that hints at the fact this is the reason for the failure?

[meejah]

Question ❓ : What will happen if there is a descriptor line which is longer than 2^20? Will it produce an error that hints at the fact this is the reason for the failure?

No, it'll nuke the connection like it does now :(
Not ideal, obviously --- I've filed #391 to remind future humans to produce a better message.

Another solution would be to have "no limit". Twisted's implementation doesn't allow for this directly, but either re-writing or "more overriding" should be able to remove it (or set the limit to MAX_INT). There'd still be a limit of course (available memory).