is `GlobalScope` considered bad practice what is the specifi

Question

is `GlobalScope` considered bad practice what is the specific use case of it

gildor · Answer

When you really need global background state

gildor · Answer

Also for some adapters like for RxJava where you just want to delegate lifecycle management to subscriber

uhe · Answer

I really really don t think that using `GlobalScope` can always be considered bad practice

gildor · Answer

In most of cases it is

uhe · Answer

Is there a list of most of cases that I can check

gildor · Answer

just checking with our code base

uhe · Answer

I m asking this because most of the official examples that I have seen that advocate structured concurrency are tied to very specific use cases

gildor · Answer

I disagree

gildor · Answer

why they are specific

gildor · Answer

we now even injecting scope for top level global tasks which before were just global now has user session lifecycle

uhe · Answer

Specific in a way that prevents me from applying them in my contexts

uhe · Answer

Maybe that s just me though Sorry for derailing the discussion

gildor · Answer

What is your context Do you have an example

Antanas A. · Answer

It s considered bad practices because you cannot control that run in your test suites

Antanas A. · Answer

Haven t worked for us and every time we ve converted `GlobalScope launch` call into explicitlyPassedScope launch

Antanas A. · Answer

for example you cannot simulate time line in tests so code with some `delay ` calls cannot be tested fast

uhe · Answer

Can t you use <https github com Kotlin kotlinx coroutines tree master kotlinx coroutines test testing launch or async with delay> for that haven t tested it myself

uhe · Answer

Also you can still change the dispatcher job that you pass to `GlobalScope launch` in your tests

gildor · Answer

gt It s considered bad practices because you cannot control that run in your test suites I think it s wrong assumption It s bad practice because it s global background job whicch should be explicitly handled and in most cases it may be avoided And yeah test such side effects is also probably bad practice by itself better to test suspend functions

gildor · Answer

gt for example you cannot simulate time line in tests so code with some `delay ` calls cannot be tested fast You still can inject custom context to launch it has nothing to do with GlobalScope it s the same as with any other scope

streetsofboston · Answer

For testability we inject the scope on which an instance s launches run at runtime That allows us to inject a testCoroutineScope when running unit tests Even during injection we don t often inject GlobalScope and inject CoroutineScope someJob + someDispatcher instead