How can I catch an exception in Kotlin coroutine when I am awaiting it in another function?
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Sorry for the vague title, couldn't come up with something better.
So I read this article and wanted to do the same. problem is that I can't do try { promise... } catch (e) { } cause the error gets swallowed. I can catch the error where I await it, but I don't want that.
and my code looks like this:
typealias Promise<T> = Deferred<T>
fun <T, R> Promise<T>.then(handler: (T) -> R): Promise<R> = GlobalScope.async(Dispatchers.Main) {
// using try/catch here works but I don't want it here.
val result = this@then.await()
handler.invoke(result)
}
object PromiseUtil {
fun <T> promisify(block: suspend CoroutineScope.() -> T): Promise<T> = GlobalScope.async { block.invoke(this) }
}
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
And I read this and this one too, but I want to somehow catch errors in the UI code, and don't want to use runBlocking { ... }.
Thanks.
android kotlin kotlinx.coroutines asked Jan 4 at 15:40
PooyaPooya
2928
add a comment |
Sorry for the vague title, couldn't come up with something better.
So I read this article and wanted to do the same. problem is that I can't do try { promise... } catch (e) { } cause the error gets swallowed. I can catch the error where I await it, but I don't want that.
and my code looks like this:
typealias Promise<T> = Deferred<T>
fun <T, R> Promise<T>.then(handler: (T) -> R): Promise<R> = GlobalScope.async(Dispatchers.Main) {
// using try/catch here works but I don't want it here.
val result = this@then.await()
handler.invoke(result)
}
object PromiseUtil {
fun <T> promisify(block: suspend CoroutineScope.() -> T): Promise<T> = GlobalScope.async { block.invoke(this) }
}
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
And I read this and this one too, but I want to somehow catch errors in the UI code, and don't want to use runBlocking { ... }.
Thanks.
android kotlin kotlinx.coroutines asked Jan 4 at 15:40
PooyaPooya
2928
On your UI I think you should use the other extensionsthenAsyncfor theawait()to be done correctly.
– shkschneider
Jan 4 at 15:53
@shkschneider tested that but it didn't work, and most of the time I don't have other asynchronous work to do after first one.
– Pooya
Jan 4 at 16:40
add a comment |
Sorry for the vague title, couldn't come up with something better.
So I read this article and wanted to do the same. problem is that I can't do try { promise... } catch (e) { } cause the error gets swallowed. I can catch the error where I await it, but I don't want that.
and my code looks like this:
typealias Promise<T> = Deferred<T>
fun <T, R> Promise<T>.then(handler: (T) -> R): Promise<R> = GlobalScope.async(Dispatchers.Main) {
// using try/catch here works but I don't want it here.
val result = this@then.await()
handler.invoke(result)
}
object PromiseUtil {
fun <T> promisify(block: suspend CoroutineScope.() -> T): Promise<T> = GlobalScope.async { block.invoke(this) }
}
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
And I read this and this one too, but I want to somehow catch errors in the UI code, and don't want to use runBlocking { ... }.
Thanks.
android kotlin kotlinx.coroutines asked Jan 4 at 15:40
PooyaPooya
2928
Sorry for the vague title, couldn't come up with something better.
So I read this article and wanted to do the same. problem is that I can't do try { promise... } catch (e) { } cause the error gets swallowed. I can catch the error where I await it, but I don't want that.
and my code looks like this:
typealias Promise<T> = Deferred<T>
fun <T, R> Promise<T>.then(handler: (T) -> R): Promise<R> = GlobalScope.async(Dispatchers.Main) {
// using try/catch here works but I don't want it here.
val result = this@then.await()
handler.invoke(result)
}
object PromiseUtil {
fun <T> promisify(block: suspend CoroutineScope.() -> T): Promise<T> = GlobalScope.async { block.invoke(this) }
}
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
And I read this and this one too, but I want to somehow catch errors in the UI code, and don't want to use runBlocking { ... }.
Thanks.
android kotlin kotlinx.coroutines android kotlin kotlinx.coroutines asked Jan 4 at 15:40
PooyaPooya
2928
asked Jan 4 at 15:40
PooyaPooya
2928
asked Jan 4 at 15:40
PooyaPooya
2928
asked Jan 4 at 15:40
PooyaPooya
2928
asked Jan 4 at 15:40
PooyaPooya
2928
2928
On your UI I think you should use the other extensionsthenAsyncfor theawait()to be done correctly.
– shkschneider
Jan 4 at 15:53
@shkschneider tested that but it didn't work, and most of the time I don't have other asynchronous work to do after first one.
– Pooya
Jan 4 at 16:40
add a comment |
On your UI I think you should use the other extensionsthenAsyncfor theawait()to be done correctly.
– shkschneider
Jan 4 at 15:53
@shkschneider tested that but it didn't work, and most of the time I don't have other asynchronous work to do after first one.
– Pooya
Jan 4 at 16:40
On your UI I think you should use the other extensions
thenAsync for the await() to be done correctly.– shkschneider
Jan 4 at 15:53
On your UI I think you should use the other extensions
thenAsync for the await() to be done correctly.– shkschneider
Jan 4 at 15:53
@shkschneider tested that but it didn't work, and most of the time I don't have other asynchronous work to do after first one.
– Pooya
Jan 4 at 16:40
@shkschneider tested that but it didn't work, and most of the time I don't have other asynchronous work to do after first one.
– Pooya
Jan 4 at 16:40
add a comment |
1 Answer
1
active
oldest
votes
The exception is never caught because it's never propagated by the async call. That happens when await() is called.
See coroutine exception handling.
Your code should be:
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await() // <--- added await() call
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
But this won't compile as await() is a suspending function. Therefore, it should be more like:
// somewhere in my UI testing it.
GlobalScope.launch(CoroutineExceptionHandler { coroutineContext, throwable ->
Log.d("ERROR_TAG", "It will catch error here")
throwable.printStackTrace()
}) {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await()
}
answered Jan 4 at 17:02
veritas1veritas1
4,65741632
Thanks. I thought awaiting it in "then function" will do that.
– Pooya
Jan 4 at 20:44
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The exception is never caught because it's never propagated by the async call. That happens when await() is called.
See coroutine exception handling.
Your code should be:
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await() // <--- added await() call
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
But this won't compile as await() is a suspending function. Therefore, it should be more like:
// somewhere in my UI testing it.
GlobalScope.launch(CoroutineExceptionHandler { coroutineContext, throwable ->
Log.d("ERROR_TAG", "It will catch error here")
throwable.printStackTrace()
}) {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await()
}
answered Jan 4 at 17:02
veritas1veritas1
4,65741632
Thanks. I thought awaiting it in "then function" will do that.
– Pooya
Jan 4 at 20:44
add a comment |
The exception is never caught because it's never propagated by the async call. That happens when await() is called.
See coroutine exception handling.
Your code should be:
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await() // <--- added await() call
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
But this won't compile as await() is a suspending function. Therefore, it should be more like:
// somewhere in my UI testing it.
GlobalScope.launch(CoroutineExceptionHandler { coroutineContext, throwable ->
Log.d("ERROR_TAG", "It will catch error here")
throwable.printStackTrace()
}) {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await()
}
answered Jan 4 at 17:02
veritas1veritas1
4,65741632
Thanks. I thought awaiting it in "then function" will do that.
– Pooya
Jan 4 at 20:44
add a comment |
The exception is never caught because it's never propagated by the async call. That happens when await() is called.
See coroutine exception handling.
Your code should be:
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await() // <--- added await() call
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
But this won't compile as await() is a suspending function. Therefore, it should be more like:
// somewhere in my UI testing it.
GlobalScope.launch(CoroutineExceptionHandler { coroutineContext, throwable ->
Log.d("ERROR_TAG", "It will catch error here")
throwable.printStackTrace()
}) {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await()
}
answered Jan 4 at 17:02
veritas1veritas1
4,65741632
The exception is never caught because it's never propagated by the async call. That happens when await() is called.
See coroutine exception handling.
Your code should be:
// somewhere in my UI testing it.
try {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await() // <--- added await() call
} catch (e: Exception) {
Log.d("ERROR_TAG", "It should catch the error here but it doesn't.")
}
But this won't compile as await() is a suspending function. Therefore, it should be more like:
// somewhere in my UI testing it.
GlobalScope.launch(CoroutineExceptionHandler { coroutineContext, throwable ->
Log.d("ERROR_TAG", "It will catch error here")
throwable.printStackTrace()
}) {
PromiseUtil.promisify { throw Exception("some exp") }
.then { Log.d("SOME_TAG", "Unreachable code.") }.await()
}
answered Jan 4 at 17:02
veritas1veritas1
4,65741632
answered Jan 4 at 17:02
veritas1veritas1
4,65741632
answered Jan 4 at 17:02
veritas1veritas1
4,65741632
answered Jan 4 at 17:02
veritas1veritas1
4,65741632
4,65741632
Thanks. I thought awaiting it in "then function" will do that.
– Pooya
Jan 4 at 20:44
add a comment |
Thanks. I thought awaiting it in "then function" will do that.
– Pooya
Jan 4 at 20:44
Thanks. I thought awaiting it in "then function" will do that.
– Pooya
Jan 4 at 20:44
Thanks. I thought awaiting it in "then function" will do that.
– Pooya
Jan 4 at 20:44
add a comment |
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On your UI I think you should use the other extensions
thenAsyncfor theawait()to be done correctly.– shkschneider
Jan 4 at 15:53
@shkschneider tested that but it didn't work, and most of the time I don't have other asynchronous work to do after first one.
– Pooya
Jan 4 at 16:40