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hey all - I have a bizarre situation that I'm tryi...
# coroutines
m
hey all - I have a bizarre situation that I'm trying to wrap my head around.. I've got a production JVM application running coroutines on Spring Webflux. A suspend function all of a sudden started exploding with
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java.lang.NullPointerException: Cannot invoke "kotlin.coroutines.Continuation.getContext()" because "$completion" is null
with the offending stack trace (which unfortunately I can't share) pointed to a simple 
currentCoroutineContext()
, to a generic code that have been running in production for quite some time without issues:
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suspend fun <A> withObservability(fx: suspend ReactiveLogger.() -> A): A {
  currentCoroutineContext() // blew up here
  ...
}
Also it's not deterministic: it doesn't happen to anywhere else in the codebase but one very specific endpoint. We've been using this function literally everywhere in the code and has been running rock solid for at least the last ~4 years. This is a bit over my head and I'm trying to understand how can I debug this.. why would the completion be null? also maybe a red herring but we started seeing this after we upgraded Kotlin from 1.9.21 to 1.9.22 kotlinx.coroutines version 1.7.3 kotlin version 1.9.22 java 17.0.9
a
Very strange. The only thing that comes to my mind is, what’s the reason for using 
currentCoroutineContext()
over 
coroutineContext
here, and are you sure it’s what you want?
r
It’s difficult to determine the reason without the code. But if your stack trace is useless, may be https://github.com/Anamorphosee/stacktrace-decoroutinator could help to localize the problem
m
It's quite bizarre. I somehow managed to resolve it by moving the code to a private function... without any modification.
my colleague's intellij apparently didn't show it but my intellij also showed a weird error during compilation
managed to reproduce it in the old branch. Build in CI passes, but compilation locally didn't work. And I didn't remember enabling K2..
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org.jetbrains.kotlin.backend.common.BackendException: Backend Internal error: Exception during IR lowering
File being compiled: /Users/myuwono/Development/path/to/File.kt
The root cause java.lang.AssertionError was thrown at: org.jetbrains.kotlin.backend.jvm.lower.AddContinuationLoweringKt.retargetToSuspendView(AddContinuationLowering.kt:500)
	at org.jetbrains.kotlin.backend.common.CodegenUtil.reportBackendException(CodegenUtil.kt:253)
	at org.jetbrains.kotlin.backend.common.CodegenUtil.reportBackendException$default(CodegenUtil.kt:237)
	at org.jetbrains.kotlin.backend.common.phaser.PerformByIrFilePhase.invokeSequential(performByIrFile.kt:65)
	at org.jetbrains.kotlin.backend.common.phaser.PerformByIrFilePhase.invoke(performByIrFile.kt:52)
	at org.jetbrains.kotlin.backend.common.phaser.PerformByIrFilePhase.invoke(performByIrFile.kt:38)
	at org.jetbrains.kotlin.backend.common.phaser.NamedCompilerPhase.phaseBody(CompilerPhase.kt:147)
	at org.jetbrains.kotlin.backend.common.phaser.AbstractNamedCompilerPhase.invoke(CompilerPhase.kt:94)
	at org.jetbrains.kotlin.backend.common.phaser.CompositePhase.invoke(PhaseBuilders.kt:29)
	at org.jetbrains.kotlin.backend.common.phaser.CompositePhase.invoke(PhaseBuilders.kt:16)
	at org.jetbrains.kotlin.backend.common.phaser.NamedCompilerPhase.phaseBody(CompilerPhase.kt:147)
	at org.jetbrains.kotlin.backend.common.phaser.AbstractNamedCompilerPhase.invoke(CompilerPhase.kt:94)
	at org.jetbrains.kotlin.backend.common.phaser.CompilerPhaseKt.invokeToplevel(CompilerPhase.kt:43)
	at org.jetbrains.kotlin.backend.jvm.JvmIrCodegenFactory.invokeLowerings(JvmIrCodegenFactory.kt:348)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.runLowerings(KotlinToJVMBytecodeCompiler.kt:330)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli(KotlinToJVMBytecodeCompiler.kt:114)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli$default(KotlinToJVMBytecodeCompiler.kt:43)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:165)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:50)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:104)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:48)
	at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:101)
	at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:463)
	at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:62)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.doCompile(IncrementalCompilerRunner.kt:477)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compileImpl(IncrementalCompilerRunner.kt:400)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.tryCompileIncrementally$lambda$6$compile(IncrementalCompilerRunner.kt:231)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.tryCompileIncrementally(IncrementalCompilerRunner.kt:247)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compile(IncrementalCompilerRunner.kt:116)
	at org.jetbrains.kotlin.daemon.CompileServiceImplBase.execIncrementalCompiler(CompileServiceImpl.kt:657)
	at org.jetbrains.kotlin.daemon.CompileServiceImplBase.access$execIncrementalCompiler(CompileServiceImpl.kt:105)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:1624)
	at jdk.internal.reflect.GeneratedMethodAccessor94.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at java.rmi/sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:360)
	at java.rmi/sun.rmi.transport.Transport$1.run(Transport.java:200)
	at java.rmi/sun.rmi.transport.Transport$1.run(Transport.java:197)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:712)
	at java.rmi/sun.rmi.transport.Transport.serviceCall(Transport.java:196)
	at java.rmi/sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:587)
	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:828)
	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:705)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:704)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:833)
probably I'll cross post this in K2? It's pretty bizzare
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cross post @AdamW @reformator confirmed was a compiler bug.. I'm trying to get a code to reproduce this https://kotlinlang.slack.com/archives/C03PK0PE257/p1704916217082399?thread_ts=1704872237.198799&amp;cid=C03PK0PE257
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