Resuming newly stopped thread crashes Kotlin Debug Adapter

[nela]

Hello,

Thanks for a great plugin!

Problem

I am trying to get nvim-dap to work with Kotlin Debug Adapter and am experiencing issues when setting breakpoints and stepping over/ continuing these. The errors I get is the same as described in an earlier issue. At first, I also thought that this is an issue with the Kotlin Debug Adapter and have posted an issue there going into more detail.

However, after some digging around I think the issue indeed is with the nvim-dap. Going through the logs I've found this relevant snippet.

[ DEBUG ] 2022-11-01T19:05:46Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:575 ]	"Received stopped event, but main is already stopped. Resuming newly stopped thread. To disable this set the `auto_continue_if_many_stopped` option to false."

[ DEBUG ] 2022-11-01T19:03:08Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:843 ]	{
  body = {
    stackFrames = { {
        column = 1,
        id = 2,
        line = 21,
        name = "parsedResponse",
        source = {
          name = "Repository.kt",
          path = "/home/nela/projects/ktest/app/src/main/kotlin/ktest/Repository.kt"
        }
      }, {
        column = 1,
        id = 3,
        line = 10,
        name = "makeRequest",
        source = {
          name = "Repository.kt",
          path = "/home/nela/projects/ktest/app/src/main/kotlin/ktest/Repository.kt"
        }
      }, {
        column = 1,
        id = 4,
        line = 16,
        name = "main",
        source = {
          name = "App.kt",
          path = "/home/nela/projects/ktest/app/src/main/kotlin/ktest/App.kt"
        }
      }, {
        column = 1,
        id = 5,
        line = -1,
        name = "main",
        source = {
          name = "App.kt",
          path = "/home/nela/projects/ktest/app/src/main/kotlin/ktest/App.kt"
        }
      } }
  },
  command = "stackTrace",
  request_seq = 10,
  seq = 28,
  success = true,
  type = "response"
}
[ DEBUG ] 2022-11-01T19:03:08Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:1356 ]	"request"	{
  arguments = {
    frameId = 2
  },
  command = "scopes",
  seq = 12,
  type = "request"
}
[ DEBUG ] 2022-11-01T19:03:08Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:843 ]	{
  body = {
    allThreadsContinued = false
  },
  command = "continue",
  request_seq = 11,
  seq = 29,
  success = true,
  type = "response"
}
[ DEBUG ] 2022-11-01T19:03:08Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:843 ]	{
  body = {
    reason = "exited",
    threadId = 1
  },
  event = "thread",
  seq = 31,
  type = "event"
}

... [stdout]...

[ ERROR ] 2022-11-01T19:03:08Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:1169 ]	"stderr"	{
  command = "/home/nela/.local/repositories/kotlin-debug-adapter/adapter/build/install/adapter/bin/kotlin-debug-adapter",
  options = {
    disconnect_timeout_sec = 15,
    initialize_timeout_sec = 15
  },
  type = "executable"
}	"Nov 01, 2022 7:03:08 PM org.eclipse.lsp4j.jsonrpc.RemoteEndpoint fallbackResponseError\nSEVERE: Internal error: java.lang.reflect.InvocationTargetException\njava.lang.RuntimeException: java.lang.reflect.InvocationTargetException\n\tat org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.lambda$null$0(GenericEndpoint.java:67)\n\tat org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.request(GenericEndpoint.java:120)\n\tat org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.handleRequest(RemoteEndpoint.java:261)\n\tat org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.consume(RemoteEndpoint.java:190)\n\tat org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.handleMessage(StreamMessageProducer.java:194)\n\tat org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.listen(StreamMessageProducer.java:94)\n\tat org.eclipse.lsp4j.jsonrpc.json.ConcurrentMessageProcessor.run(ConcurrentMessageProcessor.java:113)\n\tat java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)\n\tat java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)\n\tat java.base/java.lang.Thread.run(Thread.java:833)\nCaused by: java.lang.reflect.InvocationTargetException\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)\n\tat java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n\tat java.base/java.lang.reflect.Method.invoke(Method.java:568)\n\tat org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.lambda$null$0(GenericEndpoint.java:65)\n\t... 11 more\nCaused by: org.javacs.ktda.util.KotlinDAException: Could not find stackTrace with ID 2\n\tat org.javacs.ktda.adapter.KotlinDebugAdapter.scopes(KotlinDebugAdapter.kt:361)\n\t... 16 more\n\n"

Here the nvim-dap continues execution through the stackFrame ID 2, and when I execute the command to continue or step over the Kotlin Debugger throws the error not being able to find stackTrace widht ID 2. The main clue is the message Received stopped event, but main is already stopped. Resuming newly stopped thread. To disable this set the auto_continue_if_many_stopped option to false.
I've tried setting auto_continue_if_many_stopped = false everywhere in my config, to no avail. Then I tried removing these lines of code, setting only should_jump = false and then the debugging finally worked properly.

Questions

So, to the core of the post.

1. How to properly set auto_continue_if_many_stopped = false in the configuration?. The code gets the default settings using this function which, according to my understanding outputs the name of adapter configuration - 'kotlin' in my case.
2. This option is not covered anywhere in the documentation - I think many users would appreciate information regarding this.
3. Out of curiosity, why is this the default behaviour? Why is the process that is delibaretly paused, resumed?

Config

For completion here is my nvim-dap kotlin config. Hardcoded paths and mainClass for testing purposes.

local ok, dap = pcall(require, 'dap')
if not ok then return end


dap.adapters.kotlin = {
    type = 'executable',
    command = os.getenv('REPO_HOME') .. '/kotlin-debug-adapter/adapter/build/install/adapter/bin/kotlin-debug-adapter',
    options = {
        initialize_timeout_sec = 15,
        disconnect_timeout_sec = 15,
        auto_continue_if_many_stopped = false,
    },
}

dap.configurations.kotlin = {
    {
        type = 'kotlin',
        request = 'launch',
        name = "Kotlin",
        projectRoot = '/home/nela/projects/ktest/app',
        mainClass = 'ktest.AppKt',
    }
}

[mfussenegger]

auto_continue_if_many_stopped must be set in the defaults table. Either:

require('dap').defaults.fallback.auto_continue_if_many_stopped = false

If you want to set it for all debug adapters, or to set it only for kotlin:

require('dap').defaults.kotlin.auto_continue_if_many_stopped = false

You're right, this setting should be documented.

It's only auto-resumed if another thread is already stopped. The idea is that if you're debugging a multithreaded application you'll have only one thread stop at the current breakpoint while other threads will continue processing.

The reason this is the default is mainly because a) it was initially easier to implement and b) I found this behavior to be more useful.

But this should never make the debugging not work, so there seems to be an issue either on the kotlin side or on the nvim-dap side.

Could you share a log where the communication before the "Received stopped event, but main is already stopped. Resuming newly stopped thread. To disable this set the auto_continue_if_many_stopped option to false." message is also included?

[nela]

Thanks for the explanation! Setting the auto_continue_if_many_stopped property as you specified solved the problem.

Here are the logs before the "Resuming newly stopped...". I've tried to include the spawning of threads. Here is a gist of the entire log.

[ DEBUG ] 2022-11-05T11:32:30Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    category = "console",
    output = "[INFO] async1    Starting JVM debug session with main class ktest.AppKt\n"
  },
  event = "output",
  seq = 13,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:30Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  command = "launch",
  request_seq = 2,
  seq = 14,
  success = true,
  type = "response"
}
[ DEBUG ] 2022-11-05T11:32:30Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "started",
    threadId = 493
  },
  event = "thread",
  seq = 15,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:30Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    category = "stdout",
    output = "Hello World!\n"
  },
  event = "output",
  seq = 16,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "started",
    threadId = 2529
  },
  event = "thread",
  seq = 17,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "started",
    threadId = 2545
  },
  event = "thread",
  seq = 18,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "started",
    threadId = 2546
  },
  event = "thread",
  seq = 19,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "started",
    threadId = 2576
  },
  event = "thread",
  seq = 20,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "started",
    threadId = 2577
  },
  event = "thread",
  seq = 21,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "breakpoint",
    threadId = 1
  },
  event = "stopped",
  seq = 22,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:1351 ]	"request"	{
  command = "threads",
  seq = 8,
  type = "request"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "breakpoint",
    threadId = 1
  },
  event = "stopped",
  seq = 23,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:1351 ]	"request"	{
  command = "threads",
  seq = 9,
  type = "request"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    threads = { {
        id = 1,
        name = "main"
      }, {
        id = 2,
        name = "Reference Handler"
      }, {
        id = 3,
        name = "Finalizer"
      }, {
        id = 4,
        name = "Signal Dispatcher"
      }, {
        id = 5,
        name = "Notification Thread"
      }, {
        id = 493,
        name = "Common-Cleaner"
      }, {
        id = 2529,
        name = "OkHttp frost.met.no"
      }, {
        id = 2545,
        name = "OkHttp ConnectionPool"
      }, {
        id = 2546,
        name = "OkHttp frost.met.no Writer"
      }, {
        id = 2576,
        name = "OkHttp Http2Connection"
      }, {
        id = 2577,
        name = "Okio Watchdog"
      } }
  },
  command = "threads",
  request_seq = 8,
  seq = 24,
  success = true,
  type = "response"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:1351 ]	"request"	{
  arguments = {
    threadId = 1
  },
  command = "stackTrace",
  seq = 10,
  type = "request"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    threads = { {
        id = 1,
        name = "main"
      }, {
        id = 2,
        name = "Reference Handler"
      }, {
        id = 3,
        name = "Finalizer"
      }, {
        id = 4,
        name = "Signal Dispatcher"
      }, {
        id = 5,
        name = "Notification Thread"
      }, {
        id = 493,
        name = "Common-Cleaner"
      }, {
        id = 2529,
        name = "OkHttp frost.met.no"
      }, {
        id = 2545,
        name = "OkHttp ConnectionPool"
      }, {
        id = 2546,
        name = "OkHttp frost.met.no Writer"
      }, {
        id = 2576,
        name = "OkHttp Http2Connection"
      }, {
        id = 2577,
        name = "Okio Watchdog"
      } }
  },
  command = "threads",
  request_seq = 9,
  seq = 25,
  success = true,
  type = "response"
}

[mfussenegger]

What's odd is that there are two stopped events for the same thread without any continue/step in-between:

[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "breakpoint",
    threadId = 1
  },
  event = "stopped",
  seq = 22,
  type = "event"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:1351 ]	"request"	{
  command = "threads",
  seq = 8,
  type = "request"
}
[ DEBUG ] 2022-11-05T11:32:31Z+0100 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:838 ]	{
  body = {
    reason = "breakpoint",
    threadId = 1
  },
  event = "stopped",
  seq = 23,
  type = "event"
}

This may indicate a problem on the debug adapter side?

[nela]

There may be a problem with the debugger adapter, I am not entirely sure. I have posted and issue and linked to this discussion, so hopefully the maintainers will have look. Your first response however, fixed my immediate issue so I will mark it as the accepted answer!