redhat-developer / redhat-developer/lsp4ij

Golang DAP: `fmt.Println()`/`fmt.Println("")`/`fmt.Print("\n")` are not displayed in the DAP output

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#1,651 6 comments 0 reactions 1 assignee View on GitHub

@angelozerr is already working on this.

Since Aug 31, 2026.

bug
Dominant language
Java
Stars
344
Forks
113
Avg merge
5h 22m
Merged PRs (30d)
15

Description

Golang DAP: fmt.Println()/fmt.Println("")/fmt.Print("\n") are not displayed in the DAP output

package main

import (
	"fmt"
)

func main() {
	fmt.Println("a")
	fmt.Println() // not displayed in DAP output
	fmt.Println("b")
	fmt.Println("") // not displayed in DAP output
	fmt.Println("c")
	fmt.Print("\n") // not displayed in DAP output
	fmt.Println("d")
}
Image

Dap run log

dlv dap
Launching 'test.go' with 'Go - Delve'
DAP server listening at: 127.0.0.1:3084
[Trace - 12:52:09] Sending request 'initialize - (1)'.
Params: {
  "clientID": "lsp4ij.debug",
  "clientName": "IntelliJ IDEA 2026.2.1",
  "adapterID": "go",
  "linesStartAt1": true,
  "columnsStartAt1": true,
  "pathFormat": "path",
  "supportsVariableType": true,
  "supportsVariablePaging": false,
  "supportsRunInTerminalRequest": true,
  "supportsStartDebuggingRequest": true
}


[Trace - 12:52:09] Received response 'initialize - (1)' in 4ms.
Result: {
  "supportsConfigurationDoneRequest": true,
  "supportsFunctionBreakpoints": true,
  "supportsConditionalBreakpoints": true,
  "supportsHitConditionalBreakpoints": true,
  "supportsEvaluateForHovers": true,
  "exceptionBreakpointFilters": [
    {
      "filter": "unrecovered-panic",
      "label": "Unrecovered Panics",
      "default": true
    },
    {
      "filter": "runtime-fatal-throw",
      "label": "Fatal Throws",
      "default": true
    }
  ],
  "supportsSetVariable": true,
  "supportsRestartRequest": true,
  "supportsExceptionInfoRequest": true,
  "supportsDelayedStackTraceLoading": true,
  "supportsLogPoints": true,
  "supportsReadMemoryRequest": true,
  "supportsDisassembleRequest": true,
  "supportsClipboardContext": true,
  "supportsSteppingGranularity": true,
  "supportsInstructionBreakpoints": true
}


[Trace - 12:52:09] Sending request 'launch - (2)'.
Params: {
  "name": "Launch Go file",
  "request": "launch",
  "cwd": "E:/vcsProjects/wiki",
  "program": "E:\\vcsProjects\\wiki\\test\\test.go",
  "type": "go",
  "noDebug": true
}


[Trace - 12:52:09] Received notification 'output'
Params: {
  "category": "stdout",
  "output": "Building E:\\vcsProjects\\wiki\\test\\test.go"
}


Building E:\vcsProjects\wiki\test\test.go
[Trace - 12:52:10] Received response 'launch - (2)' in 1388ms.
No response returned.


a
b
c
d
[Trace - 12:52:10] Received notification 'output'
Params: {
  "category": "console",
  "output": "Process 20252 has exited with status 0\n"
}


Process 20252 has exited with status 0
[Trace - 12:52:10] Received notification 'terminated'
Params: {}


[Trace - 12:52:10] Sending request 'disconnect - (3)'.
Params: {}


Disconnected successfully from the debug server.
[Trace - 12:52:10] Received response 'disconnect - (3)' in 1ms.
No response returned.



Process finished with exit code 0
Image Image

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