Reading user input loops the program without debugging capability

[aleksandr-shevchenko]

package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
    reader := bufio.NewScanner(os.Stdin)

    for reader.Scan() {
        s := reader.Text()
        if s == "" {
            break
        }
        fmt.Println(s)
    }
}

debug console:
Starting: d:\Go\bin\dlv-dap.exe dap --listen=127.0.0.1:59530
DAP server listening at: 127.0.0.1:59530
123
Unable to process evaluate: debuggee is running
eee
Unable to process evaluate: debuggee is running
-- I press Enter only --
Unable to process evaluate: debuggee is running
-- stop execute by Shift-F5 --
Detaching and terminating target process
dlv dap (1060) exited with code: 0

Stop program only by Shift-F5.
Debug not working.

Golang, VSCode and go plugin latest version.
OS Win10 Pro

[polinasok]

Debug Console is not designed for entering stdin. It's not a terminal, where your process is foregrounded and can read stdin. It's a REPL environment for evaluating expressions, which is only possible when the target is not running (otherwise you get an error message).

Here is what you can do instead:

1. Run dlv server in a separate server terminal, where it will foreground your process, so you can enter stdin into that terminal.

$ dlv-dap dap --listen=:54321
DAP server listening at: [::]:54321
debugserver-@(#)PROGRAM:LLDB  PROJECT:lldb-1205.0.27
 for x86_64.
Got a connection, launched process /Users/polina/delve/__debug_bin (pid = 8737).
123
read from stdin: 123

Exiting.

2. Use launch.json configuration to connect to this server. Essentially this means taking any existing launch configuration that already works for you and adding debugServer to it to tell it use an external server instead of launching one for you inside of vscode extension. For example,

{
            "name": "Launch file via external dlv-dap",
            "type": "go",
            "request": "launch",
            "mode":"debug",
            "program": "${file}",
            "debugServer":54321, 
}

We know this is not ideal. Please see this issue for what else we are exploring in the long term: #124 (comment).

[aleksandr-shevchenko]

Thanks!