debug: connecting to dlv-dap results in connection error

[suzmue]

What version of Go, VS Code & VS Code Go extension are you using?

• Run go version to get version of Go from the VS Code integrated terminal.
  • go version go1.16 darwin/amd64
• Run code -v or code-insiders -v to get version of VS Code or VS Code Insiders.
  • 1.53.2
• Check your installed extensions to get the version of the VS Code Go extension
  • Go Nightly

Describe the bug

{
            "name": "Launch Program",
            "type": "go",
            "request": "launch",
            "mode": "debug",
            "program": "${workspaceFolder}",
            "debugAdapter": "dlv-dap"
 }

Steps to reproduce the behavior:

1. Reinstall dlv
2. Click on 'Launch Program'
3. See error

This appears to be a timing related issue, since it does not happen often. This needs a better error message and/or a second attempt to connect.

[polinasok]

This happens when the server is not up and ready to listen. Do we have a sufficient delay in the factory? I think there used to be a start-up delay in the old adapter as well.

[polinasok]

The error message is coming from the editor. I don't know how to control it.

[suzmue]

There was a delay but it was not sufficient. Once @hyangah's change for redirecting stdout and stderr from dlv dap is in, I have a change that will wait for the "DAP serving listening at" message before returning the server info to vscode.

[gopherbot]

Change https://golang.org/cl/300071 mentions this issue: src/goDebugFactory: wait for dlv dap server to start in factory

[gopherbot]

Change https://golang.org/cl/300609 mentions this issue: [release] src/goDebugFactory: wait for dlv dap server to start in factory