tools: warn users if go.goroot is configured - it mutates GOROOT env var

[TheJonRobinson]

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 go1.13.4 darwin/amd64
• Run gopls -v version to get version of Gopls from the VS Code integrated terminal.
  • command not found: gopls
• Run code -v or code-insiders -v to get version of VS Code or VS Code Insiders.
  • 1.56.1 e713fe9b05fc24facbec8f34fb1017133858842b x64
• Check your installed extensions to get the version of the VS Code Go extension
  • 0.25.0
• Run Ctrl+Shift+P (Cmd+Shift+P on Mac OS) > Go: Locate Configured Go Tools command.

Checking configured tools....
GOBIN: undefined
toolsGopath: 
gopath: undefined
GOROOT: /usr/local/go/bin/go
PATH: /Users/jonrobinson/google-cloud-sdk/bin://bin:/Users/jonrobinson/.nvm/versions/node/v12.16.1/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/go/bin

failed to run "/usr/local/go/bin/go version": Error: Command failed: /usr/local/go/bin/go version
go: cannot find GOROOT directory: /usr/local/go/bin/go
 cwd: /Volumes/Development/game-pizzarush

Share the Go related settings you have added/edited

Run Preferences: Open Settings (JSON) command to open your settings.json file.
Share all the settings with the go. or ["go"] or gopls prefixes.

    "go.formatTool": "goimports",
    "[go]": {
        "editor.insertSpaces": false,
        "editor.formatOnSave": true,
        "editor.codeActionsOnSave": {
            "source.organizeImports": true
        }
    },
    "go.useLanguageServer": true,
    "go.toolsManagement.autoUpdate": true,

Describe the bug

A clear and concise description of what the bug.

We have been happily using 0.24.2 on the extension, but after the update happened to 0.25.0, we get the following pop-up when opening the VS-Code project:

Failed to run '/usr/local/go/bin/go env. The config change may not be applied correctly.
Source: Go (Extension)

Also, in the OUTPUT window:

Failed to run '/usr/local/go/bin/go env' (cwd: /Volumes/Development/game-pizzarush): Error: Command failed: /usr/local/go/bin/go env -json GOPATH GOROOT GOPROXY GOBIN GOMODCACHE
go: cannot find GOROOT directory: /usr/local/go/bin/go

go: cannot find GOROOT directory: /usr/local/go/bin/go

After this, gopls is not present/working and the go environment seems somewhat broken.

NB If we revert the extension back to the previous one, the problems go away.

A clear and concise description of what you expected to happen.

We'd expect the behaviour to remain as before the 0.25.0 update.

Steps to reproduce the behavior:

1. After the Go extension has updated to 0.25.0
2. Open the workspace in VS-Code
3. See error

[hyangah]

Thanks for the report @TheJonRobinson
It's probably related to the commit but I thought that should change behavior only if go.goroot setting is used. It doesn't seem like you are using it though. Is the workspace setting empty?
(Preferences: Open Workspace Settings (JSON))

[bestbeforetoday]

I also started seeing this issue with the update to v0.25.0 of the Go extension. I checked my VS Code settings and there was a go.goroot entry there. This isn't something I recall ever setting, and isn't something that was causing an issue before. Removing the go.goroot entry in my VS Code settings seems to have resolved the startup error.

[TheJonRobinson]

Ah - so yes, our project does have a workspace, which does indeed set `go.goroot` - I missed that because I just used the Preferences: Open Settings (JSON) which doesn’t include those. Removing the setting altogether resolves the problem though, as I just noticed @bestbeforetoday commented. Similarly, that setting has been there since I created the project, and I can’t remember whether it was automagically set or I did but it certainly was benign before 0.25.0

[hyangah]

Long story - For many years go.goroot was used to set the GOROOT environment variable. Setting GOROOT environment variable is no longer recommended and in fact, probably against the best practice. Modern versions of Go find the right GOROOT by themselves when GOROOT isn't set. So, we cleaned up its behavior as part of #146 and made that not to set GOROOT environment variable any more.

Unfortunately, there are still some popular version management tools that were written long ago and somehow depends on setting GOROOT environment variable to operate correctly. And there were users who want to unset/override GOROOT environment variable set in their environment. We received multiple requests to bring back the old behavior (#776 for example). We considered completely deprecating go.goroot and recommending users to use go.toolsEnvVars when they need to modify with the go's environment variables. But there was usability & security implication. So, instead we brought back go.goroot's old behavior.

Most users shouldn't set go.goroot setting at all.

We can add extra warnings when go.goroot setting is detected.

[joelft]

Just for the sake of thoroughness for any googlers landing here, make sure to also check WSL settings if using VS Code Remote to program in WSL.

In my case, that's where the stale go.root setting was located.

[gopherbot]

Change https://golang.org/cl/320429 mentions this issue: src/goMain: warn users if go.goroot is set

[gopherbot]

Change https://golang.org/cl/320549 mentions this issue: [release] src/goMain: warn users if go.goroot is set