Ubuntu images incorrectly set GOROOT

[FiloSottile]

Description

The Ubuntu images should not be setting the GOROOT environment variable.

The GOROOT environment variable is mostly deprecated, and no setup requires it. The go tool knows to look next to the binary path as well as at the path at which it was built (or at the build-time GOROOT_FINAL value), so it can find its GOROOT automatically.

The problem with hardcoding a GOROOT is that if any other go tool is in use (for example, because one compiled Go tip), the environment variable will override its autodetected GOROOT. The result is that the GOROOT and the go binary will mismatch, leading to obscure errors.

Related: #2452

Area for Triage:
Go

Question, Bug, or Feature?:
Bug

Virtual environments affected

• Ubuntu 16.04
• Ubuntu 18.04
• Ubuntu 20.04
• macOS 10.15
• macOS 11.0
• Windows Server 2016 R2
• Windows Server 2019

Image version
20210131.1

[maxim-lobanov]

Just a note: GOROOT variable is set up on images for a long time (~2-3 years). #2452 just adds it to the documentation.
If we would like to get rid of this variable - we should do proper communication around it to make sure that we won't break any use-cases. Also it makes sense to do these changes consistency across all images.

@FiloSottile , do you aware about any use-cases that could be broken by removing this variable?

[FiloSottile]

The only breakage I can imagine is from scripts that use $GOROOT directly for some reason, instead of $(go env GOROOT). These scripts would only work in the GitHub Actions environment, since most systems don't have $GOROOT defined.

[dsame]

The changes are moved to vm rollout and will be available soon

[miketimofeev]

The changes were deployed everywhere.
@FiloSottile thanks for bringing this up!