x/tools/cmd/gopls: "build cache is required, but could not be located: GOCACHE is not defined and $HOME is not defined"

[23doors]

What did you do?

Open go file in VSCode configured for using gopls language server.

What did you expect to see?

No errors and working gopls.

What did you see instead?

Error on my package statement:

[Error - 11:39:40 PM] unable to check package for file:///<removed>.go: go [list -f {{context.GOARCH}} {{context.Compiler}} -- unsafe]: exit status 1: build cache is required, but could not be located: GOCACHE is not defined and $HOME is not defined

Build info

Installed gopls through:

go get -u golang.org/x/tools/cmd/gopls

This used to work a few days ago so I tested different commits and it seems that:
2c78df6 is the most recent one that works (no errors). And next one: golang/tools@7927dba causes it to break.

Go info

go version go1.12.5 darwin/amd64

[zchee]

@23doors
Maybe it's workaround, but just set "gopls.env": {"GOPATH": "your gopath", "GOCACHE": "your gocache"} to your settings.json (settings.json is correct name? I forgot. I don't usually use vscode, I'm Neovim user)

Also, Now typing iPhone. might be invalid json syntax, sorry.

[23doors]

@zchee this fixed it, thank you! But on 2c78df6 I wasn't required to set it, so this seems like a regression or a vscode-go issue. Also, I used same GOPATH and GOCACHE as from go env output.

[zchee]

@23doors
yes, maybe caused by any regression or vscode-go issue.

Also, I used same GOPATH and GOCACHE as from go env output.

It means set settings.json to same values from go env, right?
If so, your seeting is correct. seems to now didn't parses GOPATH and GOCACHE or some values caused by any bugs.

Unfortunately, I don't know which is buggy, because I first read gopls source code and first lauch vscode yesterday lol
I found this workaround when debugging this issue:
#29202 (comment)

[bcmills]

CC @stamblerre @ianthehat

[stamblerre]

Can you provide a gopls log with redacted filenames? It can be found by going to "View: Debug Console" -> "Output" -> "Tasks" -> "gopls". At the very least, the top of your log would be helpful because it prints out your environment information. The error message you provided is surprising because we never run any go list command that looks like that.

[23doors]

@stamblerre here it is, redacted file names and removed duplicate messages:

[Info  - 10:03:05 PM] #### Build info

no module information, gopls not built in module mode


#### Go info

go version go1.12.5 darwin/amd64

GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/V/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/V/Go"
GOPROXY="https://proxy.golang.org"
GORACE=""
GOROOT="/usr/local/Cellar/go/1.12.5/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.12.5/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2 -w"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/pd/hq5jjzqd6wq07z6xcrc1875m0000gr/T/go-build712859041=/tmp/go-build -gno-record-gcc-switches -fno-common"

[Error - 10:03:05 PM] unable to check package for file:///Users/V/Projects/redacted.go: go [list -f {{context.GOARCH}} {{context.Compiler}} -- unsafe]: exit status 1: build cache is required, but could not be located: GOCACHE is not defined and $HOME is not defined

[Error - 10:03:06 PM] failed to deliver diagnostic for file:///Users/V/Projects/redacted/go%20%5Blist%20-f%20%7B%7Bcontext.GOARCH%7D%7D%20%7B%7Bcontext.Compiler%7D%7D%20--%20unsafe%5D: unsupported file extension: .Compiler}} -- unsafe]
[Error - 10:03:06 PM] unable to check package for file:///Users/V/Projects/redacted.go: go [list -f {{context.GOARCH}} {{context.Compiler}} -- unsafe]: exit status 1: build cache is required, but could not be located: GOCACHE is not defined and $HOME is not defined

[Error - 10:03:06 PM] Request textDocument/codeAction failed.
  Message: no file information for file:///Users/V/Projects/redacted.go
  Code: 0 
[Error - 10:03:06 PM] unable to check package for file:///Users/V/Projects/redacted.go: go [list -f {{context.GOARCH}} {{context.Compiler}} -- unsafe]: exit status 1: build cache is required, but could not be located: GOCACHE is not defined and $HOME is not defined

[Error - 10:03:06 PM] Request textDocument/documentLink failed.
  Message: no AST for file:///Users/V/Projects/redacted.go
  Code: 0 
[Error - 10:03:06 PM] unable to check package for file:///Users/V/Projects/redacted.go: go [list -f {{context.GOARCH}} {{context.Compiler}} -- unsafe]: exit status 1: build cache is required, but could not be located: GOCACHE is not defined and $HOME is not defined

[Error - 10:03:06 PM] Request textDocument/hover failed.
  Message: no AST for file:///Users/V/Projects/redacted.go
  Code: 0 

[stamblerre]

Thank you for sharing! I was actually just able to reproduce this error, so I will be investigating it ASAP.

[stamblerre]

This should be fixed with https://golang.org/cl/179221.