x/tools/gopls: improve presentation of package loading failure caused by cgo errors

[hyangah]

gopls: v0.6.1

I encountered a repo that uses cgo and requires tools (e.g.pkg-config, ...) and correct configuration to build cgo.
Loading packages took a while and eventually failed because of my incomplete configuration. The PROBLEMS (diagnostics) section is flooded with hundreds of errors related to cgo types

I could find the reasons from the gopls (server) trace channel of vscode. But it would be better to expose these error in the diagnostics page or with other means. Also, consider suppressing all the cgo-related type errors when the root cause is obvious. Finding the root cause out of hundreds of type errors seems impossible.

[Error - 3:28:30 PM] 2020/12/21 15:28:30 initial workspace load failed: go [-e -json -compiled=true -test=true -export=false -deps=true -find=false -- builtin github.com/some/repo/...]: exit status 2: go: downloading golang.org/x/net v0.0.0-20201031054903-ff519b6c9102
go: downloading github.com/stretchr/testify v1.6.1
...
go: downloading golang.org/x/text v0.3.4
# pkg-config --cflags  -- vips vips vips vips vips vips vips vips vips vips vips vips vips vips
pkg-config: exec: "pkg-config": executable file not found in $PATH
# pkg-config --cflags  -- vips vips vips vips vips vips vips vips vips vips vips vips vips vips
pkg-config: exec: "pkg-config": executable file not found in $PATH

[stamblerre]

Was the go list error shown at the bottom of the screen? If not, that definitely seems like a problem.

[hyangah]

No. I don't see any go list error message outside the gopls server trace.

Also, tried regenerate cgo definitions codelens. There was no visible change or error message, which needs improvement.

[Trace - 16:54:37.207 PM] Sending request 'workspace/executeCommand - (19)'.
Params: {"command":"gopls.regenerate_cgo","arguments":["file:///work/govips/vips/arithmetic.go"]}


[Trace - 16:54:37.209 PM] Received request 'window/workDoneProgress/create - (6)'.
Params: {"token":"6129484611666145821"}


[Trace - 16:54:37.211 PM] Sending response 'window/workDoneProgress/create - (6)' in 1ms.
Result: 


[Trace - 16:54:37.211 PM] Received notification '$/progress'.
Params: {"token":"6129484611666145821","value":{"kind":"begin","title":"Regenerate cgo","cancellable":true,"message":"Running..."}}


[Trace - 16:54:37.218 PM] Received notification '$/progress'.
Params: {"token":"6129484611666145821","value":{"kind":"end","message":"gopls.regenerate_cgo: completed"}}


[Trace - 16:54:37.218 PM] Received response 'workspace/executeCommand - (19)' in 10ms.
Result: null

I happened to try github.com/davidbyttow/govips but we can create a minimal repro for testing.

[stamblerre]

I have a CL to make the error message pop-up, but this also looks like a regression in #36770. Reopened that issue.

[gopherbot]

Change https://golang.org/cl/280093 mentions this issue: internal/lsp: restructure the way we report critical errors