x/tools/gopls: quickfix_empty_files (govim) test flaky

[myitcv]

What version of Go are you using (go version)?

$ go version
go version devel +73d213708e Sat Jan 25 16:34:18 2020 +0000 linux/amd64
$ go list -m golang.org/x/tools
golang.org/x/tools v0.0.0-20200124220429-8fe064f891f2
$ go list -m golang.org/x/tools/gopls
golang.org/x/tools/gopls v0.1.8-0.20200124220429-8fe064f891f2

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/myitcv/.cache/go-build"
GOENV="/home/myitcv/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/myitcv/gostuff"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/myitcv/gos"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/myitcv/gos/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/myitcv/gostuff/src/github.com/myitcv/govim/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build059125969=/tmp/go-build -gno-record-gcc-switches"

What did you do?

This is somewhat similar to #36661

We have just added a new govim test that seeks to verify diagnostics are as expected where initially empty .go files exist on disk, but changes to populate those files are then made (but not saved) within the editor.

Like #36661, the scenario involves creating a package p with a simple function DoIt. p is imported by a main package. p also has a test file that exercises DoIt, and an external test file that does the same.

Initially all call sites for DoIt incorrectly pass an integer argument, meaning we should have error diagnostics for all call sites. Then we correct the definition of DoIt to take an integer argument at which point all diagnostics should disappear.

The test can be seen here:

https://github.com/govim/govim/blob/cmd_govim_add_tests_where_files_initially_empty/cmd/govim/testdata/scenario_default/quickfix_empty_files.txt

What did you expect to see?

The diagnostic error:

cannot convert 5 (untyped int constant) to string

for each of the files main.go, p/x_test.go and p/p_test.go

What did you see instead?

Random results

• Sometimes we are missing any diagnostics for main.go
• Sometimes we get package p; expected p_test for p/p.go
• Sometimes we get "could not import mod.com/p (no parsed files for package mod.com/p, expected: [], errors: [], list errors: [-: p/p.go:1:1: expected 'package', found 'EOF']) for p/x_test.go

One such gopls log file:
gopls.log

Tentatively marking as v0.3.0

---

cc @stamblerre

FYI @leitzler

[myitcv]

Note the test linked above is not yet merged, but can be run locally via:

cd $(mktemp -d)
git clone https://github.com/govim/govim
cd govim
git fetch origin pull/727/head && git checkout FETCH_HEAD
sed -i '/skip/d' cmd/govim/testdata/scenario_default/quickfix_empty_files.txt
go test -exec="dockexec govim/govim:latest-vim -t -e VIM_FLAVOR=vim" -count=1 -v -run "TestScripts/scenario_default/quickfix_empty_files" ./cmd/govim

If you want to use gopls from your PATH, change that last line to:

go test -exec="dockexec govim/govim:latest-vim -t -e VIM_FLAVOR=vim -v $(which gopls):/usr/local/bin/gopls -e GOVIM_USE_GOPLS_FROM_PATH=true" -count=1 -v -run "TestScripts/scenario_default/quickfix_empty_files" ./cmd/govim

[stamblerre]

I believe that https://golang.org/cl/216310 will have fixed this issue.

[gopherbot]

Change https://golang.org/cl/216637 mentions this issue: internal/lsp: recover from a view initialization failure

[stamblerre]

I spoke too soon, but I was able to reproduce and debug this test. The CL above fixed it for me.

[myitcv]

We're also seeing issues here that look remarkably similar to #36661 (comment). I'll gather log files.

[myitcv]

Here are log files with verbose output turned on:

• Fail: fail.log
• Pass: pass.log