x/tools/gopls: diagnostics version is reused for same diagnostic

[leitzler]

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

$ go version
go version go1.13.5 darwin/amd64
$ go list -m golang.org/x/tools
golang.org/x/tools v0.0.0-20200108203644-89082a384178
$ go list -m golang.org/x/tools/gopls
golang.org/x/tools/gopls v0.1.8-0.20200108203644-89082a384178

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/pontus/Library/Caches/go-build"
GOENV="/Users/pontus/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/pontus/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/pontus/proj/govim/latest/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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/go-build710948783=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Open a main.go with the following content (no errors/warnings):

package main

func main() {

}

gopls sends diagnostics Version 1 with no diagnostics:

[Trace - 10:26:41.794 AM] Received notification 'window/logMessage'.
Params: {"type":1,"message":"2020/01/09 10:26:41 no diagnostics: context canceled\n\tURI = file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go"}

[Trace - 10:26:41.798 AM] Received notification 'textDocument/publishDiagnostics'.
Params: {"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go","version":1,"diagnostics":[]}

Then I add a a inside func main():

package main

func main() {
a
}

That triggers a didChange to gopls, and gopls responds with Version 2 of the diagnostics:

[Trace - 10:27:08.079 AM] Sending notification 'textDocument/didChange'.
Params: {"textDocument":{"version":2,"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go"},"contentChanges":[{"range":{"start":{"line":3,"character":0},"end":{"line":4,"character":0}},"text":"a\n"}]}

[Trace - 10:27:08.085 AM] Received notification 'textDocument/publishDiagnostics'.
Params: {"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go","version":2,"diagnostics":[{"range":{"start":{"line":3,"character":0},"end":{"line":3,"character":1}},"severity":1,"source":"compiler","message":"undeclared name: a"}]}

I remove the a again, triggering another didChange (Version 3) to gopls and at this point I get Version 1 back again:

[Trace - 10:27:28.647 AM] Sending notification 'textDocument/didChange'.
Params: {"textDocument":{"version":3,"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go"},"contentChanges":[{"range":{"start":{"line":3,"character":0},"end":{"line":4,"character":0}},"text":"\n"}]}

[Trace - 10:27:28.653 AM] Received notification 'textDocument/publishDiagnostics'.
Params: {"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go","version":1,"diagnostics":[]}

I re-add a at the same position again, and get Version 2 of the diagnostics:

[Trace - 10:27:34.830 AM] Sending notification 'textDocument/didChange'.
Params: {"textDocument":{"version":4,"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go"},"contentChanges":[{"range":{"start":{"line":3,"character":0},"end":{"line":4,"character":0}},"text":"a\n"}]}

[Trace - 10:27:34.835 AM] Received notification 'textDocument/publishDiagnostics'.
Params: {"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go","version":2,"diagnostics":[{"range":{"start":{"line":3,"character":0},"end":{"line":3,"character":1}},"severity":1,"source":"compiler","message":"undeclared name: a"}]}

Repeat:

[Trace - 10:27:45.058 AM] Sending notification 'textDocument/didChange'.
Params: {"textDocument":{"version":5,"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go"},"contentChanges":[{"range":{"start":{"line":3,"character":0},"end":{"line":4,"character":0}},"text":"\n"}]}

[Trace - 10:27:45.066 AM] Received notification 'textDocument/publishDiagnostics'.
Params: {"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go","version":1,"diagnostics":[]}

[Trace - 10:27:52.450 AM] Sending notification 'textDocument/didChange'.
Params: {"textDocument":{"version":6,"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go"},"contentChanges":[{"range":{"start":{"line":3,"character":0},"end":{"line":4,"character":0}},"text":"a\n"}]}

[Trace - 10:27:52.452 AM] Received notification 'textDocument/publishDiagnostics'.
Params: {"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go","version":2,"diagnostics":[{"range":{"start":{"line":3,"character":0},"end":{"line":3,"character":1}},"severity":1,"source":"compiler","message":"undeclared name: a"}]}

[Trace - 10:28:03.645 AM] Sending notification 'textDocument/didChange'.
Params: {"textDocument":{"version":7,"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go"},"contentChanges":[{"range":{"start":{"line":3,"character":0},"end":{"line":4,"character":0}},"text":"\n"}]}

[Trace - 10:28:03.652 AM] Received notification 'textDocument/publishDiagnostics'.
Params: {"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go","version":1,"diagnostics":[]}

If I then add b instead, gopls responds with the correct version:

[Trace - 10:28:12.194 AM] Sending notification 'textDocument/didChange'.
Params: {"textDocument":{"version":8,"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go"},"contentChanges":[{"range":{"start":{"line":3,"character":0},"end":{"line":4,"character":0}},"text":"b\n"}]}

[Trace - 10:28:12.197 AM] Received notification 'textDocument/publishDiagnostics'.
Params: {"uri":"file:///private/var/folders/xm/ls208xd174v95pgd20rn_qbh0000gn/T/tmp.kvOApBCf/main.go","version":8,"diagnostics":[{"range":{"start":{"line":3,"character":0},"end":{"line":3,"character":1}},"severity":1,"source":"compiler","message":"undeclared name: b"}]}

What did you expect to see?

A new version each time that corresponds to the didChange.

[myitcv]

As @leitzler has just linked, when we fixed gopls to ignore non-new diagnostics (per #36452 (comment)) we immediately ran into this issue.

[stamblerre]

Thanks for reporting this issue! I think this issue must have existed for a while. It's definitely a caching issue, and we haven't noticed it in VS Code because VS Code will actually go back to old file versions if they are the same. For example, if a file's version 1 contains "foo", and then version 2 contains "fo", and then the next version goes back to "foo", VS Code will send version 1 for that second didChange. govim isn't doing that, which is why this error gets picked up. I'll take a look.

[leitzler]

Just a note, after https://golang.org/cl/213820/ was merged (tested with golang.org/x/tools/gopls v0.1.8-0.20200110042803-e2f26524b78c) old diagnostics aren't sent any longer.

That has impact on this issue as it is now a bit more severe when gopls never sends diagnostics that it has sent before. Most notable is that gopls won't clear diagnostics (send empty diagnostics) after doing it the first time.

[myitcv]

I'm fairly certain we're still seeing this problem as of a7a6caa

Starting with:

package main

func main() {
}

I then edit to take the file to:

package main

func main() {
        a
}

Then delete the a to take the file back to:

package main

func main() {
        
}

In my manual testing just now, this either leaves gopls in a state where it thinks:

1. there are no errors in the file (despite the a being an error)
2. there is always an error in the file (despite there being no a)

A gopls log file where I saw case 1 is attached:
fail.log

Note the last publishing of diagnostics is:

Params: {"uri":"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/main.go","version":4,"diagnostics":[]}

Despite the fact that after that there are versions of the file, namely 5, 7 and 9, where there is again an error in the file (albeit the same error that was first introduced in version 3)

[gopherbot]

Change https://golang.org/cl/214418 mentions this issue: internal/lsp: associate error messages with URIs, not file identities

[gopherbot]

Change https://golang.org/cl/214422 mentions this issue: internal/lsp: use latest file versions in diagnostics

[leitzler]

Tested with golang.org/x/tools/gopls v0.1.8-0.20200114052453-d31a08c2edf2 and the original issue remains, reopen?
My bad, works like a charm.

[myitcv]

Just to confirm, per @leitzler's edit to that previous message, everything appears to be working as far as this test is concerned. Thanks for the fix!