x/tools/gopls: formatting resets cursor after save with CRLF line endings

[deanveloper]

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

$ go version
go version go1.12.5 windows/amd64

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
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\[redacted]\AppData\Local\go-build
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=C:\Users\[redacted]\go
set GOPROXY=
set GORACE=
set GOROOT=C:\Go
set GOTMPDIR=
set GOTOOLDIR=C:\Go\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=C:\Users\[redacted]\AppData\Local\Temp\go-build065388570=/tmp/go-build -gno-record-gcc-switches

What did you do?

Saved a .go file

What did you expect to see?

My cursor should stay in the same place after formatting

What did you see instead?

My cursor is reset to the beginning of the file. I have tried toggling the [go] > editor.codeActionsOnSave and go.lintOnSave settings to false and it still occurs.

VSCode Settings

Go extension: 0.10.2

{
    "git.autofetch": true,
    "files.associations": {
        "*.tmpl": "gotemplate"
    },
    "terminal.integrated.shell.windows": "C:\\Program Files\\Git\\bin\\bash.exe",
    "go.useLanguageServer": true,
    "go.languageServerExperimentalFeatures": {
            "diagnostics": true // for diagnostics as you type
    },
    "[go]": {
        "editor.snippetSuggestions": "none",
        "editor.codeActionsOnSave": {
            "source.organizeImports": true
        },
    },
    "gopls": {
        "usePlaceholders": true, // add parameter placeholders when completing a function
        "enhancedHover": true,   // experimental to improve quality of hover (will be on by default soon)
    },
    "go.lintOnSave": "off"
}

[stamblerre]

Does this happen often or just a single time? Do you have a case that could reproduce it?

[deanveloper]

It happens every time, a condition I have found is that it must be in a Go module. I have not tested with gopath yet, but when editing Go files that are not in Go modules, the editor does nothing on save and the cursor isn't affected.

I haven't gotten around to testing it more yet. It appeared that it formatted the code even when I had turned "format on save" off. It happens on my work computer, I haven't tested on my home computer yet but I'll get back when I do.

[stamblerre]

My initial guess is that it has something to do with your configurations with gopls and other formatting tools. gopls intentionally returns diffs rather than a full file replacement to avoid this issue, so I wonder if you are also somehow running gofmt or goimports instead of gopls.

You could try explicitly turning off formatting and import organization through gopls to see if it still happens:

"go.languageServerExperimentalFeatures": {
            "format": false
},
"[go]": {
        "editor.codeActionsOnSave": {
            "source.organizeImports": true
        },
},

[deanveloper]

It looks like if either go.languageServerExperimentalFeatures > format or [go] > editor.codeActionsOnSave > source.organizeImports are enabled that my cursor is reset. I'll check this on my home machine tonight, however I haven't had any issues from there from what I've tested on it.

When both are set to false, the file still gets formatted, but the cursor is not reset.

My configuration where it is "working"

{
    "git.autofetch": true,
    "files.associations": {
        "*.tmpl": "gotemplate",
        "*.html.tmpl": "gohtml",
    },
    "terminal.integrated.shell.windows": "C:\\Program Files\\Git\\bin\\bash.exe",
    "go.useLanguageServer": true,
    "go.languageServerExperimentalFeatures": {
        "format": false,
        "diagnostics": true // for diagnostics as you type
    },
    "[go]": {
        "editor.codeActionsOnSave": {
            "source.organizeImports": false
        },
    },
    "gopls": {
        "usePlaceholders": true, // add parameter placeholders when completing a function
        "enhancedHover": true, // experimental to improve quality of hover (will be on by default soon)
    },
    "go.lintOnSave": "off",
    "editor.formatOnSave": true
}

Edit: editor.formatOnSave does not seem to affect anything

[stamblerre]

I should have asked earlier - when was the last time you updated gopls? My best guess is that you are using an old version. Can you update to the latest and confirm if the issue still happens (go get -u golang.org/x/tools/cmd/gopls)?

[deanveloper]

I ran the command and it looks like nothing has changed

[stamblerre]

Thanks for letting me know. My next guess is that perhaps it has something to do with the fact that you are on Windows? Can you try switching to Unix line endings by adding "files.eol": "\n" to your VSCode settings?

[deanveloper]

Well that changed something - the cursor now resets to the beginning of the line rather than the beginning of the file.

[stamblerre]

Hm, that is so strange. I've never heard of anyone experiencing this kind of behavior on Windows. I will try to reproduce this and see if I can come up with a fix.