Go: x/tools/gopls: implement rangeFormatting LSP request

[myitcv]

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

$ go version
go version go1.12.4 linux/amd64
$ go list -m golang.org/x/tools
golang.org/x/tools v0.0.0-20190428024724-550556f78a90

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

GOARCH="amd64"

GOBIN="/home/myitcv/gostuff/src/github.com/myitcv/govim/.bin"

GOCACHE="/home/myitcv/.cache/go-build"

GOEXE=""

GOFLAGS=""

GOHOSTARCH="amd64"

GOHOSTOS="linux"

GOOS="linux"

GOPATH="/home/myitcv/gostuff"

GOPROXY=""

GORACE=""

GOROOT="/home/myitcv/gos"

GOTMPDIR=""

GOTOOLDIR="/home/myitcv/gos/pkg/tool/linux_amd64"

GCCGO="gccgo"

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-build120717318=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Considering the following govim testscript in which I attempt to range-format line numbers 3-5 (inc) in main.go:

vim ex 'e main.go'
vim ex '3,5GOVIMGoFmt'
vim ex 'noautocmd w'
cmp main.go main.go.golden

-- go.mod --
module mod

-- main.go --
package main

func main(){
fmt.Println("Hello, world")
}
-- main.go.golden --
package main

func main() {
    fmt.Println("Hello, world")
}

I get the error:

ToUTF16Column: point is missing offset

The params sent were:

&protocol.DocumentRangeFormattingParams{
    TextDocument: protocol.TextDocumentIdentifier{URI:"file://$WORK/main.go"},
    Range:        protocol.Range{
        Start: protocol.Position{Line:2, Character:0},
        End:   protocol.Position{Line:5, Character:0},
    },
    Options: protocol.FormattingOptions{},
}

What did you expect to see?

No error.

What did you see instead?

The above error.

cc @stamblerre @ianthehat

[hnlq715]

+1

[myitcv]

@hnlq715 - please add 👍 emoji responses to the original description (https://github.com/golang/go/wiki/NoPlusOne)

[ianthehat]

I think I fixed this in https://go-review.googlesource.com/c/tools/+/170186, please re-open if it is still happening.

[myitcv]

I'm still seeing this in 202502a5a924:

https://travis-ci.org/myitcv/govim/builds/515152204

[qqqasdwx]

I use vscode-go get same error , when I save a go file,I miss result
Output->go-langserver

[Error - 下午2:46:00] Request textDocument/codeAction failed.
  Message: ToUTF16Column: point is missing offset
  Code: 0 

And my settings.json

    "go.alternateTools": {
        "go-langserver": "gopls",
      },
    "go.languageServerExperimentalFeatures": {
        "format": true,
        "autoComplete": true,
        "goToDefinition": true,
        "signatureHelp": true,
        "goToTypeDefinition": true
    },
    "go.useLanguageServer": true,
    "[go]": {
        "editor.snippetSuggestions": "none",
        "editor.formatOnSave": true,
        "editor.codeActionsOnSave": {
            "source.organizeImports": true
        },
    }

I try

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

it's not ok T.T

[zippoxer]

Can reproduce on Windows 10 64 bit, Go 1.12.4, VSCode 1.33.1 and gopls@cb2dda6eabdf9160e66ca7293897f984154a7f8b (latest at this time).

VSCode settings:

  "go.useLanguageServer": true,
  "[go]": {
    "editor.snippetSuggestions": "none",
    "editor.formatOnSave": true,
    "editor.codeActionsOnSave": {
      "source.organizeImports": true
    }
  },
  "gopls": {
    "usePlaceholders": true,
    "enhancedHover": true
  },

Edit: I noticed this error is showing up every time I save a Go file.

[zippoxer]

I've found a temporary solution: convert all your source files from CRLF to LF (from Windows to Unix line endings).

Note for VSCode users: don't forget to put "files.eol": "\n" in your settings.json, otherwise new files will still use CRLF.

🍡 Yay! 🍡 Now I'm not seeing the ToUTF16Column error anymore, and gopls formats my source files when it didn't before.

Hope this helps some fellow DOSphers.

[myitcv]

@zippoxer the ToUTF16Column errors are, I think, a separate issue, and should be fixed as of https://github.com/golang/tools/commit/0c752f569a3efd362925ea641059c7c60856053f

[sleep2death]

pulled the latest 'tools', vscode with gopls is still not working...

[kylelemons]

I can confirm that my ToUTF16Column errors also went away on Windows with VSCode-Go after resetting my line endings to lf in git.

[myitcv]

I'm still seeing this despite not having any Windows line endings.

Sample stack trace (if I change a return to a panic):

panic: ToUTF16Column: point is missing offset

goroutine 5 [running]:
golang.org/x/tools/internal/span.ToUTF16Column(0x2, 0x1, 0xffffffffffffffff, 0xc00d4580d0, 0xd, 0x10, 0x1, 0x0, 0x0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/span/utf16.go:25 +0x561
golang.org/x/tools/internal/lsp/protocol.(*ColumnMapper).Position(0xc0010b0450, 0x2, 0x1, 0xffffffffffffffff, 0x0, 0x0, 0x0, 0x0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/protocol/span.go:62 +0x63
golang.org/x/tools/internal/lsp/protocol.(*ColumnMapper).Range(0xc0010b0450, 0xc0028581c0, 0x39, 0x1, 0x1, 0x0, 0x2, 0x1, 0xffffffffffffffff, 0x39, ...)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/protocol/span.go:54 +0x4b0
golang.org/x/tools/internal/lsp.ToProtocolEdits(0xc0010b0450, 0xc0005ba320, 0x2, 0x2, 0xc000182740, 0x37ec55, 0x37ec62, 0xc0005ba320, 0x2)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/format.go:68 +0x134
golang.org/x/tools/internal/lsp.organizeImports(0x8dff20, 0xc006308740, 0x8e00a0, 0xc0001c8000, 0xc0028581c0, 0x39, 0x1, 0x1, 0x0, 0x1, ...)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/code_action.go:86 +0x21e
golang.org/x/tools/internal/lsp.(*Server).codeAction(0xc0000aa7e0, 0x8dff20, 0xc006308740, 0xc003688000, 0xc003688000, 0x0, 0x0, 0x0, 0xc0005ba280)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/code_action.go:32 +0x1fb
golang.org/x/tools/internal/lsp.(*Server).CodeAction(0xc0000aa7e0, 0x8dff20, 0xc006308740, 0xc003688000, 0xc003688000, 0x0, 0x0, 0x10, 0x0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/server.go:202 +0x4d
golang.org/x/tools/internal/lsp/protocol.serverHandler.func1(0x8dff20, 0xc006308740, 0xc00014e3f0, 0xc003ebe940)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/protocol/server.go:336 +0x2bdd
golang.org/x/tools/internal/jsonrpc2.(*Conn).Run.func1(0xc000074a80, 0xc00014e3f0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/jsonrpc2/jsonrpc2.go:276 +0xda
created by golang.org/x/tools/internal/jsonrpc2.(*Conn).Run
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/jsonrpc2/jsonrpc2.go:270 +0xba

@ianthehat - is the related to the diff changes that landed not long ago?

[ianthehat]

I am confused as to what is happening here, and I can't reproduce it.
For that stack trace to be produced, the span of an edit must have an invalid end position.
It is failing in the call to m.Position(s.End()) a couple of lines after doing s, err := s.WithAll(m.Converter) which means that either that function failed to set the offset without failing, or something concurrently modified the offset

[myitcv]

Ok, I've managed to track down this particular instance of the ToUTF16Column: point is missing offset error to the case where a file contains a single line that is the package clause, with no trailing \n. Here is the sequence of events from govim's perspective:

Sequence of events

gopls server start =======================

gopls.Initialize() call; params:

&protocol.InitializeParams{

    ProcessID:    0,

    RootPath:     "",

    RootURI:      "file:///home/myitcv/gostuff/src/github.com/myitcv/playground",

    Capabilities: protocol.ClientCapabilities{

        Workspace:    struct { ApplyEdit bool "json:\"applyEdit,omitempty""; WorkspaceEdit struct { DocumentChanges bool "json:\"documentChanges,omitempty""; ResourceOperations []protocol.ResourceOperationKind "json:\"resourceOperations,omitempty""; FailureHandling protocol.FailureHandlingKind "json:\"failureHandling,omitempty"" } "json:\"workspaceEdit,omitempty""; DidChangeConfiguration struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"didChangeConfiguration,omitempty""; DidChangeWatchedFiles struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"didChangeWatchedFiles,omitempty""; Symbol struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; SymbolKind struct { ValueSet []protocol.SymbolKind "json:\"valueSet,omitempty"" } "json:\"symbolKind,omitempty"" } "json:\"symbol,omitempty""; ExecuteCommand struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"executeCommand,omitempty""; WorkspaceFolders bool "json:\"workspaceFolders,omitempty""; Configuration bool "json:\"configuration,omitempty"" }{},

        TextDocument: struct { Synchronization struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; WillSave bool "json:\"willSave,omitempty""; WillSaveWaitUntil bool "json:\"willSaveWaitUntil,omitempty""; DidSave bool "json:\"didSave,omitempty"" } "json:\"synchronization,omitempty""; Completion struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; CompletionItem struct { SnippetSupport bool "json:\"snippetSupport,omitempty""; CommitCharactersSupport bool "json:\"commitCharactersSupport,omitempty""; DocumentationFormat []protocol.MarkupKind "json:\"documentationFormat,omitempty""; DeprecatedSupport bool "json:\"deprecatedSupport,omitempty""; PreselectSupport bool "json:\"preselectSupport,omitempty"" } "json:\"completionItem,omitempty""; CompletionItemKind struct { ValueSet []protocol.CompletionItemKind "json:\"valueSet,omitempty"" } "json:\"completionItemKind,omitempty""; ContextSupport bool "json:\"contextSupport,omitempty"" } "json:\"completion,omitempty""; Hover struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; ContentFormat []protocol.MarkupKind "json:\"contentFormat,omitempty"" } "json:\"hover,omitempty""; SignatureHelp struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; SignatureInformation struct { DocumentationFormat []protocol.MarkupKind "json:\"documentationFormat,omitempty""; ParameterInformation struct { LabelOffsetSupport bool "json:\"labelOffsetSupport,omitempty"" } "json:\"parameterInformation,omitempty"" } "json:\"signatureInformation,omitempty"" } "json:\"signatureHelp,omitempty""; References struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"references,omitempty""; DocumentHighlight struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"documentHighlight,omitempty""; DocumentSymbol struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; SymbolKind struct { ValueSet []protocol.SymbolKind "json:\"valueSet,omitempty"" } "json:\"symbolKind,omitempty""; HierarchicalDocumentSymbolSupport bool "json:\"hierarchicalDocumentSymbolSupport,omitempty"" } "json:\"documentSymbol,omitempty""; Formatting struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"formatting,omitempty""; RangeFormatting struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"rangeFormatting,omitempty""; OnTypeFormatting struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"onTypeFormatting,omitempty""; Definition struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; LinkSupport bool "json:\"linkSupport,omitempty"" } "json:\"definition,omitempty""; CodeAction struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; CodeActionLiteralSupport struct { CodeActionKind struct { ValueSet []protocol.CodeActionKind "json:\"valueSet"" } "json:\"codeActionKind"" } "json:\"codeActionLiteralSupport,omitempty"" } "json:\"codeAction,omitempty""; CodeLens struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"codeLens,omitempty""; DocumentLink struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"documentLink,omitempty""; Rename struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; PrepareSupport bool "json:\"prepareSupport,omitempty"" } "json:\"rename,omitempty""; PublishDiagnostics struct { RelatedInformation bool "json:\"relatedInformation,omitempty""; TagSupport bool "json:\"tagSupport,omitempty"" } "json:\"publishDiagnostics,omitempty""; Implementation struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; LinkSupport bool "json:\"linkSupport,omitempty"" } "json:\"implementation,omitempty""; TypeDefinition struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; LinkSupport bool "json:\"linkSupport,omitempty"" } "json:\"typeDefinition,omitempty""; ColorProvider struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"colorProvider,omitempty""; FoldingRange struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; RangeLimit float64 "json:\"rangeLimit,omitempty""; LineFoldingOnly bool "json:\"lineFoldingOnly,omitempty"" } "json:\"foldingRange,omitempty""; Declaration struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; LinkSupport bool "json:\"linkSupport,omitempty"" } "json:\"declaration,omitempty""; SelectionRange struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" } "json:\"selectionRange,omitempty"" }{

            Synchronization: struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; WillSave bool "json:\"willSave,omitempty""; WillSaveWaitUntil bool "json:\"willSaveWaitUntil,omitempty""; DidSave bool "json:\"didSave,omitempty"" }{},

            Completion:      struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; CompletionItem struct { SnippetSupport bool "json:\"snippetSupport,omitempty""; CommitCharactersSupport bool "json:\"commitCharactersSupport,omitempty""; DocumentationFormat []protocol.MarkupKind "json:\"documentationFormat,omitempty""; DeprecatedSupport bool "json:\"deprecatedSupport,omitempty""; PreselectSupport bool "json:\"preselectSupport,omitempty"" } "json:\"completionItem,omitempty""; CompletionItemKind struct { ValueSet []protocol.CompletionItemKind "json:\"valueSet,omitempty"" } "json:\"completionItemKind,omitempty""; ContextSupport bool "json:\"contextSupport,omitempty"" }{},

            Hover:           struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; ContentFormat []protocol.MarkupKind "json:\"contentFormat,omitempty"" }{

                DynamicRegistration: false,

                ContentFormat:       {"plaintext"},

            },

            SignatureHelp:      struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; SignatureInformation struct { DocumentationFormat []protocol.MarkupKind "json:\"documentationFormat,omitempty""; ParameterInformation struct { LabelOffsetSupport bool "json:\"labelOffsetSupport,omitempty"" } "json:\"parameterInformation,omitempty"" } "json:\"signatureInformation,omitempty"" }{},

            References:         struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

            DocumentHighlight:  struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

            DocumentSymbol:     struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; SymbolKind struct { ValueSet []protocol.SymbolKind "json:\"valueSet,omitempty"" } "json:\"symbolKind,omitempty""; HierarchicalDocumentSymbolSupport bool "json:\"hierarchicalDocumentSymbolSupport,omitempty"" }{},

            Formatting:         struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

            RangeFormatting:    struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

            OnTypeFormatting:   struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

            Definition:         struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; LinkSupport bool "json:\"linkSupport,omitempty"" }{},

            CodeAction:         struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; CodeActionLiteralSupport struct { CodeActionKind struct { ValueSet []protocol.CodeActionKind "json:\"valueSet"" } "json:\"codeActionKind"" } "json:\"codeActionLiteralSupport,omitempty"" }{},

            CodeLens:           struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

            DocumentLink:       struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

            Rename:             struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; PrepareSupport bool "json:\"prepareSupport,omitempty"" }{},

            PublishDiagnostics: struct { RelatedInformation bool "json:\"relatedInformation,omitempty""; TagSupport bool "json:\"tagSupport,omitempty"" }{},

            Implementation:     struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; LinkSupport bool "json:\"linkSupport,omitempty"" }{},

            TypeDefinition:     struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; LinkSupport bool "json:\"linkSupport,omitempty"" }{},

            ColorProvider:      struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

            FoldingRange:       struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; RangeLimit float64 "json:\"rangeLimit,omitempty""; LineFoldingOnly bool "json:\"lineFoldingOnly,omitempty"" }{},

            Declaration:        struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty""; LinkSupport bool "json:\"linkSupport,omitempty"" }{},

            SelectionRange:     struct { DynamicRegistration bool "json:\"dynamicRegistration,omitempty"" }{},

        },

        Experimental: nil,

    },

    InitializationOptions: nil,

    Trace:                 "",

    WorkspaceFolders:      nil,

}

gopls server end =======================

gopls server start =======================

gopls.Initialize() return; err: ; res:

&protocol.InitializeResult{

    Capabilities: protocol.ServerCapabilities{

        TextDocumentSync: map[string]interface {}{

            "openClose": bool(true),

            "change":    float64(1),

        },

        HoverProvider:      true,

        CompletionProvider: &protocol.CompletionOptions{

            TriggerCharacters:   {"."},

            AllCommitCharacters: nil,

            ResolveProvider:     false,

        },

        SignatureHelpProvider: &protocol.SignatureHelpOptions{

            TriggerCharacters: {"(", ","},

        },

        DefinitionProvider:               true,

        ReferencesProvider:               false,

        DocumentHighlightProvider:        true,

        DocumentSymbolProvider:           true,

        WorkspaceSymbolProvider:          false,

        CodeActionProvider:               true,

        CodeLensProvider:                 (protocol.CodeLensOptions)(nil),

        DocumentFormattingProvider:       true,

        DocumentRangeFormattingProvider:  true,

        DocumentOnTypeFormattingProvider: (struct { FirstTriggerCharacter string "json:\"firstTriggerCharacter""; MoreTriggerCharacter []string "json:\"moreTriggerCharacter,omitempty"" })(nil),

        RenameProvider:                   (protocol.RenameOptions)(nil),

        DocumentLinkProvider:             (protocol.DocumentLinkOptions)(nil),

        ExecuteCommandProvider:           (protocol.ExecuteCommandOptions)(nil),

        Experimental:                     nil,

        ImplementationProvider:           false,

        TypeDefinitionProvider:           true,

        Workspace:                        (struct { WorkspaceFolders struct { Supported bool "json:\"supported,omitempty""; ChangeNotifications string "json:\"changeNotifications,omitempty"" } "json:\"workspaceFolders,omitempty"" })(nil),

        ColorProvider:                    false,

        FoldingRangeProvider:             false,

        DeclarationProvider:              false,

        SelectionRangeProvider:           false,

    },

    Custom: {},

}

gopls server end =======================

gopls server start =======================

gopls.DidOpen() call; params:

&protocol.DidOpenTextDocumentParams{

    TextDocument: protocol.TextDocumentItem{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/main.go", LanguageID:"", Version:0, Text:"package main\n"},

}

gopls server end =======================

gopls server start =======================

gopls.DidOpen() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidOpen() call; params:

&protocol.DidOpenTextDocumentParams{

    TextDocument: protocol.TextDocumentItem{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go", LanguageID:"", Version:0, Text:""},

}

gopls server end =======================

gopls server start =======================

gopls.DidOpen() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                1,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "p",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                2,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "pa",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                3,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "pac",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                4,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "pack",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                5,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "packa",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                6,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "packag",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                7,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "package",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                8,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "package ",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                9,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "package m",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                10,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "package ma",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                11,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (protocol.Range)(nil),

            RangeLength: 0,

            Text:        "package mai",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.DidChange() call; params:

&protocol.DidChangeTextDocumentParams{

    TextDocument: protocol.VersionedTextDocumentIdentifier{

        Version:                12,

        TextDocumentIdentifier: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    },

    ContentChanges: {

        {

            Range:       (*protocol.Range)(nil),

            RangeLength: 0,

            Text:        "package main",

        },

    },

}

gopls server end =======================

gopls server start =======================

gopls.DidChange() return; err: 

gopls server end =======================

gopls server start =======================

gopls.CodeAction() call; params:

&protocol.CodeActionParams{

    TextDocument: protocol.TextDocumentIdentifier{URI:"file:///home/myitcv/gostuff/src/github.com/myitcv/playground/blah.go"},

    Range:        protocol.Range{},

    Context:      protocol.CodeActionContext{},

}

gopls server end =======================

which gives rise to the following exception:

panic: ToUTF16Column: point is missing offset

goroutine 5 [running]:
golang.org/x/tools/internal/span.ToUTF16Column(0x2, 0x1, 0xffffffffffffffff, 0xc0003c02f0, 0xc, 0x10, 0x1, 0x0, 0x0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/span/utf16.go:25 +0x561
golang.org/x/tools/internal/lsp/protocol.(*ColumnMapper).Position(0xc0003fe150, 0x2, 0x1, 0xffffffffffffffff, 0x0, 0x0, 0x0, 0x0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/protocol/span.go:62 +0x63
golang.org/x/tools/internal/lsp/protocol.(*ColumnMapper).Range(0xc0003fe150, 0xc000188460, 0x44, 0x1, 0x1, 0x0, 0x2, 0x1, 0xffffffffffffffff, 0x44, ...)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/protocol/span.go:54 +0x4b0
golang.org/x/tools/internal/lsp.ToProtocolEdits(0xc0003fe150, 0xc0003f80a0, 0x2, 0x2, 0xc000182740, 0x16b, 0x177, 0xc0003f80a0, 0x2)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/format.go:68 +0x134
golang.org/x/tools/internal/lsp.organizeImports(0x8dff20, 0xc000222b80, 0x8e00a0, 0xc0001c4000, 0xc000188460, 0x44, 0x1, 0x1, 0x0, 0x1, ...)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/code_action.go:86 +0x21e
golang.org/x/tools/internal/lsp.(*Server).codeAction(0xc0000a87e0, 0x8dff20, 0xc000222b80, 0xc0003f6000, 0xc0003f6000, 0x0, 0x0, 0x0, 0xc0003f8000)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/code_action.go:32 +0x1fb
golang.org/x/tools/internal/lsp.(*Server).CodeAction(0xc0000a87e0, 0x8dff20, 0xc000222b80, 0xc0003f6000, 0xc0003f6000, 0x0, 0x0, 0x0, 0x0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/server.go:202 +0x4d
golang.org/x/tools/internal/lsp/protocol.serverHandler.func1(0x8dff20, 0xc000222b80, 0xc00014c3f0, 0xc000228ec0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/lsp/protocol/server.go:336 +0x2bdd
golang.org/x/tools/internal/jsonrpc2.(*Conn).Run.func1(0xc000072a80, 0xc00014c3f0)
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/jsonrpc2/jsonrpc2.go:276 +0xda
created by golang.org/x/tools/internal/jsonrpc2.(*Conn).Run
    /tmp/tmp.xetMpJpdla/golang.org/x/tools/internal/jsonrpc2/jsonrpc2.go:270 +0xba

If instead of simply writing package main to blah.go I write package main\n (i.e. there is a trailing newline), then I don't see any issues.

[iwittkau]

I had the same issue on a fresh macOS install today (latests Go, VSCode and tools). I was able to resolve the issue by using gofmt -w file.go on the offending file.go. The file contained copied code from json-to-go.

[gopherbot]

Change https://golang.org/cl/175938 mentions this issue: internal/lsp: disable rangeFormatting temporarily

[stamblerre]

It seems that range formatting has actually not been working for quite some time - temporarily disabling it until we find a good solution. Formatting should still work correctly however.