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https://github.com/golang/go
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de023d59a5
With #34111, we are forwarding the LSP from one gopls instance to another. This exposed an asymmetry in our LSP dispatching: for both ClientDispatcher and ServerDispatcher, we unmarshal to non-nil response structs. This means that when forwarding the LSP, we translate empty JSON responses (corresponding to nil values) into the non-nil zero value. This causes problems for some editors, as reported in #37570. Fix it by instead unmarshaling to a pointer. This is, of course, a somewhat dangerous change. I fixed the one NPE that occurred in tests, and have done some mild manual testing. I wouldn't be surprised if we discover more NPEs later on, but I still think this is the right change to make. Updates golang/go#34111 Fixes golang/go#37570 Change-Id: Ie69e92d2821c829cdfc4f4ab303679a725f1f859 Reviewed-on: https://go-review.googlesource.com/c/tools/+/222058 Reviewed-by: Peter Weinberger <pjw@google.com> Reviewed-by: Rebecca Stambler <rstambler@golang.org> Run-TryBot: Robert Findley <rfindley@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
89 lines
2.0 KiB
Go
89 lines
2.0 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package cmd
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import (
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"context"
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"flag"
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"fmt"
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"golang.org/x/tools/internal/lsp/protocol"
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"golang.org/x/tools/internal/span"
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"golang.org/x/tools/internal/tool"
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)
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// signature implements the signature verb for gopls
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type signature struct {
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app *Application
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}
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func (r *signature) Name() string { return "signature" }
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func (r *signature) Usage() string { return "<position>" }
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func (r *signature) ShortHelp() string { return "display selected identifier's signature" }
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func (r *signature) DetailedHelp(f *flag.FlagSet) {
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fmt.Fprint(f.Output(), `
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Example:
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$ # 1-indexed location (:line:column or :#offset) of the target identifier
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$ gopls signature helper/helper.go:8:6
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$ gopls signature helper/helper.go:#53
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gopls signature flags are:
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`)
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f.PrintDefaults()
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}
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func (r *signature) Run(ctx context.Context, args ...string) error {
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if len(args) != 1 {
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return tool.CommandLineErrorf("signature expects 1 argument (position)")
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}
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conn, err := r.app.connect(ctx)
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if err != nil {
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return err
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}
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defer conn.terminate(ctx)
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from := span.Parse(args[0])
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file := conn.AddFile(ctx, from.URI())
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if file.err != nil {
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return file.err
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}
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loc, err := file.mapper.Location(from)
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if err != nil {
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return err
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}
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tdpp := protocol.TextDocumentPositionParams{
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TextDocument: protocol.TextDocumentIdentifier{
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URI: protocol.URIFromSpanURI(from.URI()),
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},
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Position: loc.Range.Start,
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}
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p := protocol.SignatureHelpParams{
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TextDocumentPositionParams: tdpp,
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}
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s, err := conn.SignatureHelp(ctx, &p)
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if err != nil {
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return err
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}
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if s == nil || len(s.Signatures) == 0 {
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return tool.CommandLineErrorf("%v: not a function", from)
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}
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// there is only ever one possible signature,
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// see toProtocolSignatureHelp in lsp/signature_help.go
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signature := s.Signatures[0]
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fmt.Printf("%s\n", signature.Label)
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if signature.Documentation != "" {
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fmt.Printf("\n%s\n", signature.Documentation)
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}
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return nil
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}
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