x/tools/gopls: get signature when cursor is over the function name

[crazyhulk]

gopls version

Build info

golang.org/x/tools/gopls v0.16.1
golang.org/x/tools/gopls@v0.16.1 h1:1hO/dCeUvjEYx3V0rVvCtOkwnpEpqS29paE+Jw4dcAc=
github.com/BurntSushi/toml@v1.2.1 h1:9F2/+DoOYIOksmaJFPw1tGFy1eDnIJXg+UHjuD8lTak=
github.com/google/go-cmp@v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
golang.org/x/exp/typeparams@v0.0.0-20221212164502-fae10dda9338 h1:2O2DON6y3XMJiQRAS1UWU+54aec2uopH3x7MAiqGW6Y=
golang.org/x/mod@v0.18.0 h1:5+9lSbEzPSdWkH32vYPBwEpX8KwDbM52Ud9xBUvNlb0=
golang.org/x/sync@v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
golang.org/x/telemetry@v0.0.0-20240607193123-221703e18637 h1:3Wt8mZlbFwG8llny+t18kh7AXxyWePFycXMuVdHxnyM=
golang.org/x/text@v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
golang.org/x/tools@v0.22.1-0.20240628205440-9c895dd76b34 h1:Kd+Z5Pm6uwYx3T2KEkeHMHUMZxDPb/q6b1m+zEcy62c=
golang.org/x/vuln@v1.0.4 h1:SP0mPeg2PmGCu03V+61EcQiOjmpri2XijexKdzv8Z1I=
honnef.co/go/tools@v0.4.7 h1:9MDAWxMoSnB6QoSqiVr7P5mtkT9pOc1kSxchzPCnqJs=
mvdan.cc/gofumpt@v0.6.0 h1:G3QvahNDmpD+Aek/bNOLrFR2XC6ZAdo62dZu65gmwGo=
mvdan.cc/xurls/v2@v2.5.0 h1:lyBNOm8Wo71UknhUs4QTFUNNMyxy2JEIaKKo0RWOh+8=
go: go1.21.0

go env

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/zx/.cache/go-build'
GOENV='/home/zx/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/zx/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/zx/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.21.0'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/home/zx/workspace/go/tools/gopls/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2830052148=/tmp/go-build -gno-record-gcc-switches'

What did you do?

I cannot get function signatures without the parentheses when use lsp."textDocument/signatureHelp" when I make a code snippet plugin for neovim.

cmp-sign

What did you see happen?

Get nil by exec lua vim.lsp.buf.signature_help() in the neovim when cursor over the function name.

What did you expect to see?

We prefere to use "." to trigger a code complete menu, we also need the ability to retrieve function signatures when cursor over the function name.

I have made a pull request to fix this.

Editor and settings

nvim, it works well.

Logs

No response

[gabyhelp]

Related Issues and Documentation

• x/tools/gopls: show signature help when typing a struct as an argument to a function? #42149 (closed)
• x/tools/gopls: Wrongly received json information of other nvim plugins #55892 (closed)
• x/tools/gopls: extract function action doesn't work if the first line is a comment #54816 (closed)
• x/tools/gopls: add gopls.package_info command #51490
• x/tools/gopls: add method documentation & jump to page source to hovered type. #66721 (closed)
• x/tools/gopls: superfluous {} added to first completion result for named struct type #36655 (closed)
• x/tools/gopls: snippets do not replace triggering preamble #59508 (closed)
• x/tools/gopls: Completion not working in modules with "vendor" as their name #54071 (closed)
• x/tools/gopls: add gopls.package_symbols command #51492
• x/tools/gopls: textEdit calculation wrong. #57384 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[findleyr]

Thanks, it seems reasonable to support this, and agree that it is a good help-wanted issue. Thanks for the contribution, we'll review your CL.

[adonovan]

I agree that the feature seems like a reasonable interpretation of SignatureHelp and its SignatureInformation result type, which represents "the signature of something callable".

[crazyhulk]

I agree that the feature seems like a reasonable interpretation of SignatureHelp and its SignatureInformation result type, which represents "the signature of something callable".

/**

• Signature help represents the signature of something
• callable. There can be multiple signature but only one
• active and only one active parameter.
  */

Callable, not calling?

" Signature help represents the signature of something callable." which refers to the entire set of method, sel, function, etc.

Gopls provides tremendous help while we write code, consider the following situation:

func foo(a, b int) int {
}

foo.

I want a complete menu here, and I must call foo.
In this situation, if signature help is provided only after I’ve completed writing the function, it’s no longer useful.

In other words, we should provide function signatures for everything that is callable, not just for functions that are already being called.

[adonovan]

We agree. :-)