Doc: improve documentation for working with template files

[bigon]

What version of Go, VS Code & VS Code Go extension are you using?

Version Information

• Run go version to get version of Go from the VS Code integrated terminal.
  • go version go1.23.4 linux/amd64
• Run gopls -v version to get version of Gopls from the VS Code integrated terminal.
  • v0.17.1
• Run code -v or code-insiders -v to get version of VS Code or VS Code Insiders.
  • 1.96.2
• Check your installed extensions to get the version of the VS Code Go extension
  • 0.44.0
• Run Ctrl+Shift+P (Cmd+Shift+P on Mac OS) > Go: Locate Configured Go Tools command.

  • Tools Configuration

Environment

GOBIN: undefined
toolsGopath:
gopath: /home/bigon/go
GOROOT: /usr/lib/go-1.23
PATH: /home/bigon/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games

Tools

go:	/usr/bin/go: go version go1.23.4 linux/amd64

gopls:	/home/bigon/go/bin/gopls	(version: v0.17.1 built with go: go1.23.4)
gotests:	not installed
gomodifytags:	not installed
impl:	not installed
goplay:	not installed
dlv:	/usr/bin/dlv	(version: undefined built with go: go1.23.4)
staticcheck:	/home/bigon/go/bin/staticcheck	(version: v0.5.1 built with go: go1.23.4)

Go env

Workspace Folder (thanos-receivers): /home/bigon/Boulot//code/thanos-receivers

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/bigon/.cache/go-build'
GOENV='/home/bigon/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/bigon/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/bigon/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/lib/go-1.23'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/lib/go-1.23/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.23.4'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/bigon/.config/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/dev/null'
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-build2302377950=/tmp/go-build -gno-record-gcc-switches'

Share the Go related settings you have added/edited

Default config

Describe the bug

No syntax highlighting for gotmpl

I'm expecting to have some colors and highlighting

Steps to reproduce the behavior:

1. Install the vscode-go extension
2. Open a gotmpl file
3. No syntax highlighting for gotmpl

Screenshots or recordings

If applicable, add screenshots or recordings to help explain your problem.

[bigon]

I also see the following error in the gopls server output:

[Error - 16:49:00] Request textDocument/documentSymbol failed.
Error: name must not be falsy
    at Function.validate (file:///usr/share/code/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:109:33647)
    at new Gd (file:///usr/share/code/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:109:33936)
    at asDocumentSymbol (/home/bigon/.vscode/extensions/golang.go-0.44.0/dist/goMain.js:14573:22)
    at convertBatch (/home/bigon/.vscode/extensions/golang.go-0.44.0/dist/goMain.js:12968:23)
    at Object.map (/home/bigon/.vscode/extensions/golang.go-0.44.0/dist/goMain.js:12976:19)
    at Object.asDocumentSymbols (/home/bigon/.vscode/extensions/golang.go-0.44.0/dist/goMain.js:14570:22)
    at _provideDocumentSymbols (/home/bigon/.vscode/extensions/golang.go-0.44.0/dist/goMain.js:18861:64)
    at uI.provideDocumentSymbols (file:///usr/share/code/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:138:126457)

[findleyr]

Hi, are you setting the "templateExtensions" gopls setting?
https://github.com/golang/tools/blob/master/gopls/doc/settings.md#templateextensions-string

Without this set, VS Code will not recognize go template files.

[bigon]

Hello,

For what I can see, the file with .gotmpl are already recognized as a go template

For I added the following and it's the same issue

    "gopls": {

        "templateExtensions": [
            "gotmpl",
        ]
    }

[findleyr]

Thanks @bigon: are you still not seeing syntax highlighting after that change?

You may also need to add: "semanticTokens": true.

[bigon]

"semanticTokens": true to true is showing some color, yes

[findleyr]

Thank you. Reclassifying this as a documentation bug, to improve our (nearly nonexistent) documentation for working with template files.

[bigon]

Shouldn't semanticTokens be set to true by default?