x/tools/gopls: supress analysis/simplifycompositelit on a generated code

[ohir]

gopls version

Build info
----------
golang.org/x/tools/gopls v0.15.3
    golang.org/x/tools/gopls@v0.15.3 h1:zbdOidFrPTc8Bx0YrN5QKgJ0zCjyGi0L27sKQ/bDG5o=
    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@v0.15.0 h1:SernR4v+D55NyBH2QiEQrlBAnj1ECL6AGrA5+dPaMY8=
    golang.org/x/sync@v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
    golang.org/x/telemetry@v0.0.0-20240209200032-7b892fcb8a78 h1:vcVnuftN4J4UKLRcgetjzfU9FjjgXUUYUc3JhFplgV4=
    golang.org/x/text@v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
    golang.org/x/tools@v0.18.1-0.20240412183611-d92ae0781217 h1:uH9jJYgeLCvblH0S+03kFO0qUDxRkbLRLFiKVVDl7ak=
    golang.org/x/vuln@v1.0.1 h1:KUas02EjQK5LTuIx1OylBQdKKZ9jeugs+HiqO5HormU=
    honnef.co/go/tools@v0.4.6 h1:oFEHCKeID7to/3autwsWfnuv69j3NsfcXbvJKuIcep8=
    mvdan.cc/gofumpt@v0.6.0 h1:G3QvahNDmpD+Aek/bNOLrFR2XC6ZAdo62dZu65gmwGo=
    mvdan.cc/xurls/v2@v2.5.0 h1:lyBNOm8Wo71UknhUs4QTFUNNMyxy2JEIaKKo0RWOh+8=
go: go1.22.1

go env

# empty items skipped
GOARCH='amd64'
GOBIN='/Path/To/bin'
GOCACHE='/Volumes/TEMP/gocache'
GOENV='/Path/To/go/env'
GOHOSTARCH='amd64'
GOHOSTOS='darwin'
GOMODCACHE='/Path/To/src/pkg/mod'
GONOPROXY='example.com'
GONOSUMDB='example.com'
GOOS='darwin'
GOPATH='/Path/To/src'
GOPRIVATE='example.com'
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/Path/To/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR='/Path/To/TEMP/go'
GOTOOLCHAIN='auto'
GOTOOLDIR='/Path/To/go/pkg/tool/darwin_amd64'
GOVCS='public:git'
GOVERSION='go1.22.3'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/Path/To/project/module/go.mod'
GOWORK='/Path/To/project/go.work'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/Path/To/TEMP/go/go-build1959820345=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

I have code that has been generated with fmt.Printf("%#v",somestruct) in files that are being properly
marked as such with // Code generated with somegen DO NOT EDIT. header in the first line.
Gopls errornously suggests to simplify Printf produced literals polluting the "Problems"
pane in the IDE (while properly refusing to format file on save).

Repr:

// Code generated with somegen DO NOT EDIT.
package main

import "fmt"

type ProofOB struct{
	A [][]string
}
func main(){
	// x := ProofOB{A: [][]string{{"some value"}}}
	x := ProofOB{A: [][]string{[]string{"some value"}}}
	fmt.Printf("%#v\n",x)
}
// Result: main.ProofOB{A:[][]string{[]string{"some value"}}}

What did you see happen?

hundreds of:

[{
	"resource": "[...cut...]/generated_test.go",
	"owner": "_generated_diagnostic_collection_name_#4",
	"code": {
		"value": "default",
		"target": {
			"$mid": 1,
			"path": "/golang.org/x/tools/gopls/internal/analysis/simplifycompositelit",
			"scheme": "https",
			"authority": "pkg.go.dev"
		}
	},
	"severity": 4,
	"message": "redundant type from array, slice, or map composite literal",
	"source": "simplifycompositelit",
	"startLineNumber": 2997,
	"startColumn": 104,
	"endLineNumber": 2997,
	"endColumn": 212,
	"tags": [
		1
	]
}]

What did you expect to see?

I expected Gopls to know from the "Code generated" header that code here CAN NOT be simplified.

Editor and settings

"gopls": {  
        "ui.diagnostic.analyses": {
            "simplifycompositelit": true,
        },
        "formatting.gofumpt": true,
    },

Note: simplifycompositelit is by default true, but I had to have set it to false as a workaround now.

Logs

No response

[findleyr]

Agreed, we should disable all "simplifiers" on generated code.

[idnandre]

Can i take this one?

[timothy-king]

@idnandre Sure. We won't assign this to you, but if you chip in and send CLs, we will review them. (Take a look at https://go.dev/doc/contribute if you haven't before.)

You probably want to wait for gopls to require a Go Version >= 1.21 e.g. for #65917 to close. After 1.21 is available the function ast.IsGenerated will be available.

(You technically don't have to wait, but everything becomes about 4x harder. It requires create a library with built tags that makes sense both with and without go 1.21, and interprets "IsGenerated" in the correct direction whenever you use it when ast.IsGenerated is not available. Or duplicates the needed code. And write tests both before and after 1.21.)

[idnandre]

Hi @timothy-king
Okay, I will work on it.

Thank you.

[gopherbot]

Change https://go.dev/cl/598835 mentions this issue: gopls: add skipped gopls analysis simplifycompositelit if its on generated code