Panic on already generated godoc

[krzwiatrzyk]

My code:

package handler

import (
	"gmod/pkg/version"
	"net/http"

	"github.com/autometrics-dev/autometrics-go/prometheus/autometrics"
	"github.com/gin-gonic/gin"
)

//go:generate autometrics
//autometrics:inst
func (h *Handler) VersionHandler(ctx *gin.Context) {
	defer autometrics.Instrument(autometrics.PreInstrument(autometrics.NewContext(
		nil,
		autometrics.WithConcurrentCalls(true),
		autometrics.WithCallerName(true),
	)), nil) //autometrics:defer

	ctx.JSON(http.StatusOK, gin.H{
		"version": version.Version,
	})
}

First run of go generate ./... runs smooth, properly generates docs and instruments code. Executing it second time causes panic:

❯ go generate ./...
panic: runtime error: slice bounds out of range [:-1]

goroutine 1 [running]:
github.com/autometrics-dev/autometrics-go/internal/generate.cleanUpAutometricsComments({{{0x911459, 0x3}, {0x0, 0x0}, {0x0, 0x0}, 0x1, 0x1, 0x0}, {0x0, ...}, ...}, ...)
        /home/krzwiatrzyk/go/pkg/mod/github.com/autometrics-dev/[email protected]/internal/generate/documentation.go:43 +0x691
github.com/autometrics-dev/autometrics-go/internal/generate.walkFuncDeclaration(0xc000166000, 0xc000188000, {0xc0000322da?, 0x8cd560?})
        /home/krzwiatrzyk/go/pkg/mod/github.com/autometrics-dev/[email protected]/internal/generate/generate.go:145 +0x29b
github.com/autometrics-dev/autometrics-go/internal/generate.GenerateDocumentationAndInstrumentation.func1({0x9c6da0?, 0xc000188000?})
        /home/krzwiatrzyk/go/pkg/mod/github.com/autometrics-dev/[email protected]/internal/generate/generate.go:100 +0x4b
github.com/dave/dst.inspector.Visit(0xc000182240, {0x9c6da0?, 0xc000188000?})
        /home/krzwiatrzyk/go/pkg/mod/github.com/dave/[email protected]/walk.go:341 +0x31
github.com/dave/dst.Walk({0x9c82c0?, 0xc000182240?}, {0x9c6da0?, 0xc000188000?})
        /home/krzwiatrzyk/go/pkg/mod/github.com/dave/[email protected]/walk.go:52 +0x68
github.com/dave/dst.walkDeclList({0x9c82c0, 0xc000182240}, {0xc000132e60?, 0x2, 0x50?})
        /home/krzwiatrzyk/go/pkg/mod/github.com/dave/[email protected]/walk.go:38 +0x69
github.com/dave/dst.Walk({0x9c82c0?, 0xc000182240?}, {0x9c6d60?, 0xc00011ef70?})
        /home/krzwiatrzyk/go/pkg/mod/github.com/dave/[email protected]/walk.go:321 +0x173e
github.com/dave/dst.Inspect(...)
        /home/krzwiatrzyk/go/pkg/mod/github.com/dave/[email protected]/walk.go:353
github.com/autometrics-dev/autometrics-go/internal/generate.GenerateDocumentationAndInstrumentation({{{0x911459, 0x3}, {0x0, 0x0}, {0x0, 0x0}, 0x1, 0x1, 0x0}, {0x0, ...}, ...}, ...)
        /home/krzwiatrzyk/go/pkg/mod/github.com/autometrics-dev/[email protected]/internal/generate/generate.go:110 +0x2c5
github.com/autometrics-dev/autometrics-go/internal/generate.TransformFile({{{0x911459, 0x3}, {0x0, 0x0}, {0x0, 0x0}, 0x1, 0x1, 0x0}, {0x0, ...}, ...}, ...)
        /home/krzwiatrzyk/go/pkg/mod/github.com/autometrics-dev/[email protected]/internal/generate/generate.go:54 +0x2e8
main.main()
        /home/krzwiatrzyk/go/pkg/mod/github.com/autometrics-dev/[email protected]/cmd/autometrics/main.go:77 +0x1c5
pkg/handler/version.go:36: running "autometrics": exit status 2

[krzwiatrzyk]

Also:

• doc examples on autometrics website references bad pkg url (autometrics "github.com/autometrics-dev/autometrics-go/pkg/autometrics/otel <- not exist)

[gagbo]

Hello, and thanks for the report.

I think I hit this issue once but since I have a test for this I thought I only got unlucky when I instrumented things. Apparently not, I'll look into this today.

And thanks for the doc example, we changed the name of the import to be more telling and I missed a few places!