embed: failed to build source file contains string "/*"

[zhuah]

What version of Go are you using (go version)?

$ go version
go version devel +b116404444 Wed Dec 23 17:31:18 2020 +0000 darwin/amd64

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/zhuah/Library/Caches/go-build"
GOENV="/Users/zhuah/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/zhuah/go/pkg/mod"
GOOS="darwin"
GOPATH="/Users/zhuah/go"
GOPROXY="https://goproxy.cn,direct"
GOROOT="/usr/local/Cellar/gotip"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/gotip/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="devel +b116404444 Wed Dec 23 17:31:18 2020 +0000"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/zhuah/Projects/playground/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/8n/mb3y_4bj1xv4q9sdmgjqdx_c0000gn/T/go-build314626058=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

sample code here:

package main

import (
	_ "embed"
	"strings"
)

var s = strings.ToUpper("test/*")

//go:embed main.go
var content string

func main() {
	_ = content
}

when i build it, the compile print errors:

# github.com/playground/embedtest
./main.go:10:3: invalid go:embed: build system did not supply embed configuration

if i comment var s = strings.ToUpper("test/*") or replace /* with any other strings, the compilation succeed.

What did you expect to see?

What did you see instead?

[seankhliao]

I don't think it's just the presence of /*, it's also where it is. The following errors:

package main

import _ "embed"

var s = "/*"

//go:embed main.go
var content string

func main() {}

But this works:

package main

import _ "embed"

//go:embed main.go
var content string

var s = "/*"

func main() {}

[gopherbot]

Change https://golang.org/cl/280332 mentions this issue: go/build: skip string while findEmbed

[toothrot]

@rsc Can you take a look at https://golang.org/cl/280332?