Cannot ReadFile when using embed.FS on a directory

[bravecorvus]

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

$ go version go1.16.2 darwin/amd64

Does this issue reproduce with the latest release?

Yes

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

go env Output

GO111MODULE="on"
GOARCH="amd64"
GOBIN="/Users/andrewlee/go/bin"
GOCACHE="/Users/andrewlee/Library/Caches/go-build"
GOENV="/Users/andrewlee/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/andrewlee/go/pkg/mod"
GONOPROXY="*.amazonaws.com/v1/repos"
GONOSUMDB="*.amazonaws.com/v1/repos"
GOOS="darwin"
GOPATH="/Users/andrewlee/go"
GOPRIVATE="*.amazonaws.com/v1/repos"
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/Cellar/go/1.16.2/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.16.2/libexec/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.16.2"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="0"
GOMOD="/Users/andrewlee/Projects/TestProjects/test_bindata/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 -arch x86_64 -m64 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/3k/x98sh83s31nb6kl86555q0c80000gn/T/go-build307906134=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Created a simple example to see how I can replace https://github.com/gilgameshskytrooper/go-bindata with native 1.16 file embed functionality.

root/
├── files/
│   ├── hello.txt
└── main.go
└── go.mod

hello.txt

Hello World

go.mod

module test_bindata

go 1.16

main.go

package main

import (
	"embed"
	_ "embed"
	"fmt"
)

// Also tried "files"
// go:embed files/*
var embedFS embed.FS

func main() {
        // Also tried "hello.txt", "/files/hello.txt", "./files/hello.txt"
	fileData, err := embedFS.ReadFile("files/hello.txt")
	if err != nil {
		panic(err)
	}
	fmt.Println("string(fileData): ", string(fileData))
}

Most examples I see specify how to use the go:embed directive to point to a particular file, and reading that particular file using ReadFile(). Or defining a directory in the go:embed directive, and using http.FS() to host that folder. However, I could not find an example of using // go:embed files/* to embed the entire directory, then trying to directly read a file located inside that directory using ReadFile(). Therefore, I wanted to know if this is even possible.

What did you expect to see?

Successful file read.

What did you see instead?

panic: open files/hello.txt: file does not exist

[seankhliao]

Duplicate of #43698

[bravecorvus]

Doesn't seem like the same issue to me. #43698 seems to be referring to a linting problem. Mine is pointing to the behavior of ReadFile().

[seankhliao]

Yes, and the proposed rule would catch the problem with your code: space in // go:embed

[bravecorvus]

Gocha. Thanks