embed + text/template: "incomplete or empty template" error with directory

[eraac]

Depending how you create your *template.Template and where the template is, Execute() can return an error

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

$ go version
go version go1.18.3 darwin/amd64

Does this issue reproduce with the latest release?

Yes -> go version devel go1.19-1ebc983 Thu Jul 7 21:15:48 2022 +0000 darwin/amd64

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

go env Output

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/xxxxx/Library/Caches/go-build"
GOENV="/Users/xxxxx/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/xxxx/core/go/pkg/mod"
GONOPROXY="gitlab.com/xxxx/*"
GONOSUMDB="gitlab.com/xxxx/*"
GOOS="darwin"
GOPATH="/Users/xxxx/core/go"
GOPRIVATE="gitlab.com/xxxx/*"
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.18.3"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/xxxxx/xxxxx/projects/sandbox/bug/go.mod"
GOWORK=""
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 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/7j/8gxzlylj7l140bwg5tclnpmr0000gn/T/go-build449972040=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

setup:

mkdir template
echo "Hello" > template.tpl
echo "Hello" > template/template.tpl

go run main.go

main.go

package main

import (
	"embed"
	"fmt"
	"os"
	"text/template"
)

//go:embed "all:*"
var tpl embed.FS

func main() {
	fmt.Println("WITH DIR+NEW:")
	run(tpl, "template/template.tpl", true)

	fmt.Println("WITH DIR / WITHOUT NEW:")
	run(tpl, "template/template.tpl", false)

	fmt.Println("WITHOUT DIR / WITH NEW:")
	run(tpl, "template.tpl", true)

	fmt.Println("WITHOUT DIR+NEW:")
	run(tpl, "template.tpl", false)
}

func run(fs embed.FS, name string, withNew bool) {
	var (
		t   *template.Template
		err error
	)

	if withNew {
		t, err = template.New(name).ParseFS(fs, name)
	} else {
		t, err = template.ParseFS(fs, name)
	}

	if err != nil {
		fmt.Println(err)
		return
	}

	if err := t.Execute(os.Stdout, nil); err != nil {
		fmt.Println(err)
	}
}

What did you expect to see?

WITH DIR+NEW:
Hello
WITH DIR / WITHOUT NEW:
Hello
WITHOUT DIR / WITH NEW:
Hello
WITHOUT DIR+NEW:
Hello

What did you see instead?

WITH DIR+NEW:
template: template/template.tpl: "template/template.tpl" is an incomplete or empty template
WITH DIR / WITHOUT NEW:
Hello
WITHOUT DIR / WITH NEW:
Hello
WITHOUT DIR+NEW:
Hello

[seankhliao]

from text/template.Template.ParseFiles:

Since the templates created by ParseFiles are named by the base names of the argument files, t should usually have the name of one of the (base) names of the files. If it does not, depending on t's contents before calling ParseFiles, t.Execute may fail. In that case use t.ExecuteTemplate to execute a valid template.

There really is no template called template/template.tpl

Closing as this is working as documented