os: CopyFS overwrites existing file in destination. #68895
Description
Go version
go version go1.23.0 darwin/amd64
Output of go env in your module/workspace:
GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/Users/user/Library/Caches/go-build'
GOENV='/Users/user/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT='rangefunc'
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/user/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/user/go'
GOPRIVATE=''
GOPROXY='https://goproxy.cn,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/darwin_amd64'
GOVCS=''
GOVERSION='go1.23.0'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/user/Library/Application Support/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/dev/null'
GOWORK=''
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=/var/folders/4v/g652j2zn37lg22crrdwmcqdm0000gn/T/go-build1911013595=/tmp/go-build -gno-record-gcc-switches -fno-common'What did you do?
package main
import (
"fmt"
"os"
)
func main() {
os.Mkdir("src", 0o777)
os.WriteFile("src/file", ([]byte)("src"), 0o666)
os.Mkdir("dest", 0o777)
os.WriteFile("dest/file", ([]byte)("dest"), 0o666)
os.CopyFS("dest", os.DirFS("src")) // dest/file should not be overwritten.
file, _ := os.ReadFile("dest/file")
fmt.Printf("%s", file)
}The doc of os.CopyFS says: CopyFS will not overwrite existing files, and returns an error if a file name in fsys already exists in the destination.. So dest/file should not be overwritten.
What did you see happen?
src
What did you expect to see?
dest