os: TempDir mistakenly removes \ in C:\

[alexbrainman]

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

go version devel +26985ed4a5 Sat Dec 15 04:18:21 2018 +0000 windows/amd64

Does this issue reproduce with the latest release?

Yes.

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

go env Output

set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\Alex\AppData\Local\go-build
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=c:\users\alex\dev
set GOPROXY=
set GORACE=
set GOROOT=c:\users\alex\dev\go
set GOTMPDIR=
set GOTOOLDIR=c:\users\alex\dev\go\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\Alex\AppData\Local\Temp\go-build672692694=/tmp/go-build -gno-record-gcc-switches

What did you do?

I set my TMP directory to Z:\

I used this command:

set TMP=Z:\

Then I built and run this program https://play.golang.org/p/8FXtRPXiQar

What did you expect to see?

Z:\

What did you see instead?

Z:

My comments

Removing last \ is wrong, because Z:\ is root directory on Z:, while Z: is current directory on Z:.

Probably, not common to use root directory for TMP. But, if setup this way, I can see how os.TempDir will bring confusion and chaos in my program.

Alex

[gopherbot]

Change https://golang.org/cl/154384 mentions this issue: os: adjust TempDir for Z:\