x/build/cmd/release: windows installer propose to remove detected old version in installation directory

[techtonik]

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

go1.6.3.windows-386.msi

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

set GOROOT=C:\Program Files\Go
set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_386
set GO15VENDOREXPERIMENT=1

What did you do?

Run installer go1.6.3.windows-386.msi, it didn't detect existing 1.6.2 installation, so I thought that maybe it is a feature to run multiple versions of Go side by side. Pointed it to existing C:\Program Files\Go installation.

What did you expect to see?

Expected it at least to warn about non-empty directory, then tell me what is he going to do with it:

1. remove
2. blend its files inside
3. fail

What did you see instead?

I see request for administration privileges to continue installation.

[0xmohit]

The current instructions mention:

If you are upgrading from an older version of Go you must first remove the existing version.

[techtonik]

@0xmohit yea, I saw that, but many open source projects automate this in installer - for example VLC installer detects old installation and proposes several actions:

https://github.com/videolan/vlc/tree/master/extras/package/win32

[bradfitz]

Related: #16305

We don't have a Windows installer expert on the team. Any help is wanted.

[iwdgo]

Warning as displayed to install Go 1.12beta1 seems to solve the issue:

[bradfitz]

Thanks. Will close then.