go ignoring vendor directory - windows

Question

Everything I read about the vendor directory gives me the understanding that if I have a directory:
$GOPATH/src/vendor
And put my dependencies in there (I am using godeps), when doing go run, go should check in that directory first.
If I run my code in a Docker image I have, this works fine. However now that I try to run the same code on my Windows machine, go simply ignores the vendor/ directory, and fails to find the dependencies.
What am I doing wrong?
main.go:7:2: cannot find package "gopkg.in/alecthomas/kingpin.v2" in any of:
C:\Go\src\gopkg.in\alecthomas\kingpin.v2 (from $GOROOT)
C:\Users\js\dev\my_project\rest\src\gopkg.in\alecthomas\kingpin.v2 (from $GOPATH)
C:\Users\js\dev\go\src\gopkg.in\alecthomas\kingpin.v2
Is the output when I try to do:
go run main.go
A directory vendor/ exists in this directory.
go version go1.7 windows/amd64
The exact commands I run (in windows cmd.exe)
> cd C:\Users\js\dev\my_project\rest\
> set GOPATH=C:\Users\js\dev\my_project\rest\;c:\Users\js\dev\go
> cd src
> dir
...
2016-09-01 23:20 2 923 main.go
...
2016-09-03 01:27 <DIR> vendor
> go run main.go

Answer 1

The reason this did not work is because you are not supposed to put any code directly into the $GOPATH/src/ directory.
The solution is to put your project into a sub-directory like so:
$GOPATH/src/app/*.go

Answer 2

Seems your GOPATH is incorrect?
The GOPATH should specify the location of your workspace i.e. directory containing src, pkg and bin directories at its root.
Try doing
set GOPATH=C:\Users\js\dev\my_project\rest\;c:\Users\js\dev\go
More details at: https://golang.org/doc/code.html

Answer 3

The first thing to understand is that godep save is simply copying dependencies from your $GOPATH to a vendor directory inside your project.
You will have to go get your dependencies first. After you have them in $GOPATH, you can do a godep save to copy the current version to your project, and be assured that even if the version in $GOPATH changes, you will have a fixed version in your project until you explicitly change it via godep.
So, if I have a $GOPATH of /home/me/go_workspace, and a project called $GOPATH/src/github.com/project_x with a dependency of github.com/you/xyz, then I would do go get github.com/you/xyz, and godep save from within my project directory. This would create a vendor folder with the dependency at its current commit inside.