Cannot pass environment variable that is already defined in shell's rc file.

[saml]

• VSCode Version: 0.10.11
• OS Version: Ubuntu 14.04

Steps to Reproduce:

1. Export a variable in your default shell (~/.zlogin for zsh; ~/.bash_login for bash, for example. You can use .bashrc as well).

   export FOOBAR="1"

2. Pass different value of the same variable to VSCode.

   FOOBAR=2 code .

3. VSCode uses value defined for login shell, not current session:

Help > Toggle Developer Tools. And in Console, process.env.FOOBAR gives "1" when I expect "2".

It looks like VSCode executes default shell as login shell again before launching the program UI.

Being able to pass different values for existing environment variables greatly helps writing/testing extensions.

Related discussion: microsoft/vscode-go#220 (comment)

strace example:

$ strace -E GOPATH=1 -E FOOBAR=2 -s 1000000 -e verbose=execve -e abbrev=none ./.build/electron/electron  .
execve("./.build/electron/electron", ["./.build/electron/electron", "."], [... "GOPATH=1", ...]) # What I expected
...
read(62, "...\nGOPATH=/home/saml/go\n....")  # What is this?
...

[saml]

Looks like this is the place that resets envvars:

https://github.com/Microsoft/vscode/blob/25ce394231a63cad030c804460bd957a1102d14e/src/vs/workbench/electron-main/main.ts#L252-L256

// On some platforms we need to manually read from the global environment variables
// and assign them to the process environment (e.g. when doubleclick app on Mac)
getUserEnvironment()
    .then(userEnv => {
        assign(process.env, userEnv);

https://github.com/Microsoft/vscode/blob/25ce394231a63cad030c804460bd957a1102d14e/src/vs/base/node/env.ts#L22

         let child = cp.spawn(process.env.SHELL, ['-ilc', 'env'], {

Do we really need to execute $SHELL -c env there? Can we assume or check if env command exists and execute it?

# intuitive behavior: variable GOPATH can be overwritten
$ GOPATH=1 env |grep GOPATH
GOPATH=1

# variable cannot be overwritten. 
$ GOPATH=1 $SHELL -c env |grep GOPATH
GOPATH=/home/saml/go

Or, getUserEnvironment() in main.ts should only be called if it's not invoked from terminal:

import tty = require('tty');
if (!tty.isatty(process.stdout)) {
  getUserEnvirionment() .....
}

[Tyriar]

@bpasero @joaomoreno any comment on why this is used over process.env? I just fixed an issue with it recently because multi-line variables weren't working.

[joaomoreno]

Duplicate of #1033, fixed already.