Environment variables are not retrieved properly on Windows

[dschafhauser]

Bug Description:

Only environment variables which are entirely lowercase will be resolved properly by EnvVariablesServerImpl.

Steps to Reproduce:

1. Set some environment variables like this:

setx UPPER_VAR UPPER_VAR_value
setx lower_var lower_var_value

2. Create small example extension:

@inject(EnvVariablesServer)
private readonly envVariablesServer: EnvVariablesServer;

public example(): void {
	this.envVariablesServer
		.getValue("UPPER_VAR")
		.then((e: EnvVariable) =>
			console.log(`${e.name} = ${e.value}`)
		);
	
	this.envVariablesServer
		.getValue("lower_var")
		.then((e: EnvVariable) =>
			console.log(`${e.name} = ${e.value}`)
		);
}

3. Executing yields the following output:

TypeError: Cannot read property 'name' of null
lower_var = lower_var_value

Possible fix

Lookup of variables on Windows is always lowercase:

theia/packages/core/src/node/env-variables/env-variables-server.ts

Lines 45 to 50 in 751a3d7

	async getValue(key: string): Promise<EnvVariable | undefined> {
	if (isWindows) {
	key = key.toLowerCase();
	}
	return this.envs[key];
	}

However, the population of envs is with the actual names of the variables which might have arbitrary case:

theia/packages/core/src/node/env-variables/env-variables-server.ts

Lines 30 to 35 in 751a3d7

	constructor() {
	const prEnv = process.env;
	Object.keys(prEnv).forEach((key: string) => {
	this.envs[key] = { 'name': key, 'value': prEnv[key] };
	});
	}

See discussion on Spectrum:
https://spectrum.chat/theia/general/how-to-resolve-environment-variables-in-a-launch-json-configuration~59464670-cb02-4b9d-8f05-084ffe96753f?m=MTU5MTM2NjIxODMwOA==

Additional Information

• Operating System: Windows 10 (1809)
• Theia Version: 1.1.0