env var API could be better

[emidoots]

std.os.getenv doesn't work on Windows (see #10952) but I suspect it's what people will find first.

You should probably be using std.process.getEnvVarOwned but:

1. It's a mouthful, I doubt it'd be clear to a new user of Zig that's the right API to use.
2. It's usage feels a bit obtuse because of the fact that it returns an error in the case of no such env var:

zig/lib/std/child_process.zig

Lines 845 to 853 in a4df443

	var free_path = true;
	const PATH = process.getEnvVarOwned(self.allocator, "PATH") catch |err| switch (err) {
	error.EnvironmentVariableNotFound => blk: {
	free_path = false;
	break :blk "";
	},
	else => |e| return e,
	};
	defer if (free_path) self.allocator.free(PATH);

Solution

I'm not sure how to fix the naming issue, or if that is possible.

Perhaps we could change the function signature to not return an error for EnvironmentVariableNotFound though? Then usage would be just:

const PATH = try process.getEnvVarOwned(self.allocator, "PATH");
if (PATH) self.allocator.free(PATH);

And orelse usage would then just be:

const path = PATH orelse "";

Thoughts?

[marler8997]

Maybe moving getenv to something like std.posix or std.os.posix would help make things more clear?

[emidoots]

Good point, that would've definitely helped me!

[tristanisham]

There is std.os.getenvW(0 which follows the sematic way Windows specific functions are highlighted. I'm not sure if the WTF-16 limitation will impact user's looking for ENVs on Windows as it isn't my platform franca.