Rollup merge of #22727 - alexcrichton:prep-env, r=aturon

This commit moves `std::env` away from the `std::old_io` error type as well as
the `std::old_path` module. Methods returning an error now return `io::Error`
and methods consuming or returning paths use `std::path` instead of
`std::old_path`. This commit does not yet mark these APIs as `#[stable]`.

This commit also migrates `std::old_io::TempDir` to `std::fs::TempDir` with
essentially the exact same API. This type was added to interoperate with the new
path API and has its own `tempdir` feature.

Finally, this commit reverts the deprecation of `std::os` APIs returning the old
path API types. This deprecation can come back once the entire `std::old_path`
module is deprecated.

[breaking-change]

src/test/run-pass/env-home-dir.rs

@@ -9,13 +9,14 @@
 // except according to those terms.
 
 use std::env::*;
+use std::path::PathBuf;
 
 #[cfg(unix)]
 fn main() {
     let oldhome = var("HOME");
 
     set_var("HOME", "/home/MountainView");
-    assert!(home_dir() == Some(Path::new("/home/MountainView")));
+    assert!(home_dir() == Some(PathBuf::new("/home/MountainView")));
 
     remove_var("HOME");
     if cfg!(target_os = "android") {

src/test/run-pass/issue-15149.rs

@@ -1,5 +1,3 @@
-// no-prefer-dynamic
-
 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
@@ -10,12 +8,15 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::slice::SliceExt;
-use std::old_io::{fs, USER_RWX};
-use std::process;
+// no-prefer-dynamic
+
+#![feature(fs, process, env, path, rand)]
+
 use std::env;
-use std::old_path::BytesContainer;
+use std::fs;
+use std::process;
 use std::rand::random;
+use std::str;
 
 fn main() {
     // If we're the child, make sure we were invoked correctly
@@ -34,21 +35,20 @@ fn main() {
 fn test() {
     // If we're the parent, copy our own binary to a new directory.
     let my_path = env::current_exe().unwrap();
-    let my_dir  = my_path.dir_path();
+    let my_dir  = my_path.parent().unwrap();
 
     let random_u32: u32 = random();
-    let child_dir = Path::new(my_dir.join(format!("issue-15149-child-{}",
-                                                  random_u32)));
-    fs::mkdir(&child_dir, USER_RWX).unwrap();
+    let child_dir = my_dir.join(&format!("issue-15149-child-{}", random_u32));
+    fs::create_dir(&child_dir).unwrap();
 
-    let child_path = child_dir.join(format!("mytest{}",
-                                            env::consts::EXE_SUFFIX));
+    let child_path = child_dir.join(&format!("mytest{}",
+                                             env::consts::EXE_SUFFIX));
     fs::copy(&my_path, &child_path).unwrap();
 
     // Append the new directory to our own PATH.
     let path = {
         let mut paths: Vec<_> = env::split_paths(&env::var_os("PATH").unwrap()).collect();
-        paths.push(child_dir.clone());
+        paths.push(child_dir.to_path_buf());
         env::join_paths(paths.iter()).unwrap()
     };
 
@@ -58,9 +58,9 @@ fn test() {
 
     assert!(child_output.status.success(),
             format!("child assertion failed\n child stdout:\n {}\n child stderr:\n {}",
-                    child_output.stdout.container_as_str().unwrap(),
-                    child_output.stderr.container_as_str().unwrap()));
+                    str::from_utf8(&child_output.stdout).unwrap(),
+                    str::from_utf8(&child_output.stderr).unwrap()));
 
-    fs::rmdir_recursive(&child_dir).unwrap();
+    fs::remove_dir_all(&child_dir).unwrap();
 
 }

src/test/run-pass/issue-16272.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::old_io::{process, Command};
+use std::process::Command;
 use std::env;
 
 fn main() {
@@ -22,10 +22,8 @@ fn main() {
 }
 
 fn test() {
-    let status = Command::new(env::current_exe().unwrap())
+    let status = Command::new(&env::current_exe().unwrap())
                          .arg("foo").arg("")
-                         .stdout(process::InheritFd(1))
-                         .stderr(process::InheritFd(2))
                          .status().unwrap();
     assert!(status.success());
 }

src/test/run-pass/issue-20091.rs

@@ -8,14 +8,19 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// ignore-windows currently windows requires UTF-8 for spawning processes
-
-use std::old_io::Command;
-use std::env;
-
+#[cfg(unix)]
 fn main() {
+    use std::process::Command;
+    use std::env;
+    use std::os::unix::prelude::*;
+    use std::ffi::OsStr;
+
     if env::args().len() == 1 {
-        assert!(Command::new(env::current_exe().unwrap()).arg(b"\xff")
+        assert!(Command::new(&env::current_exe().unwrap())
+                        .arg(<OsStr as OsStrExt>::from_bytes(b"\xff"))
                         .status().unwrap().success())
     }
 }
+
+#[cfg(windows)]
+fn main() {}