Auto merge of #317 - brson:winoverride, r=alexcrichton

Fix overrides for C:\. Fixes #316

src/multirust/override_db.rs

@@ -81,8 +81,8 @@ impl OverrideDB {
         }
 
         let dir = utils::canonicalize_path(dir_unresolved, ntfy!(&notify_handler));
-        let mut path = &*dir;
-        while let Some(parent) = path.parent() {
+        let mut maybe_path = Some(&*dir);
+        while let Some(path) = maybe_path {
             let key = try!(self.path_to_db_key(path, notify_handler));
             if let Some(toolchain) = try!(utils::match_file("override db", &self.0, |line| {
                 if line.starts_with(&key) {
@@ -94,7 +94,7 @@ impl OverrideDB {
                 return Ok(Some((toolchain, path.to_owned())));
             }
 
-            path = parent;
+            maybe_path = path.parent();
         }
 
         Ok(None)

tests/cli-v2.rs

@@ -271,6 +271,34 @@ fn multiple_overrides() {
     });
 }
 
+// #316
+#[test]
+#[cfg(windows)]
+fn override_windows_root() {
+    setup(&|config| {
+        use std::path::{PathBuf, Component};
+
+        let cwd = ::std::env::current_dir().unwrap();
+        let prefix = cwd.components().next().unwrap();
+        let prefix = match prefix {
+            Component::Prefix(p) => p,
+            _ => panic!()
+        };
+
+        // This value is probably "C:"
+        // Really sketchy to be messing with C:\ in a test...
+        let prefix = prefix.as_os_str().to_str().unwrap();
+        let prefix = format!("{}\\", prefix);
+        change_dir(&PathBuf::from(&prefix), &|| {
+            expect_ok(config, &["rustup", "default", "stable"]);
+            expect_ok(config, &["rustup", "override", "add", "nightly"]);
+            expect_stdout_ok(config, &["rustc", "--version"], "hash-n-2");
+            expect_ok(config, &["rustup", "override", "remove"]);
+            expect_stdout_ok(config, &["rustc", "--version"], "hash-s-2");
+        });
+    });
+}
+
 #[test]
 fn change_override() {
     setup(&|config| {