Auto merge of #16601 - servo:cargoup, r=nox

Update to cargo 0.19.0-nightly (994e552 2017-04-25)

This should be unblocked now: https://github.com/servo/servo/pull/15852#issuecomment-296379226

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python/servo/command_base.py

@@ -257,9 +257,6 @@ class CommandBase(object):
         self.config["tools"].setdefault("system-cargo", False)
         self.config["tools"].setdefault("rust-root", "")
         self.config["tools"].setdefault("cargo-root", "")
-        if not self.config["tools"]["system-cargo"]:
-            self.config["tools"]["cargo-root"] = path.join(
-                context.sharedir, "cargo", self.cargo_build_id())
         self.config["tools"].setdefault("rustc-with-gold", get_env_bool("SERVO_RUSTC_WITH_GOLD", True))
 
         # https://github.com/rust-lang/rust/pull/39754
@@ -283,6 +280,7 @@ class CommandBase(object):
         self.config["android"].setdefault("platform", "android-18")
         self.config["android"].setdefault("target", "arm-linux-androideabi")
 
+        self.set_cargo_root()
         self.set_use_stable_rust(False)
 
     _use_stable_rust = False
@@ -290,6 +288,11 @@ class CommandBase(object):
     _rust_version_is_stable = False
     _cargo_build_id = None
 
+    def set_cargo_root(self):
+        if not self.config["tools"]["system-cargo"]:
+            self.config["tools"]["cargo-root"] = path.join(
+                self.context.sharedir, "cargo", self.cargo_build_id())
+
     def set_use_stable_rust(self, use_stable_rust=True):
         self._use_stable_rust = use_stable_rust
         if not self.config["tools"]["system-rust"]:

python/servo/devenv_commands.py

@@ -233,7 +233,7 @@ class MachCommands(CommandBase):
         commit = json.load(urllib2.urlopen(url))["object"]["sha"]
         filename = path.join(self.context.topdir, "rust-commit-hash")
         with open(filename, "w") as f:
-            f.write(commit)
+            f.write(commit + "\n")
 
         # Reset self.config["tools"]["rust-root"]
         self._rust_version = None
@@ -241,6 +241,22 @@ class MachCommands(CommandBase):
 
         self.fetch()
 
+    @Command('cargoup',
+             description='Update the Cargo version to latest master',
+             category='devenv')
+    def cargoup(self):
+        url = "https://api.github.com/repos/rust-lang/cargo/git/refs/heads/master"
+        commit = json.load(urllib2.urlopen(url))["object"]["sha"]
+        filename = path.join(self.context.topdir, "cargo-commit-hash")
+        with open(filename, "w") as f:
+            f.write(commit + "\n")
+
+        # Reset self.config["tools"]["cargo-root"]
+        self._cargo_build_id = None
+        self.set_cargo_root()
+
+        self.fetch()
+
     @Command('fetch',
              description='Fetch Rust, Cargo and Cargo dependencies',
              category='devenv')