Add an optional --debug-mozjs argument to mach build that enables a non-optimized, debug build of mozjs and rust-mozjs. Update the Cargo snapshot to enable new feature support.

python/servo/bootstrap_commands.py

@@ -108,7 +108,7 @@ class MachCommands(CommandBase):
 
         tgz_file = "cargo-nightly-%s.tar.gz" % host_triple()
         # FIXME(#3582): use https.
-        nightly_url = "http://static.rust-lang.org/cargo-dist/2014-10-02/%s" % tgz_file
+        nightly_url = "http://static.rust-lang.org/cargo-dist/2014-10-21/%s" % tgz_file
 
         download("Cargo nightly", nightly_url, tgz_file)
 

python/servo/build_commands.py

@@ -31,11 +31,15 @@ class MachCommands(CommandBase):
                      default=None,
                      action='store_true',
                      help='Build for Android')
+    @CommandArgument('--debug-mozjs',
+                     default=None,
+                     action='store_true',
+                     help='Enable debug assertions in mozjs')
     @CommandArgument('--verbose', '-v',
                      action='store_true',
                      help='Print verbose output')
     def build(self, target=None, release=False, jobs=None, android=None,
-              verbose=False):
+              verbose=False, debug_mozjs=False):
         self.ensure_bootstrapped()
 
         if android is None:
@@ -51,6 +55,13 @@ class MachCommands(CommandBase):
         if verbose:
             opts += ["-v"]
 
+        features = []
+        if debug_mozjs:
+            features += ["script/debugmozjs"]
+
+        if features:
+            opts += ["--features", "%s" % ' '.join(features)]
+
         build_start = time()
         if android:
             make_opts = []