Improve build target argument handling

python/servo/build_commands.py

@@ -175,21 +175,23 @@ def build(self, target=None, release=False, dev=False, jobs=None,
             print("Please specify either --dev or --release.")
             sys.exit(1)
 
-        targets = []
+        if target and android:
+            print("Please specify either --target or --android.")
+            sys.exit(1)
+
         if release:
             opts += ["--release"]
-        if target:
-            opts += ["--target", target]
-            targets.append(target)
         if jobs is not None:
             opts += ["-j", jobs]
         if verbose:
             opts += ["-v"]
         if android:
-            opts += ["--target", self.config["android"]["target"]]
-            targets.append("arm-linux-androideabi")
+            target = self.config["android"]["target"]
+
+        if target:
+            opts += ["--target", target]
 
-        self.ensure_bootstrapped(targets=targets)
+        self.ensure_bootstrapped(target=target)
 
         if debug_mozjs or self.config["build"]["debug-mozjs"]:
             features += ["script/debugmozjs"]
@@ -330,8 +332,8 @@ def build_geckolib(self, jobs=None, verbose=False, release=False):
                      action='store_true',
                      help='Build in release mode')
     def build_gonk(self, jobs=None, verbose=False, release=False):
-        targets = ["arm-linux-androideabi"]
-        self.ensure_bootstrapped(targets=targets)
+        target = "arm-linux-androideabi"
+        self.ensure_bootstrapped(target=target)
 
         opts = []
         if jobs is not None:

python/servo/command_base.py

@@ -411,7 +411,7 @@ def android_support_dir(self):
     def android_build_dir(self, dev):
         return path.join(self.get_target_dir(), "arm-linux-androideabi", "debug" if dev else "release")
 
-    def ensure_bootstrapped(self, targets=[]):
+    def ensure_bootstrapped(self, target=None):
         if self.context.bootstrapped:
             return
 
@@ -422,13 +422,14 @@ def ensure_bootstrapped(self, targets=[]):
         rustc_binary_exists = path.exists(rustc_path)
 
         base_target_path = path.join(rust_root, "rustc", "lib", "rustlib")
-        target_paths = [path.join(base_target_path, t) for t in targets]
-        all_targets_exist = all([path.exists(p) for p in target_paths])
+        target_exists = True
+        if target is not None:
+            target_path = path.join(base_target_path, target)
+            target_exists = path.exists(target_path)
 
-        if (not self.config['tools']['system-rust'] and
-                (not rustc_binary_exists or not all_targets_exist)):
+        if not (self.config['tools']['system-rust'] or (rustc_binary_exists and target_exists)):
             print("looking for rustc at %s" % (rustc_path))
-            Registrar.dispatch("bootstrap-rust", context=self.context, target=targets)
+            Registrar.dispatch("bootstrap-rust", context=self.context, target=filter(None, [target]))
 
         cargo_path = path.join(self.config["tools"]["cargo-root"], "cargo", "bin",
                                "cargo" + BIN_SUFFIX)