Added parse_args and check_impl_args functions to the migration module as well as some unittests.

Author: Rostepher

utils/build_swift/migration.py

@@ -12,16 +12,71 @@
 """
 
 
+import os
+import sys
+
 from swift_build_support.swift_build_support.targets import \
     StdlibDeploymentTarget
 
+from . import shell
+
 
 __all__ = [
+    'BUILD_SCRIPT_IMPL_PATH',
+    'parse_args',
+    'check_impl_args',
+
     'UnknownSDKError',
     'migrate_swift_sdks',
 ]
 
 
+BUILD_SCRIPT_IMPL_PATH = os.path.abspath(os.path.join(
+    os.path.dirname(__file__),
+    os.pardir,
+    'build-script-impl',
+))
+
+
+def parse_args(parser, argv=None):
+    """Parse arguments list with given argparse.ArgumentParser.argv
+
+    Returns a preprocessed list of arguments. Unknown arguments are stored on
+    the resulting namespace in the attribute `build_script_impl_args`. The
+    deprecated '--' argument separator is removed from the parsed argument
+    list.
+    """
+
+    if argv is None:
+        argv = sys.argv
+
+    # Remove the '--' separator, which is no longer needed
+    argv = [arg for arg in argv if arg != '--']
+
+    args, unknown_args = parser.parse_known_args(argv)
+    args.build_script_impl_args = unknown_args
+
+    return args
+
+
+def check_impl_args(args, command_executor=None):
+    """Verifies that args are kown `build-script-impl` arguments. Raises a
+    ValueError if an invalid argument is encountered.
+    """
+
+    sh = command_executor or shell.CommandExecutor()
+
+    command = [BUILD_SCRIPT_IMPL_PATH, '--check-args-only=1'] + args
+    pipe = sh.popen(command, stdin=shell.PIPE, stderr=shell.PIPE)
+    _, err = pipe.communicate()
+
+    if pipe.returncode != 0:
+        message = err.splitlines()[0].strip()
+        raise ValueError(message)
+
+
+# -----------------------------------------------------------------------------
+
 _SDK_TARGETS = {
     'OSX': StdlibDeploymentTarget.OSX.targets,
     'IOS': StdlibDeploymentTarget.iOS.targets,
@@ -33,8 +88,6 @@
 }
 
 
-# -----------------------------------------------------------------------------
-
 class UnknownSDKError(Exception):
     """Error indicating an unknown SDK was encountered when migrating to target
     triples.

utils/build_swift/tests/test_migration.py

@@ -9,6 +9,7 @@
 
 from .utils import TestCase
 from .. import migration
+from .. import shell
 
 
 def _get_sdk_targets(sdk_names):
@@ -25,7 +26,7 @@ def _get_sdk_target_names(sdk_names):
 
 # -----------------------------------------------------------------------------
 
-class TestMigrateSwiftSDKsMeta(type):
+class TestMigrationMeta(type):
     """Metaclass used to dynamically generate test methods.
     """
 
@@ -35,7 +36,7 @@ def __new__(cls, name, bases, attrs):
             test_name = 'test_migrate_swift_sdk_' + sdk_name
             attrs[test_name] = cls.generate_migrate_swift_sdks_test(sdk_name)
 
-        return super(TestMigrateSwiftSDKsMeta, cls).__new__(
+        return super(TestMigrationMeta, cls).__new__(
             cls, name, bases, attrs)
 
     @classmethod
@@ -52,11 +53,29 @@ def test(self):
         return test
 
 
-class TestMigrateSwiftSDKs(TestCase):
+class TestMigration(TestCase):
 
-    __metaclass__ = TestMigrateSwiftSDKsMeta
+    __metaclass__ = TestMigrationMeta
 
-    def test_multiple_swift_sdk_flags(self):
+    def test_parse_args(self):
+        pass
+
+    def test_check_impl_args_calls_build_script_impl(self):
+        sh = shell.NullExecutor()
+
+        migration.check_impl_args([], command_executor=sh)
+        self.assertListEqual(sh.history(), [
+            [migration.BUILD_SCRIPT_IMPL_PATH, '--check-args-only=1'],
+        ])
+
+    def test_check_impl_args_known_arg(self):
+        migration.check_impl_args(['--reconfigure'])
+
+    def test_check_impl_args_unknown_arg(self):
+        with self.assertRaises(ValueError):
+            migration.check_impl_args(['--unknown-arg'])
+
+    def test_migrate_multiple_swift_sdk_flags(self):
         args = [
             '--swift-sdks=OSX',
             '--swift-sdks=OSX;IOS;IOS_SIMULATOR'