getdeps: automatically detect if a build appears to be Facebook-internal

Summary:
Automatically detect the `--facebook-internal` flag based on the current
repository project name.

Reviewed By: wez

Differential Revision: D18621358

fbshipit-source-id: f2b3018169b151811eec455863a8bfc17667d4d8

build/fbcode_builder/getdeps.py

@@ -729,7 +729,13 @@ def parse_args():
         "--facebook-internal",
         help="Setup the build context as an FB internal build",
         action="store_true",
-        default=False,
+        default=None,
+    )
+    add_common_arg(
+        "--no-facebook-internal",
+        help="Perform a non-FB internal build, even when in an fbsource repository",
+        action="store_false",
+        dest="facebook_internal",
     )
 
     ap = argparse.ArgumentParser(

build/fbcode_builder/getdeps/buildopts.py

@@ -154,7 +154,7 @@ class BuildOptions(object):
     def is_linux(self):
         return self.host_type.is_linux()
 
-    def get_context_generator(self, host_tuple=None, facebook_internal=False):
+    def get_context_generator(self, host_tuple=None, facebook_internal=None):
         """ Create a manifest ContextGenerator for the specified target platform. """
         if host_tuple is None:
             host_type = self.host_type
@@ -163,6 +163,12 @@ class BuildOptions(object):
         else:
             host_type = HostType.from_tuple_string(host_tuple)
 
+        # facebook_internal is an Optional[bool]
+        # If it is None, default to assuming this is a Facebook-internal build if
+        # we are running in an fbsource repository.
+        if facebook_internal is None:
+            facebook_internal = self.fbsource_dir is not None
+
         return ContextGenerator(
             {
                 "os": host_type.ostype,