Add per-project use-shipit flag

Summary:
X-link: facebookincubator/zstrong#853

For projects that can't use the simple shipit transformer (e.g. hsthrift) and projects where it would be a pain to duplicate the shipit config (e.g. Glean).

Reviewed By: pepeiborra

Differential Revision: D58055453

fbshipit-source-id: f693a320f42cfccd9808306b4ad8b1f31ce00f97

build/fbcode_builder/getdeps/manifest.py

@@ -45,6 +45,7 @@
             "fbsource_path": OPTIONAL,
             "shipit_project": OPTIONAL,
             "shipit_fbcode_builder": OPTIONAL,
+            "use_shipit": OPTIONAL,
         },
     },
     "dependencies": {"optional_section": True, "allow_values": False},
@@ -396,8 +397,9 @@ def get_repo_url(self, ctx):
         return self.get("git", "repo_url", ctx=ctx)
 
     def create_fetcher(self, build_options, ctx):
-        use_real_shipit = (
-            ShipitTransformerFetcher.available() and build_options.use_shipit
+        use_real_shipit = ShipitTransformerFetcher.available() and (
+            build_options.use_shipit
+            or self.get("manifest", "use_shipit", defval="false", ctx=ctx) == "true"
         )
         if (
             not use_real_shipit