[RLlib] Fix setup-dev.py error when creating a softlink for new_dashboard. (#12442)

python/ray/setup-dev.py

@@ -10,18 +10,25 @@ import subprocess
 import ray
 
 
-def do_link(package, force=False, local_path=""):
+def do_link(package, force=False, local_path=None):
     package_home = os.path.abspath(os.path.join(ray.__file__, f"../{package}"))
-    local_home = os.path.abspath(
-        os.path.join(__file__, local_path + f"../{package}"))
+    # Infer local_path automatically.
+    if local_path is None:
+        local_path = f"../{package}"
+    local_home = os.path.abspath(os.path.join(__file__, local_path))
+    # If installed package dir does not exist, continue either way. We'll
+    # remove it/create a link from there anyways.
     if not os.path.isdir(package_home):
         print(f"{package_home} does not exist. Continuing to link.")
-    assert os.path.isdir(local_home), local_home
+    # Make sure the path we are linking to does exist.
+    assert os.path.exists(local_home), local_home
+    # Confirm with user.
     if not force and not click.confirm(
             f"This will replace:\n  {package_home}\nwith "
             f"a symlink to:\n  {local_home}",
             default=True):
         return
+
     # Windows: Create directory junction.
     if os.name == "nt":
         try:
@@ -51,7 +58,7 @@ if __name__ == "__main__":
         "--yes", "-y", action="store_true", help="Don't ask for confirmation.")
     args = parser.parse_args()
 
-    do_link("rllib", force=args.yes, local_path="../../")
+    do_link("rllib", force=args.yes, local_path="../../../rllib")
     do_link("tune", force=args.yes)
     do_link("autoscaler", force=args.yes)
     do_link("scripts", force=args.yes)
@@ -59,8 +66,10 @@ if __name__ == "__main__":
     do_link("tests", force=args.yes)
     do_link("experimental", force=args.yes)
     do_link("util", force=args.yes)
-    do_link("dashboard", force=args.yes)
-    do_link("new_dashboard", force=args.yes)
+    # Link package's `new_dashboard` directly to local (repo's) dashboard.
+    # The repo's `new_dashboard` is a file, soft-linking to which will not work
+    # on Mac.
+    do_link("new_dashboard", force=args.yes, local_path="../../../dashboard")
     print("Created links.\n\nIf you run into issues initializing Ray, please "
           "ensure that your local repo and the installed Ray are in sync "
           "(pip install -U the latest wheels at "