Rebase Ray on latest arrow (remove numbuf from Ray). (#910)

* remove some stuff

* put get roundtrip working

* fixes

* more fixes

* cleanup

* fix tests

* latest arrow

* fixes

* fix tests

* fix linting

* rebase

* fixes

* fix bug

* bring back libgcc error

* fix linting

* use official arrow repo

* fixes

python/ray/__init__.py

@@ -10,6 +10,36 @@ pyarrow_path = os.path.join(os.path.abspath(os.path.dirname(__file__)),
                             "pyarrow_files")
 sys.path.insert(0, pyarrow_path)
 
+# See https://github.com/ray-project/ray/issues/131.
+helpful_message = """
+
+If you are using Anaconda, try fixing this problem by running:
+
+    conda install libgcc
+"""
+
+try:
+    import pyarrow  # noqa: F401
+except ImportError as e:
+    if ((hasattr(e, "msg") and isinstance(e.msg, str) and
+            ("libstdc++" in e.msg or "CXX" in e.msg))):
+        # This code path should be taken with Python 3.
+        e.msg += helpful_message
+    elif (hasattr(e, "message") and isinstance(e.message, str) and
+          ("libstdc++" in e.message or "CXX" in e.message)):
+        # This code path should be taken with Python 2.
+        condition = (hasattr(e, "args") and isinstance(e.args, tuple) and
+                     len(e.args) == 1 and isinstance(e.args[0], str))
+        if condition:
+            e.args = (e.args[0] + helpful_message,)
+        else:
+            if not hasattr(e, "args"):
+                e.args = ()
+            elif not isinstance(e.args, tuple):
+                e.args = (e.args,)
+            e.args += (helpful_message,)
+    raise
+
 from ray.worker import (register_class, error_info, init, connect, disconnect,
                         get, put, wait, remote, log_event, log_span,
                         flush_log, get_gpu_ids)  # noqa: E402