From a62099ff24f5158d874195cb0cefde13db362ea5 Mon Sep 17 00:00:00 2001
From: Andrew Gu <andgu@fb.com>
Date: Mon, 20 Nov 2023 09:29:18 -0800
Subject: [PATCH] [DTensor] Replaced neg dim normalization with assert in
 global info

[ghstack-poisoned]
---
 torch/distributed/_tensor/_utils.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/torch/distributed/_tensor/_utils.py b/torch/distributed/_tensor/_utils.py
index 10d9b11c51b15..04b714c7789a3 100644
--- a/torch/distributed/_tensor/_utils.py
+++ b/torch/distributed/_tensor/_utils.py
@@ -145,8 +145,10 @@ def compute_global_tensor_info(
         if placement.is_shard():
             shard_placement = cast(Shard, placement)
             if shard_placement.dim < 0:
-                # normalize shard dim to be positive
-                shard_placement.dim += len(tensor_shape)
+                raise AssertionError(
+                    "Shard placements should have negative dims normalized in "
+                    f"the user-facing APIs: {shard_placement}"
+                )
             shard_dim = shard_placement.dim
 
             assert (