From 03af0cd664b3f079557e1efcdca6661f43269af2 Mon Sep 17 00:00:00 2001
From: Daniel Wagner-Hall <dwagnerhall@apple.com>
Date: Tue, 1 Feb 2022 13:57:55 -0500
Subject: [PATCH] Deduplicate input to ctx.expand_location

Works around https://github.com/bazelbuild/bazel/issues/14681
---
 rust/private/rustc.bzl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/rust/private/rustc.bzl b/rust/private/rustc.bzl
index 3e2f38e355..5cee1078dd 100644
--- a/rust/private/rustc.bzl
+++ b/rust/private/rustc.bzl
@@ -628,7 +628,12 @@ def construct_arguments(
     rustc_flags.add_all(rust_std_paths, before_each = "-L", format_each = "%s")
     rustc_flags.add_all(rust_flags)
 
-    data_paths = getattr(attr, "data", []) + getattr(attr, "compile_data", [])
+    # Deduplicate data paths due to https://github.com/bazelbuild/bazel/issues/14681
+    data_paths = getattr(attr, "data", [])[:]
+    for extra_data in getattr(attr, "compile_data", []):
+        if extra_data not in data_paths:
+            data_paths.append(extra_data)
+
     rustc_flags.add_all(
         expand_list_element_locations(
             ctx,