Revert "dist: forbid multiple inputs which create same file"

This reverts commit 6a733b848a6b89884121f1eebb93d1ed7d2d474a.

Reason for revert: broke kernel_raviole_kleaf build on kernel-android-gs-pixel-mainline

Change-Id: Ia585d2b470e4ef0ba45bfef5df9297f0ecc422ac
diff --git a/dist/dist.bzl b/dist/dist.bzl
index bab387e..23b6596 100644
--- a/dist/dist.bzl
+++ b/dist/dist.bzl
@@ -66,7 +66,6 @@
         archive_prefix = None,
         dist_dir = None,
         wipe_dist_dir = None,
-        allow_duplicate_filenames = None,
         log = None,
         **kwargs):
     """A dist rule to copy files out of Bazel's output directory into a custom location.
@@ -104,14 +103,6 @@
           See details by running the target with `--help`.
         wipe_dist_dir: If true, and `dist_dir` already exists, `dist_dir` will be removed prior to
           copying.
-        allow_duplicate_filenames: If true, duplicate filenames from different sources will be allowed to
-          be copied to the same `dist_dir` (with subsequent sources overwriting previous sources).
-
-          With this option enabled, order matters. The final source of the file listed in `data` will be the
-          final version copied.
-
-          Use of this option is discouraged. Preferably, the input `data` targets would not include labels
-          which produce a duplicate filename. This option is available as a last resort.
         log: If specified, `--log <log>` is provided to the script by default. This sets the
           default log level of the script.
 
@@ -137,8 +128,6 @@
         default_args += ["--dist_dir", dist_dir]
     if wipe_dist_dir:
         default_args.append("--wipe_dist_dir")
-    if allow_duplicate_filenames:
-        default_args.append("--allow_duplicate_filenames")
     if log != None:
         default_args += ["--log", log]
 
diff --git a/dist/dist.py b/dist/dist.py
index c384664..580b686 100644
--- a/dist/dist.py
+++ b/dist/dist.py
@@ -32,7 +32,6 @@
 """
 
 import argparse
-import collections
 import glob
 import logging
 import os
@@ -40,21 +39,6 @@
 import sys
 import tarfile
 
-def ensure_unique_filenames(files):
-    basename_to_srcs_map = collections.defaultdict(list)
-    for f in files:
-        basename_to_srcs_map[os.path.basename(f)].append(f)
-
-    duplicates_exist = False
-    for (basename, srcs) in basename_to_srcs_map.items():
-        if len(srcs) > 1:
-            duplicates_exist = True
-            logging.error('Destination filename "%s" has multiple possible sources: %s',
-                         basename, srcs)
-
-    if duplicates_exist:
-        sys.exit(1)
-
 
 def files_to_dist(pattern):
     # Assume that dist.bzl is in the same package as dist.py
@@ -72,10 +56,7 @@
 
 
 def copy_files_to_dist_dir(files, archives, dist_dir, flat, prefix,
-    strip_components, archive_prefix, wipe_dist_dir, allow_duplicate_filenames, **ignored):
-
-    if flat and not allow_duplicate_filenames:
-        ensure_unique_filenames(files)
+    strip_components, archive_prefix, wipe_dist_dir, **ignored):
 
     if wipe_dist_dir and os.path.exists(dist_dir):
         shutil.rmtree(dist_dir)
@@ -158,11 +139,6 @@
         action="store_true",
         help="remove existing dist_dir prior to running"
     )
-    parser.add_argument(
-        "--allow_duplicate_filenames",
-        action="store_true",
-        help="allow multiple files with the same name to be copied to dist_dir (overwriting)"
-    )
 
     args = parser.parse_args(sys.argv[1:])