In WPT importer, abort if there are exportable-but-not-yet-exported commits.

third_party/WebKit/Tools/Scripts/webkitpy/w3c/common.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Utility functions used both when importing and exporting."""
 
 import logging
 
 from webkitpy.w3c.chromium_commit import ChromiumCommit
 
 
 WPT_DEST_NAME = 'wpt'
 CSS_DEST_NAME = 'csswg-test'
 
 # TODO(qyearsley): This directory should be able to be constructed with
 # WebKitFinder and WPT_DEST_NAME, plus the string "external".
 CHROMIUM_WPT_DIR = 'third_party/WebKit/LayoutTests/external/wpt/'
 
 # Our mirrors of the official w3c repos, which we pull from.
 WPT_REPO_URL = 'https://chromium.googlesource.com/external/w3c/web-platform-tests.git'
 CSS_REPO_URL = 'https://chromium.googlesource.com/external/w3c/csswg-test.git'
 
 _log = logging.getLogger(__name__)
 
 
-def exportable_commits_since(commit, host, local_wpt):
+def exportable_commits_since(chromium_commit_hash, host, local_wpt):
     """Lists exportable commits after a certain point.
 
     Args:
-        commit: The SHA of the Chromium commit from which this method will look.
+        chromium_commit_hash: The SHA of the Chromium commit from which this
+            method will look. This commit is not included in the commits searched.
         host: A Host object.
         local_wpt: A LocalWPT instance, used to see whether a Chromium commit
             can be applied cleanly in the upstream repo.
 
     Returns:
-        A list of ChromiumCommit objects for commits that are exportable since
+        A list of ChromiumCommit objects for commits that are exportable after
         the given commit, in chronological order.
     """
     chromium_repo_root = host.executive.run_command(['git', 'rev-parse', '--show-toplevel']).strip()
 
     wpt_path = chromium_repo_root + '/' + CHROMIUM_WPT_DIR
-    commit_hashes = host.executive.run_command(
-        ['git', 'rev-list', '{}..HEAD'.format(commit), '--reverse', '--', wpt_path]).splitlines()
-
+    commit_range = '{}..HEAD'.format(chromium_commit_hash)
+    commit_hashes = host.executive.run_command(['git', 'rev-list', commit_range, '--reverse', '--', wpt_path]).splitlines()
     chromium_commits = [ChromiumCommit(host, sha=sha) for sha in commit_hashes]
-    return [c for c in chromium_commits if is_exportable(c, local_wpt)]
+    return [commit for commit in chromium_commits if is_exportable(commit, local_wpt)]
 
 
 def is_exportable(chromium_commit, local_wpt):
     """Checks whether a given patch is exportable and can be applied."""
     patch = chromium_commit.format_patch()
     return (patch and
             local_wpt.test_patch(patch) and
             'NOEXPORT=true' not in chromium_commit.message() and
             not chromium_commit.message().startswith('Import '))