llvm_tools: update_chromeos_llvm_hash no_delete_branch

This adds two flags to `update_chromeos_llvm_hash`:
- --no_delete_branch: Don't delete the branch when we're done.
- --no_upload_changes: Don't upload things to gerrit.

Then updates the users of git.py so that these changes don't
break anything.

BUG=None
TEST=run_tests_for.py llvm_tools/*
TEST=./update_chromeos_llvm_hash.py \
     --no_delete_branch \
     --no_upload_changes \
     --failure_mode=disable_patches \
     --llvm_version 498229

Change-Id: Ibce18f79ebfb1bf5de99175faf33225e68d5435b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/4867272
Commit-Queue: Jordan Abrahams-Whitehead <ajordanr@google.com>
Tested-by: Jordan Abrahams-Whitehead <ajordanr@google.com>
Reviewed-by: George Burgess <gbiv@chromium.org>

1 files changed, 19 insertions, 9 deletions

diff --git a/llvm_tools/git.py b/llvm_tools/git.py
index 3bb702c9..fc3d9b38 100755
--- a/llvm_tools/git.py
+++ b/llvm_tools/git.py
@@ -12,6 +12,7 @@ import os
 import re
 import subprocess
 import tempfile
+from typing import Iterable, Optional
 
 
 CommitContents = collections.namedtuple("CommitContents", ["url", "cl_number"])
@@ -73,15 +74,31 @@ def DeleteBranch(repo, branch):
     run_checked(["branch", "-q", "-D", branch])
 
 
+def CommitChanges(repo, commit_messages: Iterable[str]):
+    """Commit changes without uploading them."""
+    if not os.path.isdir(repo):
+        raise ValueError("Invalid path provided: %s" % repo)
+
+    # Create a git commit.
+    with tempfile.NamedTemporaryFile(mode="w+t", encoding="utf-8") as f:
+        f.write("\n".join(commit_messages))
+        f.flush()
+
+        subprocess.check_output(["git", "commit", "-F", f.name], cwd=repo)
+
+
 def UploadChanges(
-    repo, branch, commit_messages, reviewers=None, cc=None, wip=False
+    repo,
+    branch: str,
+    reviewers: Optional[Iterable[str]] = None,
+    cc: Optional[Iterable[str]] = None,
+    wip=False,
 ):
     """Uploads the changes in the specifed branch of the given repo for review.
 
     Args:
       repo: The absolute path to the repo where changes were made.
       branch: The name of the branch to upload.
-      commit_messages: A string of commit message(s) (i.e. '[message]'
       of the changes made.
       reviewers: A list of reviewers to add to the CL.
       cc: A list of contributors to CC about the CL.
@@ -98,13 +115,6 @@ def UploadChanges(
     if not os.path.isdir(repo):
         raise ValueError("Invalid path provided: %s" % repo)
 
-    # Create a git commit.
-    with tempfile.NamedTemporaryFile(mode="w+t") as f:
-        f.write("\n".join(commit_messages))
-        f.flush()
-
-        subprocess.check_output(["git", "commit", "-F", f.name], cwd=repo)
-
     # Upload the changes for review.
     git_args = [
         "repo",