rust_tools: remove llvm_tools.git usage

Looks like _nearly_ all of this can be replaced by existing bits in
`git_utils`.

This also has us call `repo init --head` instead of `repo init`. The
former works on `chromiumos-overlay`'s HEAD, rather than resetting it to
`cros/main`.

BUG=b:332713739
TEST=Unittests

Change-Id: I4cdcb3e9b0aea2e098445dd2ce81595235ea61b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/5522854
Commit-Queue: George Burgess <gbiv@chromium.org>
Reviewed-by: Bob Haarman <inglorion@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>

3 files changed, 59 insertions, 21 deletions

diff --git a/cros_utils/git_utils.py b/cros_utils/git_utils.py
index 33d52140..f02bc907 100644
--- a/cros_utils/git_utils.py
+++ b/cros_utils/git_utils.py
@@ -46,6 +46,20 @@ def is_full_git_sha(s: str) -> bool:
     return len(s) == 40 and all(x.isdigit() or "a" <= x <= "f" for x in s)
 
 
+def create_branch(git_repo: Path, branch_name: str) -> None:
+    """Creates a branch in the given repo.
+
+    Args:
+        git_repo: The path to the repo.
+        branch_name: The name of the branch to create.
+    """
+    subprocess.run(
+        ["repo", "start", branch_name, "--head"],
+        check=True,
+        cwd=git_repo,
+    )
+
+
 def upload_to_gerrit(
     git_repo: Path,
     remote: str,
diff --git a/rust_tools/rust_uprev.py b/rust_tools/rust_uprev.py
index 43c66324..a87025a1 100644
--- a/rust_tools/rust_uprev.py
+++ b/rust_tools/rust_uprev.py
@@ -35,6 +35,7 @@ import re
 import shlex
 import shutil
 import subprocess
+import textwrap
 import threading
 import time
 from typing import (
@@ -52,8 +53,8 @@ from typing import (
 )
 import urllib.request
 
+from cros_utils import git_utils
 from llvm_tools import chroot
-from llvm_tools import git
 
 
 T = TypeVar("T")
@@ -991,7 +992,7 @@ def rust_bootstrap_path() -> Path:
     return EBUILD_PREFIX.joinpath("dev-lang/rust-bootstrap")
 
 
-def create_new_repo(rust_version: RustVersion) -> None:
+def create_rust_uprev_branch(rust_version: RustVersion) -> None:
     output = get_command_output(
         ["git", "status", "--porcelain"], cwd=EBUILD_PREFIX
     )
@@ -1000,7 +1001,9 @@ def create_new_repo(rust_version: RustVersion) -> None:
             f"{EBUILD_PREFIX} has uncommitted changes, please either discard "
             "them or commit them."
         )
-    git.CreateBranch(EBUILD_PREFIX, f"rust-to-{rust_version}")
+    git_utils.create_branch(
+        EBUILD_PREFIX, branch_name=f"rust-to-{rust_version}"
+    )
 
 
 def build_cross_compiler(template_version: RustVersion) -> None:
@@ -1034,16 +1037,25 @@ def build_cross_compiler(template_version: RustVersion) -> None:
 
 def create_new_commit(rust_version: RustVersion) -> None:
     subprocess.check_call(["git", "add", "-A"], cwd=EBUILD_PREFIX)
-    messages = [
-        f"[DO NOT SUBMIT] dev-lang/rust: upgrade to Rust {rust_version}",
-        "",
-        "This CL is created by rust_uprev tool automatically." "",
-        "BUG=None",
-        "TEST=Use CQ to test the new Rust version",
-    ]
-    branch = f"rust-to-{rust_version}"
-    git.CommitChanges(EBUILD_PREFIX, messages)
-    git.UploadChanges(EBUILD_PREFIX, branch)
+    sha = git_utils.commit_all_changes(
+        EBUILD_PREFIX,
+        message=textwrap.dedent(
+            f"""\
+            [DO NOT SUBMIT] dev-lang/rust: upgrade to Rust {rust_version}
+
+            This CL is created by rust_uprev tool automatically.
+
+            BUG=None
+            TEST=Use CQ to test the new Rust version
+            """
+        ),
+    )
+    git_utils.upload_to_gerrit(
+        EBUILD_PREFIX,
+        remote=git_utils.CROS_EXTERNAL_REMOTE,
+        branch=git_utils.CROS_MAIN_BRANCH,
+        ref=sha,
+    )
 
 
 def run_in_chroot(cmd: Command, *args, **kwargs) -> subprocess.CompletedProcess:
@@ -1174,7 +1186,10 @@ def main() -> None:
             rust_ebuild = find_ebuild_for_package("dev-lang/rust")
             template_version = RustVersion.parse_from_ebuild(rust_ebuild)
 
-        run_step("create new repo", lambda: create_new_repo(args.uprev))
+        run_step(
+            "create rust upgrade branch",
+            lambda: create_rust_uprev_branch(args.uprev),
+        )
         if not args.skip_cross_compiler:
             run_step(
                 "build cross compiler",
diff --git a/rust_tools/rust_uprev_test.py b/rust_tools/rust_uprev_test.py
index e7942cad..730f07d8 100644
--- a/rust_tools/rust_uprev_test.py
+++ b/rust_tools/rust_uprev_test.py
@@ -1,4 +1,3 @@
-#!/usr/bin/env python3
 # Copyright 2020 The ChromiumOS Authors
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
@@ -13,7 +12,7 @@ import tempfile
 import unittest
 from unittest import mock
 
-from llvm_tools import git
+from cros_utils import git_utils
 
 
 # rust_uprev sets SOURCE_ROOT to the output of `repo --show-toplevel`.
@@ -748,14 +747,24 @@ class RustUprevOtherStagesTests(unittest.TestCase):
         )
 
     @mock.patch.object(rust_uprev, "get_command_output")
-    @mock.patch.object(git, "CreateBranch")
-    def test_create_new_repo(self, mock_branch, mock_output):
+    @mock.patch.object(git_utils, "create_branch")
+    def test_create_rust_upgrade_branch(self, mock_create_branch, mock_output):
         mock_output.return_value = ""
-        rust_uprev.create_new_repo(self.new_version)
-        mock_branch.assert_called_once_with(
-            rust_uprev.EBUILD_PREFIX, f"rust-to-{self.new_version}"
+        rust_uprev.create_rust_uprev_branch(self.new_version)
+        mock_create_branch.assert_called_once_with(
+            rust_uprev.EBUILD_PREFIX, branch_name=f"rust-to-{self.new_version}"
         )
 
+    @mock.patch.object(rust_uprev, "get_command_output")
+    @mock.patch.object(git_utils, "create_branch")
+    def test_create_rust_upgrade_branch_raises_if_unclean(
+        self, mock_create_branch, mock_output
+    ):
+        mock_output.return_value = "some file has modifications"
+        with self.assertRaisesRegex(RuntimeError, ".*uncommitted changes.*"):
+            rust_uprev.create_rust_uprev_branch(self.new_version)
+        mock_create_branch.assert_not_called()
+
     @mock.patch.object(rust_uprev, "run_in_chroot")
     def test_build_cross_compiler(self, mock_run_in_chroot):
         cros_targets = [