pre-upload: switch black (Python) format checks to chromite

The underlying tools are the same, so there shouldn't be any changes,
but this helps unify the logic a bit so improvements to `cros format`
automatically improve pre-upload.

BUG=None
TEST=CQ passes

Change-Id: Id45222de7c711bc6d99b297a9d53107f16d69c3c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/repohooks/+/4189457
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Sergey Frolov <sfrolov@google.com>

pre-upload.py

diff --git a/pre-upload.py b/pre-upload.py
index 6f7d19c..e5cbc7a 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -2378,51 +2378,18 @@
         _get_affected_files(commit, relative=True), included, excluded
     )
 
-    # Detect if the repo has their own black config.  If not, we want to
-    # use the one here.
-    config_path = REPOHOOKS_DIR / "pyproject.toml"
-    their_config = None
-    if project.dir:
-        their_config = Path(project.dir) / "pyproject.toml"
-        if their_config.is_file() and "tool.black" in their_config.read_text():
-            config_path = their_config
-
-    black_tool = Path(constants.DEPOT_TOOLS_DIR) / "black"
-    files_need_formatting = []
+    errors = []
+    project_path = Path(project.dir)
     for file in files:
         contents = _get_file_content(file, commit)
-        result = cros_build_lib.run(
-            [
-                black_tool,
-                f"--config={config_path}",
-                "--quiet",
-                "--check",
-                "--diff",
-                f"--stdin-filename={file}",
-                "-",
-            ],
-            print_cmd=False,
-            input=contents,
-            check=False,
-            stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
-            encoding="utf-8",
-        )
-        if result.returncode:
-            files_need_formatting.append((file, result.stdout))
+        if contents != formatters.python.Data(
+            contents, path=project_path / file
+        ):
+            errors.append(file)
 
-    if files_need_formatting:
-        black_cmd = [black_tool]
-        if config_path != their_config:
-            black_cmd.extend(["--config", config_path])
-        for file, _ in files_need_formatting:
-            black_cmd.append(file)
-        black_cmd_repr = cros_build_lib.CmdToStr(black_cmd)
+    if errors:
         return HookFailure(
-            f"Files need formatted with black.\n"
-            f"Run this command to fix automatically:\n"
-            f"  {black_cmd_repr}",
-            [f"{file}\n{diff}" for file, diff in files_need_formatting],
+            "Files not formatted (run `cros format` to fix):", errors
         )
 
     return None

pre-upload_unittest.py

diff --git a/pre-upload_unittest.py b/pre-upload_unittest.py
index 7dd082c..512b076 100755
--- a/pre-upload_unittest.py
+++ b/pre-upload_unittest.py
@@ -2866,17 +2866,7 @@
         )
         result = pre_upload._check_black(ProjectNamed("PROJECT"), "COMMIT")
         self.assertIsNotNone(result)
-        self.assertEqual(
-            f"Files need formatted with black.\n"
-            f"Run this command to fix automatically:\n"
-            f"  {constants.DEPOT_TOOLS_DIR}/black --config "
-            f"{pre_upload.REPOHOOKS_DIR}/pyproject.toml "
-            f"needs_reformatted.py",
-            result.msg,
-        )
-        self.assertEqual(
-            ["needs_reformatted.py"], [x.splitlines()[0] for x in result.items]
-        )
+        self.assertEqual(["needs_reformatted.py"], result.items)
 
     def testLocalConfig(self):
         """When a pyproject.toml exists in the project, it should be used."""
@@ -2888,13 +2878,8 @@
             "[tool.black]\n" "line-length = 6\n"
         )
         result = pre_upload._check_black(project, "COMMIT")
-        self.assertEqual(
-            f"Files need formatted with black.\n"
-            f"Run this command to fix automatically:\n"
-            f"  {constants.DEPOT_TOOLS_DIR}/black ok.py",
-            result.msg,
-        )
-        self.assertEqual(["ok.py"], [x.splitlines()[0] for x in result.items])
+        self.assertIsNotNone(result)
+        self.assertEqual(["ok.py"], result.items)
 
 
 class CheckRustfmtTest(PreUploadTestCase):