Fix PRESUBMIT.py issue with manual presubmit invocations

I've been experimenting with using the Jj source control tool, and
since it's not natively supported by `depot_tools`, this means I have
to manually invoke `git cl presubmit`. `git cl presubmit` accepts a
single argument which is the name of the upstream branch.

The way this is intended to work is that the upstream branch name gets
passed into the `PRESUBMIT.py` scripts, and they use it rather than
making assumptions about what the upstream branch is.

Prior to this change, our presubmit scripts for _fe_analyzer_shared,
front_end, frontend_server, and kernel were ignoring the upstream
branch and instead using git's `@{u}` shorthand (see
https://git-scm.com/docs/git-rev-parse). This caused them to behave
strangely when no upstream branch is set, which sometimes happens when
running `git cl presubmit` manually.

This change avoids the strange behavior by getting the upstream branch
from the input to `PRESUBMIT.py`, as intended.

Change-Id: I6a6a696423221d7b945b083fd72585f1f5a7e312
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/447626
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Paul Berry <[email protected]>

Author: stereotype441

pkg/_fe_analyzer_shared/PRESUBMIT.py

@@ -48,7 +48,11 @@ def runSmokeTest(input_api, output_api):
         print('WARNING: CFE et al presubmit_helper not found: %s' % test_helper)
         return []
 
-    args = [dart, test_helper, input_api.PresubmitLocalPath()]
+    args = [
+        dart, test_helper,
+        input_api.PresubmitLocalPath(),
+        input_api.change.UpstreamBranch()
+    ]
     process = subprocess.Popen(args,
                                stdout=subprocess.PIPE,
                                stdin=subprocess.PIPE)

pkg/front_end/PRESUBMIT.py

@@ -48,7 +48,11 @@ def runSmokeTest(input_api, output_api):
         print('WARNING: CFE et al presubmit_helper not found: %s' % test_helper)
         return []
 
-    args = [dart, test_helper, input_api.PresubmitLocalPath()]
+    args = [
+        dart, test_helper,
+        input_api.PresubmitLocalPath(),
+        input_api.change.UpstreamBranch()
+    ]
     process = subprocess.Popen(args,
                                stdout=subprocess.PIPE,
                                stdin=subprocess.PIPE)

pkg/front_end/presubmit_helper.dart

@@ -13,10 +13,13 @@ import 'test/utils/io_utils.dart';
 Future<void> main(List<String> args) async {
   Directory.current = Directory.fromUri(_repoDir);
   Stopwatch stopwatch = new Stopwatch()..start();
-  // Expect something like /full/path/to/sdk/pkg/some_dir/whatever/else
-  if (args.length != 1) throw "Need exactly one argument.";
+  // Expect something like:
+  //   /full/path/to/sdk/pkg/some_dir/whatever/else upstreamBranch
+  if (args.length != 2) throw "Need exactly two arguments.";
 
-  final List<String> changedFiles = getChangedFiles(collectUncommitted: false);
+  String upstreamBranch = args[1];
+  final List<String> changedFiles = getChangedFiles(
+      collectUncommitted: false, upstreamBranch: upstreamBranch);
   String callerPath = args[0].replaceAll("\\", "/");
   if (!_shouldRun(changedFiles, callerPath)) {
     return;
@@ -291,7 +294,8 @@ Future<void> _executePendingWorkItems(List<Work> workItems) async {
 /// Queries git about changes against upstream, or origin/main if no upstream is
 /// set. This is similar (but different), I believe, to what
 /// `git cl presubmit` does.
-List<String> getChangedFiles({required bool collectUncommitted}) {
+List<String> getChangedFiles(
+    {required bool collectUncommitted, required String upstreamBranch}) {
   Set<String> paths = {};
   void collectChanges(ProcessResult processResult) {
     for (String line in processResult.stdout.toString().split("\n")) {
@@ -311,7 +315,7 @@ List<String> getChangedFiles({required bool collectUncommitted}) {
         "diff",
         "--name-status",
         "--no-renames",
-        "@{u}...HEAD",
+        "$upstreamBranch...HEAD",
       ],
       runInShell: true);
   if (result.exitCode != 0) {

pkg/front_end/tool/format_cl.dart

@@ -12,7 +12,7 @@ import '../test/utils/io_utils.dart';
 Future<void> main() async {
   Uri executable = getDartExecutable();
   final List<String> allChangedFiles =
-      getChangedFiles(collectUncommitted: true);
+      getChangedFiles(collectUncommitted: true, upstreamBranch: '@{u}');
   if (allChangedFiles.isEmpty) {
     print("No changes in CL.");
     return;

pkg/frontend_server/PRESUBMIT.py

@@ -48,7 +48,11 @@ def runSmokeTest(input_api, output_api):
         print('WARNING: CFE et al presubmit_helper not found: %s' % test_helper)
         return []
 
-    args = [dart, test_helper, input_api.PresubmitLocalPath()]
+    args = [
+        dart, test_helper,
+        input_api.PresubmitLocalPath(),
+        input_api.change.UpstreamBranch()
+    ]
     process = subprocess.Popen(args,
                                stdout=subprocess.PIPE,
                                stdin=subprocess.PIPE)

pkg/kernel/PRESUBMIT.py

@@ -48,7 +48,11 @@ def runSmokeTest(input_api, output_api):
         print('WARNING: CFE et al presubmit_helper not found: %s' % test_helper)
         return []
 
-    args = [dart, test_helper, input_api.PresubmitLocalPath()]
+    args = [
+        dart, test_helper,
+        input_api.PresubmitLocalPath(),
+        input_api.change.UpstreamBranch()
+    ]
     process = subprocess.Popen(args,
                                stdout=subprocess.PIPE,
                                stdin=subprocess.PIPE)