Reland "Add _CheckAndroidNullAwayAnnotatedClasses PRESUBMIT check"

Doing a simpler check, not trying to figure out if the annotation is in the class declaration or on a method declaration. It would be
very rare for a method to be annotation and not the class.

This reverts commit ae8498e751.

Reason for revert: Fixed version

Original change's description:
> Revert "Add _CheckAndroidNullAwayAnnotatedClasses PRESUBMIT check"
>
> This reverts commit cfe861e365.
>
> Reason for revert: Doesn't ignore comments
>
> Original change's description:
> > Add _CheckAndroidNullAwayAnnotatedClasses PRESUBMIT check
> >
> > Warn when a .java file is missing @NullMarked and @NullUnmarked.
> >
> > Temporarily disabled in //android_webview and //chrome while migrating.
> >
> > Bug: 404884589
> > Change-Id: I38e331bcec6f3a3f2147c0999fd4dca8fef145d5
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6373892
> > Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
> > Reviewed-by: Andrew Grieve <agrieve@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#1435461}
>
> Bug: 404884589
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Change-Id: I669658f3f21cab9365f0c50b4e0191a1e6a608a0
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6377728
> Auto-Submit: Henrique Nakashima <hnakashima@chromium.org>
> Commit-Queue: Andrew Grieve <agrieve@chromium.org>
> Reviewed-by: Andrew Grieve <agrieve@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1435593}

Bug: 404884589
Change-Id: I11d0ed28bf1941e72df5dcc457fb9d7e62dc89ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6381838
Auto-Submit: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1436182}

PRESUBMIT.py

@@ -5957,6 +5957,7 @@ def ChecksAndroidSpecificOnUpload(input_api, output_api):
     results.extend(_CheckNewImagesWarning(input_api, output_api))
     results.extend(_CheckAndroidNoBannedImports(input_api, output_api))
     results.extend(_CheckAndroidInfoBarDeprecation(input_api, output_api))
+    results.extend(_CheckAndroidNullAwayAnnotatedClasses(input_api, output_api))
     return results
 
 
@@ -7578,6 +7579,48 @@ a subclass of it), or use "@Rule BaseRobolectricTestRule".
     return results
 
 
+def _CheckAndroidNullAwayAnnotatedClasses(input_api, output_api):
+    """Checks that Java classes/interfaces/annotations are null-annotated."""
+
+    nullmarked_annotation = input_api.re.compile(r'^\s*@(NullMarked|NullUnmarked)')
+
+    missing_annotation_errors = []
+
+    def _FilterFile(affected_file):
+        return input_api.FilterSourceFile(
+            affected_file,
+        files_to_skip=(_EXCLUDED_PATHS + _TEST_CODE_EXCLUDED_PATHS + input_api.
+                       DEFAULT_FILES_TO_SKIP + (
+                           r'.*Test.*\.java',
+                           r'^android_webview/.*', # Temporary, crbug.com/389129271
+                           r'^build/.*',
+                           r'^chrome/.*', # Temporary, crbug.com/389129271
+                           r'^chromecast/.*',
+                           r'^components/cronet/.*',
+                           r'^tools/.*',
+                       )),
+        files_to_check=[r'.*\.java$'])
+
+    for f in input_api.AffectedSourceFiles(_FilterFile):
+        for line in f.NewContents():
+            if nullmarked_annotation.search(line):
+                break
+        else:
+            missing_annotation_errors.append(str(f.LocalPath()))
+
+    results = []
+
+    if missing_annotation_errors:
+        results.append(
+            output_api.PresubmitPromptWarning(
+                """
+Please add @NullMarked and fix the NullAway warnings in the following files
+(see https://chromium.googlesource.com/chromium/src/+/main/styleguide/java/nullaway.md):
+""", missing_annotation_errors))
+
+    return results
+
+
 def CheckNoJsInIos(input_api, output_api):
     """Checks to make sure that JavaScript files are not used on iOS."""
 

PRESUBMIT_test.py

@@ -5138,6 +5138,84 @@ class CheckAndroidTestAnnotations(unittest.TestCase):
         self.assertIn('OneTest.java', errors[0].items[0])
 
 
+class CheckAndroidNullAwayAnnotatedClasses(unittest.TestCase):
+    """Test the _CheckAndroidNullAwayAnnotatedClasses presubmit check."""
+
+    def testDetectsInClasses(self):
+        """Tests that missing @NullMarked or @NullUnmarked are correctly flagged in classes."""
+        mock_input = MockInputApi()
+        mock_input.files = [
+            MockFile('path/OneMissing.java', ['public class OneMissing']),
+            MockFile('path/TwoMarked.java', [
+                '@NullMarked',
+                'public class TwoMarked {',
+            ]),
+            MockFile('path/ThreeMarked.java', [
+                '@NullUnmarked',
+                'public class ThreeMarked {',
+            ]),
+            MockFile('path/FourMissing.java', ['class FourMissing']),
+        ]
+        results = PRESUBMIT._CheckAndroidNullAwayAnnotatedClasses(mock_input, MockOutputApi())
+        self.assertEqual(1, len(results))
+        self.assertEqual('warning', results[0].type)
+        self.assertEqual(2, len(results[0].items))
+        self.assertIn('OneMissing.java', results[0].items[0])
+        self.assertIn('FourMissing.java', results[0].items[1])
+
+    def testDetectsInAnnotations(self):
+        """Tests that missing @NullMarked or @NullUnmarked are correctly flagged in annotations."""
+        mock_input = MockInputApi()
+        mock_input.files = [
+            MockFile('path/OneMissing.java', ['@interface OneMissing']),
+            MockFile('path/TwoMarked.java', [
+                '@NullMarked',
+                '@interface TwoMarked {',
+            ]),
+        ]
+        results = PRESUBMIT._CheckAndroidNullAwayAnnotatedClasses(mock_input, MockOutputApi())
+        self.assertEqual(1, len(results))
+        self.assertEqual('warning', results[0].type)
+        self.assertEqual(1, len(results[0].items))
+        self.assertIn('OneMissing.java', results[0].items[0])
+
+    def testDetectsInInterfaces(self):
+        """Tests that missing @NullMarked or @NullUnmarked are correctly flagged in interfaces."""
+        mock_input = MockInputApi()
+        mock_input.files = [
+            MockFile('path/OneMissing.java', ['interface OneMissing']),
+            MockFile('path/TwoMarked.java', [
+                '@NullMarked',
+                'interface TwoMarked {',
+            ]),
+        ]
+        results = PRESUBMIT._CheckAndroidNullAwayAnnotatedClasses(mock_input, MockOutputApi())
+        self.assertEqual(1, len(results))
+        self.assertEqual('warning', results[0].type)
+        self.assertEqual(1, len(results[0].items))
+        self.assertIn('OneMissing.java', results[0].items[0])
+
+    def testExcludesTests(self):
+        """Tests that missing @NullMarked or @NullUnmarked are not flagged in tests."""
+        mock_input = MockInputApi()
+        mock_input.files = [
+            MockFile('path/OneTest.java', ['public class OneTest']),
+        ]
+        results = PRESUBMIT._CheckAndroidNullAwayAnnotatedClasses(mock_input, MockOutputApi())
+        self.assertEqual(0, len(results))
+
+    def testExcludesTestSupport(self):
+        """Tests that missing @NullMarked or @NullUnmarked are not flagged in test support classes."""
+        mock_input = MockInputApi()
+        mock_input.files = [
+            MockFile('path/test/Two.java', [
+                'public class Two'
+            ]),
+        ]
+        results = PRESUBMIT._CheckAndroidNullAwayAnnotatedClasses(mock_input, MockOutputApi())
+        self.assertEqual(0, len(results))
+
+
 class AssertNoJsInIosTest(unittest.TestCase):
     def testErrorJs(self):
         input_api = MockInputApi()