Finding android specific files dynamically

ANDROID_SPECIFIC_FILES list is not accurate, requires manual
maintenance, and doesn't include generated files.

Test: TreeHugger
Change-Id: I85a8a886c88194a47e8d95a9fb1e401d17aaa75a

3 files changed, 19 insertions, 13 deletions

diff --git a/base_updater.py b/base_updater.py
index 0adc8f4..106f125 100644
--- a/base_updater.py
+++ b/base_updater.py
@@ -46,7 +46,7 @@ class Updater:
     def validate(self) -> str:
         """Checks whether aosp version is what it claims to be."""
         self.setup_remote()
-        return git_utils.diff(self._proj_path, self._old_identifier.version)
+        return git_utils.diff(self._proj_path, 'a', self._old_identifier.version)
 
     def check(self) -> None:
         """Checks whether a new version is available."""
diff --git a/git_utils.py b/git_utils.py
index 91be216..cddd78f 100644
--- a/git_utils.py
+++ b/git_utils.py
@@ -21,12 +21,6 @@ from pathlib import Path
 import hashtags
 import reviewers
 
-ANDROID_SPECIFIC_FILES = ["*Android.bp", "Android.mk", "CleanSpec.mk", "LICENSE",
-                          "NOTICE", "METADATA", "TEST_MAPPING", ".git",
-                          ".gitignore", "patches", "post_update.sh", "OWNERS",
-                          "README.android", "cargo2android*", "MODULE_LICENSE_*",
-                          "rules.mk", "cargo2rulesmk*", "cargo_embargo*"]
-
 UNWANTED_TAGS = ["*alpha*", "*Alpha*", "*beta*", "*Beta*", "*rc*", "*RC*", "*test*"]
 
 
@@ -255,6 +249,7 @@ def is_valid_url(proj_path: Path, url: str) -> bool:
                           stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
                           start_new_session=True).returncode == 0
 
+
 def list_remote_tags(proj_path: Path, remote_name: str) -> list[str]:
     """Lists tags in a remote repository."""
     cmd = ['git', "ls-remote", "--tags", remote_name]
@@ -264,13 +259,9 @@ def list_remote_tags(proj_path: Path, remote_name: str) -> list[str]:
     return lines
 
 
-def diff(proj_path: Path, sha_or_tag: str) -> str:
-    files = []
-    for file in ANDROID_SPECIFIC_FILES:
-        file = ":!" + file
-        files.append(file)
+def diff(proj_path: Path, diff_filter: str, revision: str) -> str:
     try:
-        cmd = ['git', 'diff', sha_or_tag, '--stat', '--'] + files
+        cmd = ['git', 'diff', revision, '--stat', f'--diff-filter={diff_filter}']
         out = subprocess.run(cmd, capture_output=True, cwd=proj_path,
                              check=True, text=True).stdout
         return out
diff --git a/tests/test_git_utils.py b/tests/test_git_utils.py
index 853145c..3c24302 100644
--- a/tests/test_git_utils.py
+++ b/tests/test_git_utils.py
@@ -119,5 +119,20 @@ class GetMostRecentTagTest(GitRepoTestCase):
         self.assertIsNone(git_utils.get_most_recent_tag(self.repo.path, "main"))
 
 
+class DiffTest(GitRepoTestCase):
+    """Tests for git_utils.diff."""
+    def test_git_diff_added_filter(self) -> None:
+        self.repo.init("main")
+        self.repo.commit(
+            "Add README.md", update_files={"README.md": "Hello, world!"}
+        )
+        first_commit = self.repo.head()
+        self.repo.commit(
+            "Add OWNERS", update_files={"OWNERS": "nobody"}
+        )
+        diff = git_utils.diff(self.repo.path, 'A', first_commit)
+        self.assertIn('OWNERS', diff)
+
+
 if __name__ == "__main__":
     unittest.main(verbosity=2)