Don't update working copy of the repository

Unless necessary (in the commit classifier script, where we are currently
"manually" applying patches from Phabricator).

Fixes #1469

bugbug/repository.py

@@ -1036,7 +1036,7 @@ def clean(hg, repo_dir, pull=True):
         logger.info(f"{repo_dir} pulled and updated")
 
 
-def clone(repo_dir, url="https://hg.mozilla.org/mozilla-central"):
+def clone(repo_dir, url="https://hg.mozilla.org/mozilla-central", update=False):
     try:
         with hglib.open(repo_dir) as hg:
             clean(hg, repo_dir)
@@ -1054,6 +1054,7 @@ def clone(repo_dir, url="https://hg.mozilla.org/mozilla-central"):
         sharebase=repo_dir + "-shared",
         networkattempts=7,
         branch=b"tip",
+        noupdate=not update,
     )
 
     cmd.insert(0, hglib.HGPATH)

scripts/commit_classifier.py

@@ -220,7 +220,7 @@ class CommitClassifier(object):
         )()
 
     def update_commit_db(self):
-        repository.clone(self.repo_dir)
+        repository.clone(self.repo_dir, update=True)
 
         assert db.download(repository.COMMITS_DB, support_files_too=True)
 

tests/test_repository.py

@@ -93,6 +93,10 @@ def test_clone(fake_hg_repo):
 
     repository.clone(tmp_repo_dir, url=remote)
 
+    # Assert that we don't have the file from the remote repository, since we cloned
+    # without updating the working dir.
+    assert not os.path.exists(os.path.join(tmp_repo_dir, "file1"))
+
     # Assert we have the commit from the remote repository.
     remote_revs = repository.get_revs(hg)
     with hglib.open(tmp_repo_dir) as tmp_hg:
@@ -115,6 +119,11 @@ def test_clone(fake_hg_repo):
     with hglib.open(tmp_repo_dir) as tmp_hg:
         assert repository.get_revs(tmp_hg) == remote_revs
 
+    repository.clone(f"{tmp_repo_dir}2", url=remote, update=True)
+    # Assert that we do have the file from the remote repository, since we cloned
+    # and updated the working dir.
+    assert os.path.exists(os.path.join(tmp_repo_dir, "file1"))
+
 
 def test_get_revs(fake_hg_repo):
     hg, local, remote = fake_hg_repo