feat: support shallow git clones

src/taskgraph/run-task/run-task

@@ -600,6 +600,7 @@ def git_checkout(
     commit: Optional[str],
     ssh_key_file: Optional[Path],
     ssh_known_hosts_file: Optional[Path],
+    shallow: bool = False,
 ):
     env = {
         # abort if transfer speed is lower than 1kB/s for 1 minute
@@ -633,12 +634,17 @@ def git_checkout(
 
     if not os.path.exists(destination_path):
         # Repository doesn't already exist, needs to be cloned
+        repo_url = base_repo if base_repo else head_repo
         args = [
             "git",
             "clone",
-            base_repo if base_repo else head_repo,
+            repo_url,
             destination_path,
         ]
+
+        # Only add --depth=1 for non-local repositories
+        if shallow and not os.path.exists(repo_url):
+            args.append("--depth=1")
 
         retry_required_command(b"vcs", args, extra_env=env)
 
@@ -930,6 +936,7 @@ def collect_vcs_options(args, project, name):
         "repo-type": repo_type,
         "ssh-secret-name": private_key_secret,
         "pip-requirements": pip_requirements,
+        "shallow": args.shallow,
     }
 
 
@@ -978,6 +985,7 @@ def vcs_checkout_from_args(options):
                 revision,
                 ssh_key_file,
                 ssh_known_hosts_file,
+                options.get("shallow", False),
             )
         elif options["repo-type"] == "hg":
             if not revision and not ref:
@@ -1061,6 +1069,9 @@ def main(args):
     parser.add_argument("--user", default="worker", help="user to run as")
     parser.add_argument("--group", default="worker", help="group to run as")
     parser.add_argument("--task-cwd", help="directory to run the provided command in")
+    parser.add_argument("--shallow", action="store_true",
+        default=False, help="perform a shallow clone (default: false)",
+    )
 
     repositories = os.environ.get("REPOSITORIES")
     if repositories:

test/test_scripts_run_task.py

@@ -178,6 +178,7 @@ def test_collect_vcs_options(monkeypatch, run_task_mod, env, extra_expected):
     args = Namespace()
     setattr(args, f"{name}_checkout", checkout)
     setattr(args, f"{name}_sparse_profile", False)
+    setattr(args, "shallow", False)
 
     result = run_task_mod.collect_vcs_options(args, name, name)
 
@@ -197,6 +198,7 @@ def test_collect_vcs_options(monkeypatch, run_task_mod, env, extra_expected):
         "ssh-secret-name": env.get("SSH_SECRET_NAME"),
         "sparse-profile": False,
         "store-path": env.get("HG_STORE_PATH"),
+        "shallow": False,
     }
     if "PIP_REQUIREMENTS" in env:
         expected["pip-requirements"] = os.path.join(
@@ -354,13 +356,14 @@ def _commit_file(message, filename):
 
 
 @pytest.mark.parametrize(
-    "base_ref,ref,files,hash_key",
+    "base_ref,ref,files,hash_key,shallow",
     [
-        (None, None, ["mainfile"], "main"),
-        (None, "main", ["mainfile"], "main"),
-        (None, "mybranch", ["mainfile", "branchfile"], "branch"),
-        ("main", "main", ["mainfile"], "main"),
-        ("main", "mybranch", ["mainfile", "branchfile"], "branch"),
+        (None, None, ["mainfile"], "main", False),
+        (None, "main", ["mainfile"], "main", False),
+        (None, "mybranch", ["mainfile", "branchfile"], "branch", False),
+        ("main", "main", ["mainfile"], "main", False),
+        ("main", "mybranch", ["mainfile", "branchfile"], "branch", False),
+        ("main", "mybranch", ["mainfile", "branchfile"], "branch", True),
     ],
 )
 def test_git_checkout(
@@ -371,6 +374,7 @@ def test_git_checkout(
     ref,
     files,
     hash_key,
+    shallow,
 ):
     with tempfile.TemporaryDirectory() as workdir:
         destination = os.path.join(workdir, "destination")
@@ -384,6 +388,7 @@ def test_git_checkout(
             commit=None,
             ssh_key_file=None,
             ssh_known_hosts_file=None,
+            shallow=shallow,
         )
 
         # Check desired files exist
@@ -403,10 +408,12 @@ def test_git_checkout(
             assert current_rev == mock_git_repo[hash_key]
 
 
+@pytest.mark.parametrize("shallow", [True, False])
 def test_git_checkout_with_commit(
     mock_stdin,
     run_task_mod,
     mock_git_repo,
+    shallow,
 ):
     with tempfile.TemporaryDirectory() as workdir:
         destination = os.path.join(workdir, "destination")
@@ -420,6 +427,7 @@ def test_git_checkout_with_commit(
             commit=mock_git_repo["branch"],
             ssh_key_file=None,
             ssh_known_hosts_file=None,
+            shallow=shallow,
         )