feat(lifecycle): add deprecated snap command

snapcraft/application.py

@@ -34,6 +34,7 @@
 from craft_providers import bases
 from overrides import override
 
+import snapcraft.commands
 from snapcraft import cli, errors, models, services
 from snapcraft.commands import unimplemented
 from snapcraft.models import Architecture
@@ -253,6 +254,7 @@ def main() -> int:
             craft_app_commands.lifecycle.StageCommand,
             craft_app_commands.lifecycle.PrimeCommand,
             craft_app_commands.lifecycle.PackCommand,
+            snapcraft.commands.lifecycle.SnapCommand,
             unimplemented.RemoteBuild,
             unimplemented.Snap,  # Hidden (legacy compatibility)
             unimplemented.Plugins,

snapcraft/commands/__init__.py

@@ -17,8 +17,10 @@
 """Snapcraft commands."""
 
 from . import core22, legacy
+from .lifecycle import SnapCommand
 
 __all__ = [
     "core22",
     "legacy",
+    "SnapCommand",
 ]

snapcraft/commands/lifecycle.py

@@ -0,0 +1,48 @@
+# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
+#
+# Copyright 2024 Canonical Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Snapcraft lifecycle commands."""
+
+import argparse
+from typing import Any
+
+import craft_application.commands
+from craft_cli import emit
+from typing_extensions import override
+
+# pylint: disable=too-many-ancestors
+
+
+class SnapCommand(craft_application.commands.lifecycle.PackCommand):
+    """Deprecated legacy command to pack the final snap payload."""
+
+    name = "snap"
+    hidden = True
+
+    @override
+    def _run(
+        self,
+        parsed_args: argparse.Namespace,
+        step_name: str | None = None,
+        **kwargs: Any,
+    ) -> None:
+        emit.progress(
+            "Warning: the 'snap' command is deprecated and will be removed "
+            "in a future release of Snapcraft. Please use 'pack' instead.",
+            permanent=True,
+        )
+
+        super()._run(parsed_args, step_name, **kwargs)

tests/unit/commands/test_lifecycle.py

@@ -20,6 +20,8 @@
 import pytest
 
 import snapcraft.commands.core22.lifecycle as core22_lifecycle
+from snapcraft.application import APP_METADATA
+from snapcraft.commands import lifecycle
 
 
 @pytest.mark.parametrize(
@@ -88,3 +90,17 @@ def test_core22_pack_command_with_directory(mocker):
     cmd.run(argparse.Namespace(directory=".", output=None, compression=None))
     assert lifecycle_run_mock.mock_calls == []
     assert pack_mock.mock_calls[0] == call(".", output=None)
+
+
+def test_snap_command_fallback(tmp_path, emitter, mocker, fake_services):
+    """Test that the snap command is falling back to the pack command."""
+    parsed_args = argparse.Namespace(parts=[], output=tmp_path)
+    mock_pack = mocker.patch("craft_application.commands.lifecycle.PackCommand._run")
+    cmd = lifecycle.SnapCommand({"app": APP_METADATA, "services": fake_services})
+    cmd.run(parsed_args=parsed_args)
+    mock_pack.assert_called_once()
+    emitter.assert_progress(
+        "Warning: the 'snap' command is deprecated and will be removed "
+        "in a future release of Snapcraft. Please use 'pack' instead.",
+        permanent=True,
+    )