feat(craft-application): support root packages for core24

snapcraft/application.py

@@ -38,7 +38,10 @@
 from snapcraft.commands import unimplemented
 from snapcraft.extensions import apply_extensions
 from snapcraft.models import Architecture
-from snapcraft.models.project import validate_architectures
+from snapcraft.models.project import (
+    apply_root_packages_transform,
+    validate_architectures,
+)
 from snapcraft.providers import SNAPCRAFT_BASE_TO_PROVIDER_BASE
 from snapcraft.utils import get_effective_base, get_host_architecture
 
@@ -170,7 +173,8 @@ def _extra_yaml_transform(
     ) -> dict[str, Any]:
         arch = build_on
         target_arch = build_for if build_for else get_host_architecture()
-        return apply_extensions(yaml_data, arch=arch, target_arch=target_arch)
+        new_yaml_data = apply_extensions(yaml_data, arch=arch, target_arch=target_arch)
+        return apply_root_packages_transform(new_yaml_data)
 
     @override
     def _get_dispatcher(self) -> craft_cli.Dispatcher:

snapcraft/models/project.py

@@ -16,6 +16,7 @@
 
 """Project file definition and helpers."""
 
+import copy
 import re
 from typing import TYPE_CHECKING, Any, Dict, List, Literal, Optional, Tuple, Union, cast
 
@@ -171,6 +172,32 @@ def _validate_architectures_all_keyword(architectures):
             )
 
 
+def apply_root_packages_transform(yaml_data: dict[str, Any]) -> dict[str, Any]:
+    """Support Root Packages in Snapcraft.
+
+    This allows the user to use "build-packages" and "build-snaps"
+    at the root level of the snapcraft.yaml file.
+    """
+    if "build-packages" not in yaml_data and "build-snaps" not in yaml_data:
+        return yaml_data
+
+    yaml_data = copy.deepcopy(yaml_data)
+    yaml_data.setdefault("parts", {})
+    yaml_data["parts"]["snapcraft/core"] = {"plugin": "nil"}
+
+    if "build-packages" in yaml_data:
+        yaml_data["parts"]["snapcraft/core"]["build-packages"] = yaml_data.pop(
+            "build-packages"
+        )
+
+    if "build-snaps" in yaml_data:
+        yaml_data["parts"]["snapcraft/core"]["build-snaps"] = yaml_data.pop(
+            "build-snaps"
+        )
+
+    return yaml_data
+
+
 class Socket(models.CraftBaseModel):
     """Snapcraft app socket definition."""
 

tests/unit/models/test_projects.py

@@ -29,6 +29,7 @@
     Hook,
     Project,
 )
+from snapcraft.models.project import apply_root_packages_transform
 from snapcraft.utils import get_host_architecture
 
 
@@ -1782,3 +1783,32 @@ def test_project_get_build_for_arch_triplet_all(self, project_yaml_data):
         arch_triplet = project.get_build_for_arch_triplet()
 
         assert not arch_triplet
+
+
+class TestProjectTransform:
+    """Test Transform the Project."""
+
+    def test_root_packages_transform(self, project_yaml_data):
+        """Test transforming the project."""
+        data = project_yaml_data()
+        data["build-packages"] = ["pkg1", "pkg2"]
+        data["build-snaps"] = ["snap3", "snap4"]
+
+        data_transformed = apply_root_packages_transform(data)
+
+        project = Project.unmarshal(data_transformed)
+
+        assert project.parts["snapcraft/core"]["build-packages"] == ["pkg1", "pkg2"]
+        assert project.parts["snapcraft/core"]["build-snaps"] == ["snap3", "snap4"]
+
+    def test_root_packages_transform_no_affect(self, project_yaml_data):
+        """Test transforming the project without root packages."""
+        data = project_yaml_data()
+
+        data_transformed = apply_root_packages_transform(data)
+
+        project = Project.unmarshal(data_transformed)
+
+        assert project.build_packages is None
+        assert project.build_snaps is None
+        assert "snapcraft/core" not in project.parts