feat!: validate devel bases (#302)

Signed-off-by: Callahan Kovacs <[email protected]>

craft_application/application.py

@@ -70,6 +70,7 @@ class AppMetadata:
     """Metadata about a *craft application."""
 
     name: str
+    ProjectClass: type[models.Project]
     summary: str | None = None
     version: str = field(init=False)
     source_ignore_patterns: list[str] = field(default_factory=lambda: [])
@@ -78,7 +79,6 @@ class AppMetadata:
     project_variables: list[str] = field(default_factory=lambda: ["version"])
     mandatory_adoptable_fields: list[str] = field(default_factory=lambda: ["version"])
 
-    ProjectClass: type[models.Project] = models.Project
     BuildPlannerClass: type[models.BuildPlanner] = field(
         default=NotImplementedError  # type: ignore[assignment,type-abstract]
     )

craft_application/models/__init__.py

@@ -1,6 +1,6 @@
 # This file is part of craft_application.
 #
-# Copyright 2023 Canonical Ltd.
+# Copyright 2023-2024 Canonical Ltd.
 #
 # This program is free software: you can redistribute it and/or modify it
 # under the terms of the GNU Lesser General Public License version 3, as
@@ -25,12 +25,20 @@
 )
 from craft_application.models.grammar import GrammarAwareProject
 from craft_application.models.metadata import BaseMetadata
-from craft_application.models.project import BuildInfo, BuildPlanner, Project
+from craft_application.models.project import (
+    DEVEL_BASE_INFOS,
+    DEVEL_BASE_WARNING,
+    BuildInfo,
+    BuildPlanner,
+    Project,
+)
 
 
 __all__ = [
     "BaseMetadata",
     "BuildInfo",
+    "DEVEL_BASE_INFOS",
+    "DEVEL_BASE_WARNING",
     "CraftBaseConfig",
     "CraftBaseModel",
     "GrammarAwareProject",

craft_application/models/project.py

@@ -24,9 +24,11 @@
 import craft_parts
 import craft_providers.bases
 import pydantic
+from craft_cli import emit
 from pydantic import AnyUrl
 from typing_extensions import override
 
+from craft_application import errors
 from craft_application.models.base import CraftBaseConfig, CraftBaseModel
 from craft_application.models.constraints import (
     MESSAGE_INVALID_NAME,
@@ -39,6 +41,33 @@
 )
 
 
+@dataclasses.dataclass
+class DevelBaseInfo:
+    """Devel base information for an OS."""
+
+    current_devel_base: craft_providers.bases.BaseAlias
+    """The base that the 'devel' alias currently points to."""
+
+    devel_base: craft_providers.bases.BaseAlias
+    """The devel base."""
+
+
+# A list of DevelBaseInfo objects that define an OS's current devel base and devel base.
+DEVEL_BASE_INFOS = [
+    DevelBaseInfo(
+        # TODO: current_devel_base should point to 24.10, which is not available yet
+        current_devel_base=craft_providers.bases.ubuntu.BuilddBaseAlias.DEVEL,
+        devel_base=craft_providers.bases.ubuntu.BuilddBaseAlias.DEVEL,
+    ),
+]
+
+DEVEL_BASE_WARNING = (
+    "The development build-base should only be used for testing purposes, "
+    "as its contents are bound to change with the opening of new Ubuntu releases, "
+    "suddenly and without warning."
+)
+
+
 @dataclasses.dataclass
 class BuildInfo:
     """Platform build information."""
@@ -115,6 +144,51 @@ def effective_base(self) -> Any:  # noqa: ANN401 app specific classes can improv
             return self.base
         raise RuntimeError("Could not determine effective base")
 
+    @classmethod
+    @abc.abstractmethod
+    def _providers_base(cls, base: str) -> craft_providers.bases.BaseAlias | None:
+        """Get a BaseAlias from the application's base.
+
+        :param base: The application-specific base name.
+
+        :returns: The BaseAlias for the base or None if the base does not map to
+          a BaseAlias.
+
+        :raises CraftValidationError: If the project's base cannot be determined.
+        """
+
+    @pydantic.root_validator(  # pyright: ignore[reportUnknownMemberType,reportUntypedFunctionDecorator]
+        pre=False
+    )
+    def _validate_devel(cls, values: dict[str, Any]) -> dict[str, Any]:
+        """Validate the build-base is 'devel' for the current devel base."""
+        base = values.get("base")
+        # if there is no base, do not validate the build-base
+        if not base:
+            return values
+
+        base_alias = cls._providers_base(base)
+
+        # if the base does not map to a base alias, do not validate the build-base
+        if not base_alias:
+            return values
+
+        build_base = values.get("build_base") or base
+        build_base_alias = cls._providers_base(build_base)
+
+        # warn if a devel build-base is being used, error if a devel build-base is not
+        # used for a devel base
+        for devel_base_info in DEVEL_BASE_INFOS:
+            if base_alias == devel_base_info.current_devel_base:
+                if build_base_alias == devel_base_info.devel_base:
+                    emit.message(DEVEL_BASE_WARNING)
+                else:
+                    raise errors.CraftValidationError(
+                        f"A development build-base must be used when base is {base!r}"
+                    )
+
+        return values
+
     @override
     @classmethod
     def transform_pydantic_error(cls, error: pydantic.ValidationError) -> None:

craft_application/services/provider.py

@@ -105,7 +105,7 @@ def instance(
     ) -> Generator[craft_providers.Executor, None, None]:
         """Context manager for getting a provider instance.
 
-        :param base_name: A craft_providers capable base name (tuple of name, version)
+        :param build_info: Build information for the instance.
         :param work_dir: Local path to mount inside the provider instance.
         :param allow_unstable: Whether to allow the use of unstable images.
         :returns: a context manager of the provider instance.

tests/conftest.py

@@ -28,6 +28,7 @@
 from craft_application import application, models, services, util
 from craft_cli import EmitterMode, emit
 from craft_providers import bases
+from typing_extensions import override
 
 if TYPE_CHECKING:  # pragma: no cover
     from collections.abc import Iterator
@@ -78,29 +79,45 @@ def default_app_metadata() -> craft_application.AppMetadata:
         m.setattr(metadata, "version", lambda _: "3.14159")
         return craft_application.AppMetadata(
             "testcraft",
+            FakeProject,
             "A fake app for testing craft-application",
             BuildPlannerClass=MyBuildPlanner,
             source_ignore_patterns=["*.snap", "*.charm", "*.starcraft"],
         )
 
 
 @pytest.fixture()
-def app_metadata(features) -> craft_application.AppMetadata:
+def app_metadata(features, fake_project_class) -> craft_application.AppMetadata:
     with pytest.MonkeyPatch.context() as m:
         m.setattr(metadata, "version", lambda _: "3.14159")
         return craft_application.AppMetadata(
             "testcraft",
+            fake_project_class,
             "A fake app for testing craft-application",
             BuildPlannerClass=MyBuildPlanner,
             source_ignore_patterns=["*.snap", "*.charm", "*.starcraft"],
             features=craft_application.AppFeatures(**features),
         )
 
 
+class FakeProject(models.Project):
+    """A fake project for testing."""
+
+    @override
+    @classmethod
+    def _providers_base(cls, base: str) -> bases.BaseAlias:
+        return bases.get_base_alias(("ubuntu", "24.04"))
+
+
+@pytest.fixture()
+def fake_project_class() -> type[models.Project]:
+    return FakeProject
+
+
 @pytest.fixture()
-def fake_project() -> models.Project:
+def fake_project(fake_project_class) -> models.Project:
     arch = util.get_host_architecture()
-    return models.Project(
+    return fake_project_class(
         name="full-project",  # pyright: ignore[reportArgumentType]
         title="A fully-defined project",  # pyright: ignore[reportArgumentType]
         base="core24",