refactor: lazy load and use entry points (#1)

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

Author: henryiii

pyproject.toml

@@ -61,6 +61,13 @@ Changelog = "https://github.com/scikit-build/scikit-build-cli/releases"
 [project.scripts]
 skbuild = "scikit_build_cli.__main__:run_cli"
 
+[project.entry-points."skbuild.commands"]
+build = "scikit_build_cli.commands.build:build"
+configure = "scikit_build_cli.commands.configure:configure"
+dynamic-metadata = "scikit_build_cli.commands.dynamic_metadata:dynamic_metadata"
+metadata = "scikit_build_cli.commands.metadata:metadata"
+install = "scikit_build_cli.commands.install:install"
+
 [tool.hatch]
 version.source = "vcs"
 build.hooks.vcs.version-file = "src/scikit_build_cli/_version.py"

src/scikit_build_cli/commands/__init__.py

@@ -4,8 +4,7 @@
 
 import click
 
-from .main import skbuild
-from .utils import _build_dir
+from ..utils import _build_dir
 
 if TYPE_CHECKING:
     from pathlib import Path
@@ -17,7 +16,7 @@ def __dir__() -> list[str]:
     return __all__
 
 
-@skbuild.command()
+@click.command()
 @_build_dir
 @click.pass_context
 def build(ctx: click.Context, build_dir: Path) -> None:  # noqa: ARG001

src/scikit_build_cli/build.py src/scikit_build_cli/commands/build.pysrc/scikit_build_cli/build.py renamed to src/scikit_build_cli/commands/build.py

@@ -4,8 +4,7 @@
 
 import click
 
-from .main import skbuild
-from .utils import _build_dir
+from ..utils import _build_dir
 
 if TYPE_CHECKING:
     from pathlib import Path
@@ -17,7 +16,7 @@ def __dir__() -> list[str]:
     return __all__
 
 
-@skbuild.command()
+@click.command()
 @_build_dir
 @click.pass_context
 def configure(ctx: click.Context, build_dir: Path) -> None:  # noqa: ARG001

src/scikit_build_cli/configure.py …c/scikit_build_cli/commands/configure.pysrc/scikit_build_cli/configure.py renamed to src/scikit_build_cli/commands/configure.py src/scikit_build_cli/configure.py renamed to src/scikit_build_cli/commands/configure.py

@@ -2,16 +2,14 @@
 
 import click
 
-from .main import skbuild
-
 __all__: list[str] = ["dynamic_metadata"]
 
 
 def __dir__() -> list[str]:
     return __all__
 
 
-@skbuild.command()
+@click.command()
 @click.pass_context
 def dynamic_metadata(ctx: click.Context) -> None:  # noqa: ARG001
     """

src/scikit_build_cli/dynamic_metadata.py …t_build_cli/commands/dynamic_metadata.pysrc/scikit_build_cli/dynamic_metadata.py renamed to src/scikit_build_cli/commands/dynamic_metadata.py src/scikit_build_cli/dynamic_metadata.py renamed to src/scikit_build_cli/commands/dynamic_metadata.py

@@ -4,8 +4,7 @@
 
 import click
 
-from .main import skbuild
-from .utils import _build_dir
+from ..utils import _build_dir
 
 if TYPE_CHECKING:
     from pathlib import Path
@@ -17,7 +16,7 @@ def __dir__() -> list[str]:
     return __all__
 
 
-@skbuild.command()
+@click.command()
 @_build_dir
 @click.pass_context
 def install(ctx: click.Context, build_dir: Path) -> None:  # noqa: ARG001

src/scikit_build_cli/install.py src/scikit_build_cli/commands/install.pysrc/scikit_build_cli/install.py renamed to src/scikit_build_cli/commands/install.py

@@ -2,16 +2,14 @@
 
 import click
 
-from .main import skbuild
-
 __all__: list[str] = ["metadata"]
 
 
 def __dir__() -> list[str]:
     return __all__
 
 
-@skbuild.command()
+@click.command()
 @click.pass_context
 def metadata(ctx: click.Context) -> None:  # noqa: ARG001
     """

src/scikit_build_cli/metadata.py src/scikit_build_cli/commands/metadata.pysrc/scikit_build_cli/metadata.py renamed to src/scikit_build_cli/commands/metadata.py

@@ -1,7 +1,8 @@
 from __future__ import annotations
 
 import pathlib
-import sys
+from collections.abc import MutableMapping, Sequence
+from importlib.metadata import EntryPoint
 
 import click
 
@@ -15,7 +16,47 @@ def __dir__() -> list[str]:
     return __all__
 
 
-@click.group("skbuild")
+class LazyGroup(click.Group):
+    """
+    Lazy loader for click commands. Based on Click's documentation, but uses
+    EntryPoints.
+    """
+
+    def __init__(
+        self,
+        name: str | None = None,
+        commands: MutableMapping[str, click.Command]
+        | Sequence[click.Command]
+        | None = None,
+        *,
+        lazy_subcommands: Sequence[EntryPoint] = (),
+        **kwargs: object,
+    ):
+        super().__init__(name, commands, **kwargs)
+        self.lazy_subcommands = {v.name: v for v in lazy_subcommands}
+
+    def list_commands(self, ctx: click.Context) -> list[str]:
+        return sorted([*super().list_commands(ctx), *self.lazy_subcommands])
+
+    def get_command(self, ctx: click.Context, cmd_name: str) -> click.Command | None:
+        if cmd_name in self.lazy_subcommands:
+            return self._lazy_load(cmd_name)
+        return super().get_command(ctx, cmd_name)
+
+    def _lazy_load(self, cmd_name: str) -> click.Command:
+        ep = self.lazy_subcommands[cmd_name]
+        cmd_object = ep.load()
+        if not isinstance(cmd_object, click.Command):
+            msg = f"Lazy loading of {ep} failed by returning a non-command object"
+            raise ValueError(msg)
+        return cmd_object
+
+
+# Add all plugin commands.
+CMDS = list(metadata.entry_points(group="skbuild.commands"))
+
+
+@click.group("skbuild", cls=LazyGroup, lazy_subcommands=CMDS)
 @click.version_option(__version__)
 @click.option(
     "--root",
@@ -27,26 +68,11 @@ def __dir__() -> list[str]:
         writable=True,
         path_type=pathlib.Path,
     ),
-    help="Path to the python project's root",
+    help="Path to the Python project's root",
 )
 @click.pass_context
 def skbuild(ctx: click.Context, root: pathlib.Path) -> None:  # noqa: ARG001
     """
     scikit-build Main CLI interface
     """
     # TODO: Add specific implementations
-
-
-# Add all plugin commands. Native subcommands are loaded in the package's __init__
-for ep in metadata.entry_points(group="skbuild.commands"):
-    try:
-        # Entry point can either point to a whole module or the decorated command
-        if not ep.attr:
-            # If it's a module, just load the module. It should have the necessary `skbuild.command` interface
-            ep.load()
-        else:
-            # Otherwise assume it is a decorated command that needs to be loaded manually
-            skbuild.add_command(ep.load())
-    except Exception as err:
-        # TODO: the print should go through the click logging interface
-        print(f"Could not load cli plugin: {ep}\n{err}", file=sys.stderr)  # noqa: T201

src/scikit_build_cli/main.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import functools
 import pathlib
 from typing import TYPE_CHECKING
 
@@ -20,25 +19,15 @@ def __dir__() -> list[str]:
     return __all__
 
 
-def _build_dir(func: F) -> F:
-    """Add build_dir click option"""
-
-    @click.option(
-        "--build-dir",
-        "-B",
-        type=click.Path(
-            exists=True,
-            file_okay=False,
-            dir_okay=True,
-            writable=True,
-            path_type=pathlib.Path,
-        ),
-        help="Path to cmake build directory",
-    )
-    @functools.wraps(func)
-    # TODO: Fix mypy checks here.
-    #  See upstream approach: https://github.com/pallets/click/blob/main/src/click/decorators.py
-    def wrapper(*args, **kwargs):  # type: ignore[no-untyped-def]
-        return func(*args, **kwargs)
-
-    return wrapper  # type: ignore[return-value]
+_build_dir = click.option(
+    "--build-dir",
+    "-B",
+    type=click.Path(
+        exists=True,
+        file_okay=False,
+        dir_okay=True,
+        writable=True,
+        path_type=pathlib.Path,
+    ),
+    help="Path to cmake build directory",
+)