Generate project object on demand

.github/workflows/gettext.yaml

@@ -23,6 +23,10 @@ jobs:
           # exception to the branch protection, so we'll use that account's
           # token to push to the main branch.
           token: ${{ secrets.FSFE_SYSTEM_TOKEN }}
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.9"
       - name: Install gettext and wlc
         run: sudo apt-get install -y gettext wlc
       # We mostly install reuse to install the click dependency.

src/reuse/cli/annotate.py

@@ -44,7 +44,7 @@
 )
 from ..i18n import _
 from ..project import Project
-from .common import ClickObj, MutexOption, requires_project, spdx_identifier
+from .common import ClickObj, MutexOption, spdx_identifier
 from .main import main
 
 _LOGGER = logging.getLogger(__name__)
@@ -285,7 +285,6 @@ def get_reuse_info(
 )
 
 
-@requires_project
 @main.command(name="annotate", help=_HELP)
 @click.option(
     "--copyright",
@@ -449,7 +448,7 @@ def annotate(
     paths: Sequence[Path],
 ) -> None:
     # pylint: disable=too-many-arguments,too-many-locals,missing-function-docstring
-    project = cast(Project, obj.project)
+    project = obj.project
 
     test_mandatory_option_required(copyrights, licenses, contributors)
     paths = all_paths(paths, recursive, project)

src/reuse/cli/common.py

@@ -4,34 +4,67 @@
 
 """Utilities that are common to multiple CLI commands."""
 
-from dataclasses import dataclass
-from typing import Any, Callable, Mapping, Optional, TypeVar
+from dataclasses import dataclass, field
+from pathlib import Path
+from typing import Any, Mapping, Optional
 
 import click
 from boolean.boolean import Expression, ParseError
 from license_expression import ExpressionError
 
 from .._util import _LICENSING
+from ..global_licensing import GlobalLicensingParseError
 from ..i18n import _
-from ..project import Project
+from ..project import GlobalLicensingConflict, Project
+from ..vcs import find_root
 
-F = TypeVar("F", bound=Callable)
 
-
-def requires_project(f: F) -> F:
-    """A decorator to mark subcommands that require a :class:`Project` object.
-    Make sure to apply this decorator _first_.
-    """
-    setattr(f, "requires_project", True)
-    return f
-
-
-@dataclass(frozen=True)
+@dataclass()
 class ClickObj:
     """A dataclass holding necessary context and options."""
 
-    no_multiprocessing: bool
-    project: Optional[Project]
+    root: Optional[Path] = None
+    include_submodules: bool = False
+    include_meson_subprojects: bool = False
+    no_multiprocessing: bool = True
+
+    _project: Optional[Project] = field(
+        default=None, init=False, repr=False, compare=False
+    )
+
+    @property
+    def project(self) -> Project:
+        """Generate a project object on demand, and cache it."""
+        if self._project:
+            return self._project
+
+        root = self.root
+        if root is None:
+            root = find_root()
+        if root is None:
+            root = Path.cwd()
+
+        try:
+            project = Project.from_directory(
+                root,
+                include_submodules=self.include_submodules,
+                include_meson_subprojects=self.include_meson_subprojects,
+            )
+        # FileNotFoundError and NotADirectoryError don't need to be caught
+        # because argparse already made sure of these things.
+        except GlobalLicensingParseError as error:
+            raise click.UsageError(
+                _(
+                    "'{path}' could not be parsed. We received the"
+                    " following error message: {message}"
+                ).format(path=error.source, message=str(error))
+            ) from error
+
+        except (GlobalLicensingConflict, OSError) as error:
+            raise click.UsageError(str(error)) from error
+
+        self._project = project
+        return project
 
 
 class MutexOption(click.Option):

src/reuse/cli/convert_dep5.py

@@ -12,8 +12,7 @@
 from ..convert_dep5 import toml_from_dep5
 from ..global_licensing import ReuseDep5
 from ..i18n import _
-from ..project import Project
-from .common import ClickObj, requires_project
+from .common import ClickObj
 from .main import main
 
 _HELP = _(
@@ -23,12 +22,11 @@
 )
 
 
-@requires_project
 @main.command(name="convert-dep5", help=_HELP)
 @click.pass_obj
 def convert_dep5(obj: ClickObj) -> None:
     # pylint: disable=missing-function-docstring
-    project = cast(Project, obj.project)
+    project = obj.project
     if not (project.root / ".reuse/dep5").exists():
         raise click.UsageError(_("No '.reuse/dep5' file."))
 

src/reuse/cli/download.py

@@ -9,18 +9,17 @@
 import sys
 from difflib import SequenceMatcher
 from pathlib import Path
-from typing import IO, Collection, Optional, cast
+from typing import IO, Collection, Optional
 from urllib.error import URLError
 
 import click
 
 from .._licenses import ALL_NON_DEPRECATED_MAP
 from ..download import _path_to_license_file, put_license_in_file
 from ..i18n import _
-from ..project import Project
 from ..report import ProjectReport
 from ..types import StrPath
-from .common import ClickObj, MutexOption, requires_project
+from .common import ClickObj, MutexOption
 from .main import main
 
 _LOGGER = logging.getLogger(__name__)
@@ -113,7 +112,6 @@ def _successfully_downloaded(destination: StrPath) -> None:
 )
 
 
-@requires_project
 @main.command(name="download", help=_HELP)
 @click.option(
     "--all",
@@ -166,9 +164,7 @@ def download(
 
     if all_:
         # TODO: This is fairly inefficient, but gets the job done.
-        report = ProjectReport.generate(
-            cast(Project, obj.project), do_checksum=False
-        )
+        report = ProjectReport.generate(obj.project, do_checksum=False)
         licenses = report.missing_licenses.keys()
 
     if len(licenses) > 1 and output:

src/reuse/cli/lint.py

@@ -10,16 +10,14 @@
 """Click code for lint subcommand."""
 
 import sys
-from typing import cast
 
 import click
 
 from .. import __REUSE_version__
 from ..i18n import _
 from ..lint import format_json, format_lines, format_plain
-from ..project import Project
 from ..report import ProjectReport
-from .common import ClickObj, MutexOption, requires_project
+from .common import ClickObj, MutexOption
 from .main import main
 
 _OUTPUT_MUTEX = ["quiet", "json", "plain", "lines"]
@@ -62,7 +60,6 @@
 )
 
 
-@requires_project
 @main.command(name="lint", help=_HELP)
 @click.option(
     "--quiet",
@@ -102,7 +99,7 @@ def lint(
 ) -> None:
     # pylint: disable=missing-function-docstring
     report = ProjectReport.generate(
-        cast(Project, obj.project),
+        obj.project,
         do_checksum=False,
         multiprocessing=not obj.no_multiprocessing,
     )

src/reuse/cli/lint_file.py

@@ -9,15 +9,14 @@
 
 import sys
 from pathlib import Path
-from typing import Collection, cast
+from typing import Collection
 
 import click
 
 from ..i18n import _
 from ..lint import format_lines_subset
-from ..project import Project
 from ..report import ProjectSubsetReport
-from .common import ClickObj, MutexOption, requires_project
+from .common import ClickObj, MutexOption
 from .main import main
 
 _OUTPUT_MUTEX = ["quiet", "lines"]
@@ -29,7 +28,6 @@
 )
 
 
-@requires_project
 @main.command(name="lint-file", help=_HELP)
 @click.option(
     "--quiet",
@@ -58,7 +56,7 @@ def lint_file(
     obj: ClickObj, quiet: bool, lines: bool, files: Collection[Path]
 ) -> None:
     # pylint: disable=missing-function-docstring
-    project = cast(Project, obj.project)
+    project = obj.project
     subset_files = {Path(file_) for file_ in files}
     for file_ in subset_files:
         if not file_.resolve().is_relative_to(project.root.resolve()):

src/reuse/cli/main.py

@@ -21,10 +21,7 @@
 
 from .. import __REUSE_version__
 from .._util import setup_logging
-from ..global_licensing import GlobalLicensingParseError
 from ..i18n import _
-from ..project import GlobalLicensingConflict, Project
-from ..vcs import find_root
 from .common import ClickObj
 
 _PACKAGE_PATH = os.path.dirname(__file__)
@@ -146,33 +143,9 @@ def main(
     if not suppress_deprecation:
         warnings.filterwarnings("default", module="reuse")
 
-    project: Optional[Project] = None
-    if ctx.invoked_subcommand:
-        cmd = main.get_command(ctx, ctx.invoked_subcommand)
-        if getattr(cmd, "requires_project", False):
-            if root is None:
-                root = find_root()
-            if root is None:
-                root = Path.cwd()
-
-            try:
-                project = Project.from_directory(root)
-            # FileNotFoundError and NotADirectoryError don't need to be caught
-            # because argparse already made sure of these things.
-            except GlobalLicensingParseError as error:
-                raise click.UsageError(
-                    _(
-                        "'{path}' could not be parsed. We received the"
-                        " following error message: {message}"
-                    ).format(path=error.source, message=str(error))
-                ) from error
-
-            except (GlobalLicensingConflict, OSError) as error:
-                raise click.UsageError(str(error)) from error
-            project.include_submodules = include_submodules
-            project.include_meson_subprojects = include_meson_subprojects
-
     ctx.obj = ClickObj(
+        root=root,
+        include_submodules=include_submodules,
+        include_meson_subprojects=include_meson_subprojects,
         no_multiprocessing=no_multiprocessing,
-        project=project,
     )

src/reuse/cli/spdx.py

@@ -8,23 +8,21 @@
 import contextlib
 import logging
 import sys
-from typing import Optional, cast
+from typing import Optional
 
 import click
 
 from .. import _IGNORE_SPDX_PATTERNS
 from ..i18n import _
-from ..project import Project
 from ..report import ProjectReport
-from .common import ClickObj, requires_project
+from .common import ClickObj
 from .main import main
 
 _LOGGER = logging.getLogger(__name__)
 
 _HELP = _("Generate an SPDX bill of materials.")
 
 
-@requires_project
 @main.command(name="spdx", help=_HELP)
 @click.option(
     "--output",
@@ -103,7 +101,7 @@ def spdx(
         )
 
     report = ProjectReport.generate(
-        cast(Project, obj.project),
+        obj.project,
         multiprocessing=not obj.no_multiprocessing,
         add_license_concluded=add_license_concluded,
     )