feat: Warn when a dependency set is unused

.pre-commit-hooks.yaml

@@ -5,3 +5,4 @@
     language: python
     files: "dependencies.yaml"
     pass_filenames: false
+    args: [-Wall, -Werror]

src/rapids_dependency_file_generator/__init__.py

@@ -5,13 +5,15 @@
 a Conda environment from ``dependencies.yaml``.
 """
 
-from . import _config, _rapids_dependency_file_generator
+from . import _config, _rapids_dependency_file_generator, _warnings
 from ._config import *  # noqa: F401,F403
 from ._rapids_dependency_file_generator import *  # noqa: F401,F403
 from ._version import __version__
+from ._warnings import *  # noqa: F401,F403
 
 __all__ = [
     "__version__",
     *_config.__all__,
     *_rapids_dependency_file_generator.__all__,
+    *_warnings.__all__,
 ]

src/rapids_dependency_file_generator/_cli.py

@@ -1,12 +1,15 @@
 import argparse
 import os
+import warnings
 
+from . import DependencyFileGeneratorWarning
 from ._config import Output, load_config_from_file
 from ._constants import cli_name, default_dependency_file_path
 from ._rapids_dependency_file_generator import (
     delete_existing_files,
     make_dependency_files,
 )
+from ._rapids_dependency_file_validator import UnusedDependencySetWarning
 from ._version import __version__ as version
 
 
@@ -80,6 +83,27 @@ def validate_args(argv):
         help="Show the version and exit.",
     )
 
+    parser.add_argument(
+        "--warn-all",
+        default=False,
+        action="store_true",
+        help="Activate all warnings.",
+    )
+
+    parser.add_argument(
+        "--warn-unused-dependencies",
+        default=False,
+        action="store_true",
+        help="Warn if there are unused dependency sets.",
+    )
+
+    parser.add_argument(
+        "--strict",
+        default=False,
+        action="store_true",
+        help="Treat warnings as errors.",
+    )
+
     args = parser.parse_args(argv)
 
     dependent_arg_keys = ["file_key", "output", "matrix"]
@@ -118,6 +142,11 @@ def main(argv=None) -> None:
         print(f"{cli_name}, version {version}")
         return
 
+    if args.strict:
+        warnings.simplefilter("error", category=DependencyFileGeneratorWarning)
+    if not args.warn_unused_dependencies and not args.warn_all:
+        warnings.simplefilter("ignore", category=UnusedDependencySetWarning)
+
     parsed_config = load_config_from_file(args.config)
 
     matrix = generate_matrix(args.matrix)

src/rapids_dependency_file_generator/_rapids_dependency_file_validator.py

@@ -5,10 +5,13 @@
 import sys
 import textwrap
 import typing
+import warnings
 
 import jsonschema
 from jsonschema.exceptions import best_match
 
+from ._warnings import UnusedDependencySetWarning
+
 SCHEMA = json.loads(importlib.resources.files(__package__).joinpath("schema.json").read_bytes())
 
 
@@ -32,3 +35,10 @@ def validate_dependencies(dependencies: dict[str, typing.Any]) -> None:
         best_matching_error = best_match(errors)
         print("\n", textwrap.indent(str(best_matching_error), "\t"), "\n", file=sys.stderr)
         raise RuntimeError("The provided dependencies data is invalid.")
+
+    unused_dependency_sets = set(dependencies["dependencies"].keys())
+    unused_dependency_sets.difference_update(
+        i for file_config in dependencies["files"].values() for i in file_config["includes"]
+    )
+    for dep in sorted(unused_dependency_sets):
+        warnings.warn(f'Dependency set "{dep}" is not referred to anywhere in "files:"', UnusedDependencySetWarning)

src/rapids_dependency_file_generator/_warnings.py

@@ -0,0 +1,11 @@
+__all__ = [
+    "DependencyFileGeneratorWarning",
+]
+
+
+class DependencyFileGeneratorWarning(UserWarning):
+    pass
+
+
+class UnusedDependencySetWarning(DependencyFileGeneratorWarning):
+    pass

tests/test_cli.py

@@ -1,6 +1,11 @@
+import contextlib
+import os.path
+from textwrap import dedent
+
 import pytest
 
-from rapids_dependency_file_generator._cli import generate_matrix, validate_args
+from rapids_dependency_file_generator._cli import generate_matrix, main, validate_args
+from rapids_dependency_file_generator._rapids_dependency_file_validator import UnusedDependencySetWarning
 
 
 def test_generate_matrix():
@@ -181,3 +186,52 @@ def test_validate_args():
 
     args = validate_args(["--version"])
     assert args.version
+
+
+@pytest.mark.parametrize(
+    ["extra_args", "context"],
+    [
+        (
+            [],
+            contextlib.nullcontext(),
+        ),
+        (
+            ["--strict"],
+            contextlib.nullcontext(),
+        ),
+        (
+            ["--warn-unused-dependencies"],
+            pytest.warns(UnusedDependencySetWarning),
+        ),
+        (
+            ["--warn-unused-dependencies", "--strict"],
+            pytest.raises(UnusedDependencySetWarning),
+        ),
+        (
+            ["--warn-all"],
+            pytest.warns(UnusedDependencySetWarning),
+        ),
+        (
+            ["--warn-all", "--strict"],
+            pytest.raises(UnusedDependencySetWarning),
+        ),
+    ],
+)
+def test_warnings(tmp_path, extra_args, context):
+    config_file = os.path.join(tmp_path, "dependencies.yaml")
+    with open(config_file, "w") as f:
+        f.write(dedent("""
+        files:
+          all:
+            output: conda
+            includes: [a]
+        channels: []
+        dependencies:
+          a:
+            common: []
+          b:
+            common: []
+        """))
+
+    with context:
+        main(["--config", config_file, *extra_args])

tests/test_rapids_dependency_file_validator.py

@@ -0,0 +1,33 @@
+import pytest
+from rapids_dependency_file_generator._rapids_dependency_file_validator import UnusedDependencySetWarning, validate_dependencies
+
+
+def test_validate_dependencies_warn_on_unused_deps():
+    with pytest.warns(UnusedDependencySetWarning) as warnings:
+        validate_dependencies({
+            "files": {
+                "all": {
+                    "output": "conda",
+                    "includes": ["a", "b"],
+                }
+            },
+            "channels": [],
+            "dependencies": {
+                "a": {
+                    "common": [],
+                },
+                "b": {
+                    "common": [],
+                },
+                "d": {
+                    "common": [],
+                },
+                "c": {
+                    "common": [],
+                },
+            },
+        })
+
+    assert len(warnings) == 2
+    assert warnings[0].message.args[0] == 'Dependency set "c" is not referred to anywhere in "files:"'
+    assert warnings[1].message.args[0] == 'Dependency set "d" is not referred to anywhere in "files:"'