Move mindeps generation logic to separate function

resolver/mindeps/__init__.py

@@ -1,15 +1,6 @@
 # SPDX-License-Identifier: MIT
 
-import operator
+from resolver.mindeps.__main__ import entrypoint, get_min_deps  # noqa: F401
 
-from typing import Iterable, Sequence
 
-import resolver
-
-
-class MinimumDependencyProvider(resolver.Provider):
-    def sort_candidates(
-        self,
-        candidates: Iterable[resolver.Candidate],
-    ) -> Sequence[resolver.Candidate]:
-        return sorted(candidates, key=operator.attrgetter('version'), reverse=False)
+__all__ = ('entrypoint', 'get_min_deps')

resolver/mindeps/__main__.py

@@ -1,12 +1,13 @@
 # SPDX-License-Identifier: MIT
 
 import argparse
+import operator
 import os
 import os.path
 import pathlib
 import tempfile
 
-from typing import Iterable, Sequence, Set
+from typing import Dict, Iterable, List, Optional, Sequence, Set
 
 import packaging.markers
 import packaging.requirements
@@ -91,39 +92,43 @@ def main_parser() -> argparse.ArgumentParser:
     return parser
 
 
-def task() -> None:  # noqa: C901
-    parser = main_parser()
-    args = parser.parse_args()
+class MinimumDependencyProvider(resolver.Provider):
+    def sort_candidates(
+        self,
+        candidates: Iterable[resolver.Candidate],
+    ) -> Sequence[resolver.Candidate]:
+        return sorted(candidates, key=operator.attrgetter('version'), reverse=False)
 
-    if args.requirements:
-        for bad_arg in _MARKER_KEYS + ('extras',):
-            if bad_arg in args:
-                resolver.__main__._error(f'Option --{bad_arg} not supported when specifying bare requirements')
 
-    reporter = resolver.__main__.VerboseReporter if args.verbose else resolvelib.BaseReporter
+def get_min_deps(
+    requirements: List[str],
+    reporter: Optional[resolvelib.BaseReporter] = None,
+    extras: Optional[Set[str]] = None,
+    markers: Optional[Dict[str, str]] = None
+) -> Dict[str, str]:
+    reporter = reporter or resolvelib.BaseReporter
     package_resolver = resolvelib.Resolver(
-        resolver.mindeps.MinimumDependencyProvider(
+        MinimumDependencyProvider(
             '/tmp/resolver-cache' if os.name == 'posix' else None
         ),
         reporter(),
     )
 
     requirements: Iterable[packaging.requirements.Requirement] = map(
-        packaging.requirements.Requirement,
-        args.requirements or _project_requirements(),
+        packaging.requirements.Requirement, requirements
     )
 
-    extras = set(vars(args).get('extras', {})) | {''}
-    if any(arg in _MARKER_KEYS for arg in vars(args)):
+    extras = extras.copy() | {''} if extras else {''}
+    if markers is not None and any(marker in _MARKER_KEYS for marker in markers):
         marker_env = {
-            k: v for k, v in vars(args).items()
+            k: v for k, v in markers.items()
             if k in _MARKER_KEYS
         }
     else:
         marker_env = packaging.markers.default_environment()
 
     resolver_requirements: Set[packaging.requirements.Requirement] = set()
-    for requirement in requirements:
+    for requirement in list(requirements):
         for extra in extras:
             if not requirement.marker:
                 resolver_requirements.add(requirement)
@@ -133,13 +138,34 @@ def task() -> None:  # noqa: C901
 
     result = package_resolver.resolve(resolver_requirements)
 
-    if args.verbose:
-        print('\n--- Solution ---')
-
     pinned = {
         candidate.name: candidate.version
         for candidate in result.mapping.values()
     }
+
+    return pinned
+
+
+def task() -> None:  # noqa: C901
+    parser = main_parser()
+    args = parser.parse_args()
+
+    if args.requirements:
+        for bad_arg in _MARKER_KEYS + ('extras',):
+            if bad_arg in args:
+                resolver.__main__._error(f'Option --{bad_arg} not supported when specifying bare requirements')
+
+    reporter = resolver.__main__.VerboseReporter if args.verbose else resolvelib.BaseReporter
+
+    if args.verbose:
+        print('\n--- Solution ---')
+
+    pinned = get_min_deps(
+        args.requirements or _project_requirements(),
+        reporter=reporter,
+        extras=set(vars(args).get('extras', {})),
+        markers=vars(args)
+    )
     for name, version in pinned.items():
         print(f'{name}=={str(version)}')