Allow ignoring sub-dependencies

news/9948.feature.rst

@@ -0,0 +1,7 @@
+Implement the ``--no-deps-for`` switch for the ``install`` command and the
+requirements file. This switch will prevent the installation of dependencies of
+specific packages, as opposed to the ``--no-deps`` switch which prevents the
+installation dependencies of all requested packages.
+
+Also implement recognition of the global ``--no-deps`` switch in the requirements
+file.

src/pip/_internal/cli/cmdoptions.py

@@ -529,6 +529,30 @@ def only_binary() -> Option:
     )
 
 
+def _handle_no_deps_for(
+    option: object,
+    opt_str: str,
+    value: str,
+    parser: OptionParser,
+) -> None:
+    # ignore_dependencies_for is a set of strings
+    values = value.split(",")
+    parser.values.ignore_dependencies_for.update(values)
+
+
+def no_deps_for() -> PipOption:
+    return PipOption(
+        "--no-deps-for",
+        dest="ignore_dependencies_for",
+        action="callback",
+        callback=_handle_no_deps_for,
+        type="package_name",
+        default=set(),
+        help="Do not install sub dependencies of the named package or packages. "
+        "Accepts comma separated list of values. Can be supplied multiple times.",
+    )
+
+
 platforms: Callable[..., Option] = partial(
     Option,
     "--platform",

src/pip/_internal/cli/req_command.py

@@ -79,7 +79,12 @@ class RequirementCommand(IndexGroupCommand):
     def __init__(self, *args: Any, **kw: Any) -> None:
         super().__init__(*args, **kw)
 
-        self.cmd_opts.add_option(cmdoptions.no_clean())
+        self.cmd_opts.add_options(
+            [
+                cmdoptions.no_clean(),
+                cmdoptions.no_deps_for(),
+            ]
+        )
 
     @staticmethod
     def determine_resolver_variant(options: Values) -> str:
@@ -186,6 +191,7 @@ def make_resolver(
                 force_reinstall=force_reinstall,
                 upgrade_strategy=upgrade_strategy,
                 py_version_info=py_version_info,
+                ignore_dependencies_for=options.ignore_dependencies_for,
             )
         import pip._internal.resolution.legacy.resolver
 
@@ -201,6 +207,7 @@ def make_resolver(
             force_reinstall=force_reinstall,
             upgrade_strategy=upgrade_strategy,
             py_version_info=py_version_info,
+            ignore_dependencies_for=options.ignore_dependencies_for,
         )
 
     def get_requirements(

src/pip/_internal/commands/install.py

@@ -441,7 +441,8 @@ def run(self, options: Values, args: List[str]) -> int:
             # Check for conflicts in the package set we're installing.
             conflicts: Optional[ConflictDetails] = None
             should_warn_about_conflicts = (
-                not options.ignore_dependencies and options.warn_about_conflicts
+                not (options.ignore_dependencies or options.ignore_dependencies_for)
+                and options.warn_about_conflicts
             )
             if should_warn_about_conflicts:
                 conflicts = self._determine_conflicts(to_install)

src/pip/_internal/req/req_file.py

@@ -56,6 +56,8 @@
     cmdoptions.find_links,
     cmdoptions.no_binary,
     cmdoptions.only_binary,
+    cmdoptions.no_deps,
+    cmdoptions.no_deps_for,
     cmdoptions.prefer_binary,
     cmdoptions.require_hashes,
     cmdoptions.pre,
@@ -225,6 +227,8 @@ def handle_option_line(
             options.features_enabled.extend(
                 f for f in opts.features_enabled if f not in options.features_enabled
             )
+        options.ignore_dependencies |= opts.ignore_dependencies
+        options.ignore_dependencies_for.update(opts.ignore_dependencies_for)
 
     # set finder options
     if finder:

src/pip/_internal/resolution/legacy/resolver.py

@@ -14,7 +14,7 @@
 import sys
 from collections import defaultdict
 from itertools import chain
-from typing import DefaultDict, Iterable, List, Optional, Set, Tuple
+from typing import Container, DefaultDict, Iterable, List, Optional, Set, Tuple
 
 from pip._vendor.packaging import specifiers
 from pip._vendor.packaging.requirements import Requirement
@@ -126,6 +126,7 @@ def __init__(
         force_reinstall: bool,
         upgrade_strategy: str,
         py_version_info: Optional[Tuple[int, ...]] = None,
+        ignore_dependencies_for: Container[str] = frozenset(),
     ) -> None:
         super().__init__()
         assert upgrade_strategy in self._allowed_strategies
@@ -136,6 +137,7 @@ def __init__(
             py_version_info = normalize_version_info(py_version_info)
 
         self._py_version_info = py_version_info
+        self.ignore_dependencies_for = ignore_dependencies_for
 
         self.preparer = preparer
         self.finder = finder
@@ -542,7 +544,11 @@ def add_req(subreq: Requirement, extras_requested: Iterable[str]) -> None:
                     requirement_set, req_to_install, parent_req_name=None
                 )
 
-            if not self.ignore_dependencies:
+            ignore_dependencies = (
+                self.ignore_dependencies
+                or dist.canonical_name in self.ignore_dependencies_for
+            )
+            if not ignore_dependencies:
                 if req_to_install.extras:
                     logger.debug(
                         "Installing extra requirements: %r",

src/pip/_internal/resolution/resolvelib/provider.py

@@ -3,6 +3,7 @@
 from functools import lru_cache
 from typing import (
     TYPE_CHECKING,
+    Container,
     Dict,
     Iterable,
     Iterator,
@@ -94,10 +95,12 @@ def __init__(
         ignore_dependencies: bool,
         upgrade_strategy: str,
         user_requested: Dict[str, int],
+        ignore_dependencies_for: Container[str] = frozenset(),
     ) -> None:
         self._factory = factory
         self._constraints = constraints
         self._ignore_dependencies = ignore_dependencies
+        self._ignore_dependencies_for = ignore_dependencies_for
         self._upgrade_strategy = upgrade_strategy
         self._user_requested = user_requested
         self._known_depths: Dict[str, float] = collections.defaultdict(lambda: math.inf)
@@ -243,7 +246,10 @@ def is_satisfied_by(self, requirement: Requirement, candidate: Candidate) -> boo
         return requirement.is_satisfied_by(candidate)
 
     def get_dependencies(self, candidate: Candidate) -> Sequence[Requirement]:
-        with_requires = not self._ignore_dependencies
+        ignore_dependencies = (
+            self._ignore_dependencies or candidate.name in self._ignore_dependencies_for
+        )
+        with_requires = not ignore_dependencies
         return [r for r in candidate.iter_dependencies(with_requires) if r is not None]
 
     @staticmethod

src/pip/_internal/resolution/resolvelib/resolver.py

@@ -2,7 +2,7 @@
 import functools
 import logging
 import os
-from typing import TYPE_CHECKING, Dict, List, Optional, Set, Tuple, cast
+from typing import TYPE_CHECKING, Container, Dict, List, Optional, Set, Tuple, cast
 
 from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.resolvelib import BaseReporter, ResolutionImpossible
@@ -51,6 +51,7 @@ def __init__(
         force_reinstall: bool,
         upgrade_strategy: str,
         py_version_info: Optional[Tuple[int, ...]] = None,
+        ignore_dependencies_for: Container[str] = frozenset(),
     ):
         super().__init__()
         assert upgrade_strategy in self._allowed_strategies
@@ -67,6 +68,7 @@ def __init__(
             py_version_info=py_version_info,
         )
         self.ignore_dependencies = ignore_dependencies
+        self.ignore_dependencies_for = ignore_dependencies_for
         self.upgrade_strategy = upgrade_strategy
         self._result: Optional[Result] = None
 
@@ -80,6 +82,7 @@ def resolve(
             ignore_dependencies=self.ignore_dependencies,
             upgrade_strategy=self.upgrade_strategy,
             user_requested=collected.user_requested,
+            ignore_dependencies_for=self.ignore_dependencies_for,
         )
         if "PIP_RESOLVER_DEBUG" in os.environ:
             reporter: BaseReporter = PipDebuggingReporter()

tests/functional/test_new_resolver.py

@@ -217,6 +217,81 @@ def test_new_resolver_ignore_dependencies(script: PipTestEnvironment) -> None:
     script.assert_not_installed("dep")
 
 
+def test_new_resolver_ignore_dependencies_for(script: PipTestEnvironment) -> None:
+    create_basic_wheel_for_package(
+        script,
+        "base",
+        "0.1.0",
+        depends=["dep"],
+    )
+    create_basic_wheel_for_package(
+        script,
+        "dep",
+        "0.1.0",
+    )
+    create_basic_wheel_for_package(
+        script,
+        "base2",
+        "0.1.0",
+        depends=["dep2"],
+    )
+    create_basic_wheel_for_package(
+        script,
+        "dep2",
+        "0.1.0",
+    )
+    script.pip(
+        "install",
+        "--no-cache-dir",
+        "--no-index",
+        "--no-deps-for=base",
+        "--find-links",
+        script.scratch_path,
+        "base",
+        "base2",
+        allow_stderr_error=True,
+    )
+    script.assert_installed(base="0.1.0", base2="0.1.0", dep2="0.1.0")
+    script.assert_not_installed("dep")
+
+
+def test_new_resolver_no_deps_in_requirements(
+    tmpdir: pathlib.Path,
+    script: PipTestEnvironment,
+) -> None:
+    create_basic_wheel_for_package(
+        script,
+        "base",
+        "0.1.0",
+        depends=["dep"],
+    )
+    create_basic_wheel_for_package(
+        script,
+        "dep",
+        "0.1.0",
+    )
+
+    req_file = tmpdir / "requirements.txt"
+    req_file.write_text(
+        """
+        base==0.1.0
+        --no-deps
+        """
+    )
+
+    script.pip(
+        "install",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "-r",
+        req_file,
+    )
+    script.assert_installed(base="0.1.0")
+    script.assert_not_installed("dep")
+
+
 @pytest.mark.parametrize(
     "root_dep",
     [

tests/unit/test_req_file.py

@@ -47,6 +47,8 @@ def options(session: PipSession) -> mock.Mock:
         index_url="default_url",
         format_control=FormatControl(set(), set()),
         features_enabled=[],
+        ignore_dependencies=False,
+        ignore_dependencies_for=set(),
     )
 
 
@@ -763,6 +765,43 @@ def test_join_lines(self, tmpdir: Path, finder: PackageFinder) -> None:
 
         assert finder.index_urls == ["url1", "url2"]
 
+    def test_ignore_dependencies(self, tmpdir: Path, options: mock.Mock) -> None:
+        req = tmpdir / "req1.txt"
+        req.write_text(
+            """
+            --no-deps
+            """
+        )
+
+        list(
+            parse_reqfile(
+                req,
+                session=PipSession(),
+                options=options,
+            )
+        )
+
+        assert options.ignore_dependencies
+
+    def test_ignore_dependencies_for(self, tmpdir: Path, options: mock.Mock) -> None:
+        req = tmpdir / "req1.txt"
+        req.write_text(
+            """
+            --no-deps-for=foo,bar
+            --no-deps-for=spam,eggs
+            """
+        )
+
+        list(
+            parse_reqfile(
+                req,
+                session=PipSession(),
+                options=options,
+            )
+        )
+
+        assert options.ignore_dependencies_for == {"foo", "bar", "spam", "eggs"}
+
     def test_req_file_parse_no_only_binary(
         self, data: TestData, finder: PackageFinder
     ) -> None: