Implement --no-deps in requirements files

news/9948.feature.rst

@@ -2,3 +2,6 @@ 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/req/req_file.py

@@ -56,6 +56,7 @@
     cmdoptions.find_links,
     cmdoptions.no_binary,
     cmdoptions.only_binary,
+    cmdoptions.no_deps,
     cmdoptions.no_deps_for,
     cmdoptions.prefer_binary,
     cmdoptions.require_hashes,
@@ -226,6 +227,7 @@ 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

tests/functional/test_new_resolver.py

@@ -255,6 +255,43 @@ def test_new_resolver_ignore_dependencies_for(script: PipTestEnvironment) -> Non
     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 +47,7 @@ def options(session: PipSession) -> mock.Mock:
         index_url="default_url",
         format_control=FormatControl(set(), set()),
         features_enabled=[],
+        ignore_dependencies=False,
         ignore_dependencies_for=set(),
     )
 
@@ -764,6 +765,24 @@ 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(