feat(pypi): support aarch64 windows on pipstar (bazel-contrib#3226)

This adds the necessary bits for Windows ARM64 support when evaluating
env markers in requirements files and selecting the right wheels in
`experimental_index_url`.

Related bazel-contrib#2276

Author: aignas

CHANGELOG.md

@@ -131,6 +131,9 @@ END_UNRELEASED_TEMPLATE
   * {obj}`//python:features.bzl%features.headers_abi3` can be used to
     feature-detect the presense of the above.
 * (toolchains) Local toolchains can use a label for the interpreter to use.
+* (pypi) Support for environment marker handling and `experimental_index_url` handling for
+  Windows ARM64 for Python 3.11 and later
+  ([#2276](https://github.com/bazel-contrib/rules_python/issues/2276)).
 
 {#v1-6-3}
 ## [1.6.3] - 2025-09-21

MODULE.bazel

@@ -171,6 +171,35 @@ pip = use_extension("//python/extensions:pip.bzl", "pip")
     ]
 ]
 
+[
+    pip.default(
+        arch_name = cpu,
+        config_settings = [
+            "@platforms//cpu:{}".format(cpu),
+            "@platforms//os:windows",
+            "//python/config_settings:_is_py_freethreaded_{}".format(
+                "yes" if freethreaded else "no",
+            ),
+        ],
+        env = {"platform_version": "0"},
+        marker = "python_version >= '3.13'" if freethreaded else "python_version >= '3.11'",
+        os_name = "windows",
+        platform = "windows_{}{}".format(cpu, freethreaded),
+        whl_abi_tags = ["cp{major}{minor}t"] if freethreaded else [
+            "abi3",
+            "cp{major}{minor}",
+        ],
+        whl_platform_tags = whl_platform_tags,
+    )
+    for cpu, whl_platform_tags in {
+        "aarch64": ["win_arm64"],
+    }.items()
+    for freethreaded in [
+        "",
+        "_freethreaded",
+    ]
+]
+
 pip.parse(
     hub_name = "rules_python_publish_deps",
     python_version = "3.11",

examples/BUILD.bazel

@@ -28,3 +28,28 @@ lock(
     ],
     python_version = "3.9.19",
 )
+
+lock(
+    name = "bzlmod_requirements_3_11",
+    srcs = ["bzlmod/requirements.in"],
+    out = "bzlmod/requirements_lock_3_11.txt",
+    args = [
+        "--emit-index-url",
+        "--universal",
+        "--python-version=3.11",
+    ],
+    python_version = "3.11",
+)
+
+lock(
+    name = "bzlmod_requirements_3_11_windows",
+    srcs = ["bzlmod/requirements.in"],
+    out = "bzlmod/requirements_windows_3_11.txt",
+    args = [
+        "--emit-index-url",
+        "--python-platform",
+        "windows",
+        "--python-version=3.11",
+    ],
+    python_version = "3.11",
+)

examples/bzlmod/MODULE.bazel

@@ -169,10 +169,13 @@ pip.default(
     env = {
         "platform_version": "0",
     },
+    # Windows ARM64 support has been added only on 3.11 and above, hence, constrain
+    # the availability of the platform for those python versions.
+    marker = "python_version >= '3.11'",
     os_name = "windows",
     platform = "windows_aarch64",
     whl_abi_tags = [],  # default to all ABIs
-    whl_platform_tags = ["win_amd64"],
+    whl_platform_tags = ["win_arm64"],
 )
 
 # To fetch pip dependencies, use pip.parse. We can pass in various options,
@@ -206,14 +209,6 @@ pip.parse(
             "sphinxcontrib-serializinghtml",
         ],
     },
-    # You can use one of the values below to specify the target platform
-    # to generate the dependency graph for.
-    experimental_target_platforms = [
-        # Specifying the target platforms explicitly
-        "cp39_linux_x86_64",
-        "cp39_linux_*",
-        "cp39_*",
-    ],
     extra_hub_aliases = {
         "wheel": ["generated_file"],
     },
@@ -239,30 +234,34 @@ pip.parse(
             "sphinxcontrib-serializinghtml",
         ],
     },
-    # You can use one of the values below to specify the target platform
-    # to generate the dependency graph for.
-    experimental_target_platforms = [
-        # Using host python version
-        "linux_*",
-        "osx_*",
-        "windows_*",
-        # Or specifying an exact platform
-        "linux_x86_64",
-        # Or the following to get the `host` platform only
-        "host",
-    ],
     hub_name = "pip",
     python_version = "3.10",
     # The requirements files for each platform that we want to support.
     requirements_by_platform = {
         # Default requirements file for needs to explicitly provide the platforms
         "//:requirements_lock_3_10.txt": "linux_*,osx_*",
+        "//:requirements_windows_3_10.txt": "windows_x86_64",
+    },
+    # These modifications were created above and we
+    # are providing pip.parse with the label of the mod
+    # and the name of the wheel.
+    whl_modifications = {
+        "@whl_mods_hub//:requests.json": "requests",
+        "@whl_mods_hub//:wheel.json": "wheel",
+    },
+)
+pip.parse(
+    hub_name = "pip",
+    python_version = "3.11",
+    requirements_by_platform = {
+        # Default requirements file for needs to explicitly provide the platforms
+        "//:requirements_lock_3_11.txt": "linux_*,osx_*",
         # This API allows one to specify additional platforms that the users
         # configure the toolchains for themselves. In this example we add
         # `windows_aarch64` to illustrate that `rules_python` won't fail to
         # process the value, but it does not mean that this example will work
         # on Windows ARM.
-        "//:requirements_windows_3_10.txt": "windows_x86_64,windows_aarch64",
+        "//:requirements_windows_3_11.txt": "windows_x86_64,windows_aarch64",
     },
     # These modifications were created above and we
     # are providing pip.parse with the label of the mod