WIP: a builder API for pip extension 1/n - platform defs

CHANGELOG.md

@@ -104,6 +104,8 @@ END_UNRELEASED_TEMPLATE
   Set the `RULES_PYTHON_ENABLE_PIPSTAR=1` environment variable to enable it.
 * (utils) Add a way to run a REPL for any `rules_python` target that returns
   a `PyInfo` provider.
+* (pypi) Added early developer preview `pip.default` tag class in order to customize what
+  platforms are enabled. Only `rules_python` and root modules can use this feature.
 
 {#v0-0-0-removed}
 ### Removed

MODULE.bazel

@@ -56,10 +56,70 @@ use_repo(
 # This call registers the Python toolchains.
 register_toolchains("@pythons_hub//:all")
 
+# Let's define default platforms for our users first
+pip = use_extension("//python/extensions:pip.bzl", "pip")
+
+_DEFAULT_LINUX_PLATFORM_VERSION = "0"
+
+_DEFAULT_OSX_PLATFORM_VERSION = "14.0"
+
+_DEFAULT_WINDOWS_PLATFORM_VERSION = "0"
+
+[
+    pip.default(
+        arch_name = cpu,
+        constraint_values = [
+            "@platforms//os:linux",
+            "@platforms//cpu:{}".format(cpu),
+        ],
+        env_platform_version = _DEFAULT_LINUX_PLATFORM_VERSION,
+        os_name = "linux",
+        platform = "linux_{}".format(cpu),
+    )
+    # TODO @aignas 2025-05-19: only leave tier 0-1 cpus when stabilizing the
+    # `pip.default` extension
+    for cpu in [
+        "aarch64",
+        "arm",
+        "ppc",
+        "s390x",
+        "x86_64",
+    ]
+]
+
+[
+    pip.default(
+        arch_name = cpu,
+        constraint_values = [
+            "@platforms//os:osx",
+            "@platforms//cpu:{}".format(cpu),
+        ],
+        # We choose the oldest non-EOL version at the time when we release `rules_python`.
+        # See https://endoflife.date/macos
+        env_platform_version = _DEFAULT_OSX_PLATFORM_VERSION,
+        os_name = "osx",
+        platform = "osx_{}".format(cpu),
+    )
+    for cpu in [
+        "aarch64",
+        "x86_64",
+    ]
+]
+
+pip.default(
+    arch_name = "x86_64",
+    constraint_values = [
+        "@platforms//os:windows",
+        "@platforms//cpu:x86_64",
+    ],
+    env_platform_version = _DEFAULT_WINDOWS_PLATFORM_VERSION,
+    os_name = "windows",
+    platform = "windows_x86_64",
+)
+
 #####################
-# Install twine for our own runfiles wheel publishing and allow bzlmod users to use it.
+# Then install twine for our own runfiles wheel publishing and allow bzlmod users to use it.
 
-pip = use_extension("//python/extensions:pip.bzl", "pip")
 pip.parse(
     # NOTE @aignas 2024-10-26: We have an integration test that depends on us
     # being able to build sdists for this hub, so explicitly set this to False.

python/private/pypi/evaluate_markers.bzl

@@ -15,9 +15,7 @@
 """A simple function that evaluates markers using a python interpreter."""
 
 load(":deps.bzl", "record_files")
-load(":pep508_env.bzl", "env")
 load(":pep508_evaluate.bzl", "evaluate")
-load(":pep508_platform.bzl", "platform_from_str")
 load(":pep508_requirement.bzl", "requirement")
 load(":pypi_repo_utils.bzl", "pypi_repo_utils")
 
@@ -30,22 +28,26 @@ SRCS = [
     Label("//python/private/pypi/whl_installer:platform.py"),
 ]
 
-def evaluate_markers(requirements, python_version = None):
+def evaluate_markers(*, requirements, platforms):
     """Return the list of supported platforms per requirements line.
 
     Args:
         requirements: {type}`dict[str, list[str]]` of the requirement file lines to evaluate.
-        python_version: {type}`str | None` the version that can be used when evaluating the markers.
+        platforms: {type}`dict[str | struct]` TODO
 
     Returns:
         dict of string lists with target platforms
     """
     ret = {}
-    for req_string, platforms in requirements.items():
+    for req_string, platform_strings in requirements.items():
         req = requirement(req_string)
-        for platform in platforms:
-            if evaluate(req.marker, env = env(platform_from_str(platform, python_version))):
-                ret.setdefault(req_string, []).append(platform)
+        for platform_str in platform_strings:
+            env = platforms.get(platform_str)
+            if not env:
+                fail("Please define platform: '{}'".format(platform_str))
+
+            if evaluate(req.marker, env = env):
+                ret.setdefault(req_string, []).append(platform_str)
 
     return ret