wip: spike the passing of constraint_values to the hub repo

Author: aignas

python/private/pypi/config_settings.bzl

@@ -113,6 +113,7 @@ def config_settings(
         osx_versions = [],
         target_platforms = [],
         name = None,
+        platform_constraint_values = {},
         **kwargs):
     """Generate all of the pip config settings.
 
@@ -128,29 +129,36 @@ def config_settings(
             config settings for.
         target_platforms (list[str]): The list of "{os}_{cpu}" for deriving
             constraint values for each condition.
+        platform_constraint_values: {type}`dict[str, list[str]]` the constraint
+            values to use instead of the default ones. This will become a mandatory
+            parameter later.
         **kwargs: Other args passed to the underlying implementations, such as
             {obj}`native`.
     """
 
     glibc_versions = [""] + glibc_versions
     muslc_versions = [""] + muslc_versions
     osx_versions = [""] + osx_versions
-    target_platforms = [("", ""), ("osx", "universal2")] + [
-        t.split("_", 1)
+    target_platforms = {
+        tuple(t.split("_", 1)): t
         for t in target_platforms
-    ]
+    }
+    target_platforms = {
+        ("", ""): [],
+        # TODO @aignas 2025-06-15: allowing universal2 and platform specific wheels in one
+        # closure is making things maybe a little bit too complicated.
+        ("osx", "universal2"): ["@platforms//os:osx"],
+    } | {
+        (os, cpu): platform_constraint_values.get(platform_name, [
+            "@platforms//os:{}".format(os),
+            "@platforms//cpu:{}".format(cpu),
+        ])
+        for (os, cpu), platform_name in target_platforms.items()
+    }
 
     for python_version in python_versions:
-        for os, cpu in target_platforms:
-            constraint_values = []
-            suffix = ""
-            if os:
-                constraint_values.append("@platforms//os:" + os)
-                suffix += "_" + os
-            if cpu:
-                suffix += "_" + cpu
-                if cpu != "universal2":
-                    constraint_values.append("@platforms//cpu:" + cpu)
+        for (os, cpu), constraint_values in target_platforms.items():
+            suffix = "_{}_{}".format(os, cpu) if os and cpu else ""
 
             _dist_config_settings(
                 suffix = suffix,

python/private/pypi/extension.bzl

@@ -372,7 +372,7 @@ def _whl_repo(*, src, whl_library_args, is_multiple_versions, download_only, net
         ),
     )
 
-def _configure(config, *, platform, os_name, arch_name, override = False, **values):
+def _configure(config, *, platform, os_name, arch_name, constraint_values, override = False, **values):
     """Set the value in the config if the value is provided"""
     config.setdefault("platforms", {})
     if platform:
@@ -383,6 +383,7 @@ def _configure(config, *, platform, os_name, arch_name, override = False, **valu
             name = platform.replace("-", "_").lower(),
             os_name = os_name,
             arch_name = arch_name,
+            constraint_values = constraint_values,
             env = {
                 k[4:]: v
                 for k, v in values.items()
@@ -414,6 +415,10 @@ def _create_config(defaults):
             env_platform_version = "0",
             os_name = "linux",
             platform = "linux_{}".format(cpu),
+            constraint_values = [
+                "@platforms//os:linux",
+                "@platforms//cpu:{}".format(cpu),
+            ],
         )
     for cpu in [
         "aarch64",
@@ -427,6 +432,10 @@ def _create_config(defaults):
             env_platform_version = "14.0",
             os_name = "osx",
             platform = "osx_{}".format(cpu),
+            constraint_values = [
+                "@platforms//os:osx",
+                "@platforms//cpu:{}".format(cpu),
+            ],
         )
 
     _configure(
@@ -435,6 +444,10 @@ def _create_config(defaults):
         env_platform_version = "0",
         os_name = "windows",
         platform = "windows_x86_64",
+        constraint_values = [
+            "@platforms//os:windows",
+            "@platforms//cpu:x86_64",
+        ],
     )
     return struct(**defaults)
 
@@ -500,6 +513,7 @@ You cannot use both the additive_build_content and additive_build_content_file a
             _configure(
                 defaults,
                 arch_name = tag.arch_name,
+                constraint_values = tag.constraint_values,
                 # The env_ values is only used if the `PIPSTAR` is enabled
                 env_implementation_name = tag.env_implementation_name,
                 env_os_name = tag.env_os_name,
@@ -684,6 +698,13 @@ You cannot use both the additive_build_content and additive_build_content_file a
             }
             for hub_name, extra_whl_aliases in extra_aliases.items()
         },
+        platform_constraint_values = {
+            hub_name: {
+                platform_name: sorted([str(Label(cv)) for cv in p.constraint_values])
+                for platform_name, p in config.platforms.items()
+            }
+            for hub_name in hub_whl_map
+        },
         whl_libraries = {
             k: dict(sorted(args.items()))
             for k, args in sorted(whl_libraries.items())
@@ -774,6 +795,7 @@ def _pip_impl(module_ctx):
                 for key, values in whl_map.items()
             },
             packages = mods.exposed_packages.get(hub_name, []),
+            platform_constraint_values = mods.platform_constraint_values.get(hub_name, {}),
             groups = mods.hub_group_map.get(hub_name),
         )
 
@@ -793,6 +815,12 @@ The CPU architecture name to be used.
 :::{note}
 Either this or {attr}`env_platform_machine` should be specified.
 :::
+""",
+    ),
+    "constraint_values": attr.label_list(
+        mandatory = True,
+        doc = """\
+The constraint_values to use in select statements.
 """,
     ),
     "os_name": attr.string(

python/private/pypi/hub_repository.bzl

@@ -34,6 +34,7 @@ def _impl(rctx):
         },
         extra_hub_aliases = rctx.attr.extra_hub_aliases,
         requirement_cycles = rctx.attr.groups,
+        platform_constraint_values = rctx.attr.platform_constraint_values,
     )
     for path, contents in aliases.items():
         rctx.file(path, contents)
@@ -83,6 +84,10 @@ hub_repository = repository_rule(
 The list of packages that will be exposed via all_*requirements macros. Defaults to whl_map keys.
 """,
         ),
+        "platform_constraint_values": attr.string_list_dict(
+            doc = "The constraint values for each platform name. The values are string canonical string Label representations",
+            mandatory = False,
+        ),
         "repo_name": attr.string(
             mandatory = True,
             doc = "The apparent name of the repo. This is needed because in bzlmod, the name attribute becomes the canonical name.",

python/private/pypi/render_pkg_aliases.bzl

@@ -155,12 +155,13 @@ def _major_minor_versions(python_versions):
     # Use a dict as a simple set
     return sorted({_major_minor(v): None for v in python_versions})
 
-def render_multiplatform_pkg_aliases(*, aliases, **kwargs):
+def render_multiplatform_pkg_aliases(*, aliases, platform_constraint_values = {}, **kwargs):
     """Render the multi-platform pkg aliases.
 
     Args:
         aliases: dict[str, list(whl_config_setting)] A list of aliases that will be
           transformed from ones having `filename` to ones having `config_setting`.
+        platform_constraint_values: {type}`dict[str, list[str]]` TODO.
         **kwargs: extra arguments passed to render_pkg_aliases.
 
     Returns:
@@ -188,17 +189,22 @@ def render_multiplatform_pkg_aliases(*, aliases, **kwargs):
         osx_versions = flag_versions.get("osx_versions", []),
         python_versions = _major_minor_versions(flag_versions.get("python_versions", [])),
         target_platforms = flag_versions.get("target_platforms", []),
+        platform_constraint_values = platform_constraint_values,
         visibility = ["//:__subpackages__"],
     )
     return contents
 
-def _render_config_settings(**kwargs):
+def _render_config_settings(platform_constraint_values, **kwargs):
     return """\
 load("@rules_python//python/private/pypi:config_settings.bzl", "config_settings")
 
 {}""".format(render.call(
         "config_settings",
         name = repr("config_settings"),
+        platform_constraint_values = render.dict(
+            platform_constraint_values,
+            value_repr = render.list,
+        ),
         **_repr_dict(value_repr = render.list, **kwargs)
     ))
 

tests/pypi/extension/extension_tests.bzl

@@ -1063,6 +1063,10 @@ def _test_pipstar_platforms(env):
                 default = [
                     _default(
                         platform = "{}_{}".format(os, cpu),
+                        constraint_values = [
+                            "@platforms//os:{}".format(os),
+                            "@platforms//cpu:{}".format(cpu),
+                        ],
                     )
                     for os, cpu in [
                         ("linux", "x86_64"),