fix(pypi): select the lowest available libc version by default (bazel-contrib#3255)

The bazel-contrib#3058 PR has subtly changed the default behaviour of
`experimental_index_url` code path and I think in order to make things
easier by default for our users we should go back to that behaviour.

And in addition to this we are starting to make use of the Minimal
Version Selection algorithm for the platforms. This in general allows
users to configure the upper platform version for a particular wheel.
This meant that we had to change the semantics of the API a little:
1. Use MVS for each platform platform tag.
2. Make it such that earlier entries are overridden by later ones, i.e.
   `["musllinux_*_x86_64", "musllinux_1_2_x86_64"]` is effectively the
   same as just `["musllinux_1_2_x86_64"]`.

A remaining thing that will be left as a followup for bazel-contrib#2747 will be to
figure out how to allow users to ignore certain platform tags.

Fixes bazel-contrib#3250

---------

Co-authored-by: Richard Levasseur <richardlev@gmail.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: 3 people

CHANGELOG.md

@@ -79,6 +79,13 @@ END_UNRELEASED_TEMPLATE
   length errors due to too long environment variables.
 * (bootstrap) {obj}`--bootstrap_impl=script` now supports the `-S` interpreter
   setting.
+* (pypi) We now use the Minimal Version Selection (MVS) algorithm to select
+  the right wheel when there are multiple wheels for the target platform
+  (e.g. `musllinux_1_1_x86_64` and `musllinux_1_2_x86_64`). If the user
+  wants to set the minimum version for the selection algorithm, use the
+  {attr}`pip.defaults.whl_platform_tags` attribute to configure that. If
+  `musllinux_*_x86_64` is specified, we will chose the lowest available
+  wheel version. Fixes [#3250](https://github.com/bazel-contrib/rules_python/issues/3250).
 
 {#v0-0-0-added}
 ### Added

python/private/pypi/extension.bzl

@@ -492,35 +492,37 @@ preference.
 Will always  include `"any"` even if it is not specified.
 
 The items in this list can contain a single `*` character that is equivalent to matching the
-latest available version component in the platform_tag. Note, if the wheel platform tag does not
-have a version component, e.g. `linux_x86_64` or `win_amd64`, then `*` will act as a regular
-character.
-
-We will always select the highest available `platform_tag` version that is compatible with the
-target platform.
+lowest available version component in the platform_tag. If the wheel platform tag does not
+have a version component, e.g. `linux_x86_64` or `win_amd64`, then `*` will act as a regular character.
 
 :::{note}
+Normally, the `*` in the matcher means that we will target the lowest platform version that we can
+and will give preference to whls built targeting the older versions of the platform. If you
+specify the version, then we will use the MVS (Minimal Version Selection) algorithm to select the
+compatible wheel. As such, you need to keep in mind how to configure the target platforms to
+select a particular wheel of your preference.
+
 We select a single wheel and the last match will take precedence, if the platform_tag that we
 match has a version component (e.g. `android_x_arch`, then the version `x` will be used in the
-matching algorithm).
-
-If the matcher you provide has `*`, then we will match a wheel with the highest available target platform, i.e. if `musllinux_1_1_arch` and `musllinux_1_2_arch` are both present, then we will select `musllinux_1_2_arch`.
-Otherwise we will select the highest available version that is equal or lower to the specifier, i.e. if `manylinux_2_12` and `manylinux_2_17` wheels are present and the matcher is `manylinux_2_15`, then we will match `manylinux_2_12` but not `manylinux_2_17`.
-:::
-
-:::{note}
-The following tag prefixes should be used instead of the legacy equivalents:
-* `manylinux_2_5` instead of `manylinux1`
-* `manylinux_2_12` instead of `manylinux2010`
-* `manylinux_2_17` instead of `manylinux2014`
-
-When parsing the whl filenames `rules_python` will automatically transform wheel filenames to the
-latest format.
+MVS matching algorithm).
+
+Common patterns:
+* To select any versioned wheel for an `<os>`, `<arch>`, use `<os>_*_<arch>`, e.g.
+  `manylinux_2_17_x86_64`.
+* To exclude versions up to `X.Y` - **submit a PR supporting this feature**.
+* To exclude versions above `X.Y`, provide the full platform tag specifier, e.g.
+  `musllinux_1_2_x86_64`, which will ensure that no wheels with `musllinux_1_3_x86_64` or higher
+  are selected.
 :::
 
 :::{seealso}
 See official [docs](https://packaging.python.org/en/latest/specifications/platform-compatibility-tags/#platform-tag) for more information.
 :::
+:::{versionchanged} VERSION_NEXT_FEATURE
+The matching of versioned platforms have been switched to MVS (Minimal Version Selection)
+algorithm for easier evaluation logic and fewer surprises. The legacy platform tags are
+supported from this version without extra handling from the user.
+:::
 """,
     ),
 } | AUTH_ATTRS

python/private/pypi/select_whl.bzl

@@ -10,6 +10,21 @@ _MANYLINUX = "manylinux"
 _MACOSX = "macosx"
 _MUSLLINUX = "musllinux"
 
+# Taken from https://peps.python.org/pep-0600/
+_LEGACY_ALIASES = {
+    "manylinux1_i686": "manylinux_2_5_i686",
+    "manylinux1_x86_64": "manylinux_2_5_x86_64",
+    "manylinux2010_i686": "manylinux_2_12_i686",
+    "manylinux2010_x86_64": "manylinux_2_12_x86_64",
+    "manylinux2014_aarch64": "manylinux_2_17_aarch64",
+    "manylinux2014_armv7l": "manylinux_2_17_armv7l",
+    "manylinux2014_i686": "manylinux_2_17_i686",
+    "manylinux2014_ppc64": "manylinux_2_17_ppc64",
+    "manylinux2014_ppc64le": "manylinux_2_17_ppc64le",
+    "manylinux2014_s390x": "manylinux_2_17_s390x",
+    "manylinux2014_x86_64": "manylinux_2_17_x86_64",
+}
+
 def _value_priority(*, tag, values):
     keys = []
     for priority, wp in enumerate(values):
@@ -18,17 +33,61 @@ def _value_priority(*, tag, values):
 
     return max(keys) if keys else None
 
-def _platform_tag_priority(*, tag, values):
-    # Implements matching platform tag
-    # https://packaging.python.org/en/latest/specifications/platform-compatibility-tags/
-
-    if not (
+def _is_platform_tag_versioned(tag):
+    return (
         tag.startswith(_ANDROID) or
         tag.startswith(_IOS) or
         tag.startswith(_MACOSX) or
         tag.startswith(_MANYLINUX) or
         tag.startswith(_MUSLLINUX)
-    ):
+    )
+
+def _parse_platform_tags(tags):
+    """A helper function that parses all of the platform tags.
+
+    The main idea is to make this more robust and have better debug messages about which will
+    is compatible and which is not with the target platform.
+    """
+    ret = []
+    replacements = {}
+    for tag in tags:
+        tag = _LEGACY_ALIASES.get(tag, tag)
+
+        if not _is_platform_tag_versioned(tag):
+            ret.append(tag)
+            continue
+
+        want_os, sep, tail = tag.partition("_")
+        if not sep:
+            fail("could not parse the tag: {}".format(tag))
+
+        want_major, _, tail = tail.partition("_")
+        if want_major == "*":
+            # the expected match is any version
+            want_arch = tail
+        elif want_os.startswith(_ANDROID):
+            want_arch = tail
+        else:
+            # drop the minor version segment
+            _, _, want_arch = tail.partition("_")
+
+        placeholder = "{}_*_{}".format(want_os, want_arch)
+        replacements[placeholder] = tag
+        if placeholder in ret:
+            ret.remove(placeholder)
+
+        ret.append(placeholder)
+
+    return [
+        replacements.get(p, p)
+        for p in ret
+    ]
+
+def _platform_tag_priority(*, tag, values):
+    # Implements matching platform tag
+    # https://packaging.python.org/en/latest/specifications/platform-compatibility-tags/
+
+    if not _is_platform_tag_versioned(tag):
         res = _value_priority(tag = tag, values = values)
         if res == None:
             return res
@@ -39,7 +98,7 @@ def _platform_tag_priority(*, tag, values):
 
     os, _, tail = tag.partition("_")
     major, _, tail = tail.partition("_")
-    if not os.startswith(_ANDROID):
+    if not tag.startswith(_ANDROID):
         minor, _, arch = tail.partition("_")
     else:
         minor = "0"
@@ -65,7 +124,7 @@ def _platform_tag_priority(*, tag, values):
             want_major = ""
             want_minor = ""
             want_arch = tail
-        elif os.startswith(_ANDROID):
+        elif tag.startswith(_ANDROID):
             # we set it to `0` above, so setting the `want_minor` her to `0` will make things
             # consistent.
             want_minor = "0"
@@ -81,7 +140,7 @@ def _platform_tag_priority(*, tag, values):
         # if want_major is defined, then we know that we don't have a `*` in the matcher.
         want_version = (int(want_major), int(want_minor)) if want_major else None
         if not want_version or version <= want_version:
-            keys.append((priority, version))
+            keys.append((priority, (-version[0], -version[1])))
 
     return max(keys) if keys else None
 
@@ -222,7 +281,7 @@ def select_whl(
         implementation_name = implementation_name,
         python_version = python_version,
         whl_abi_tags = whl_abi_tags,
-        whl_platform_tags = whl_platform_tags,
+        whl_platform_tags = _parse_platform_tags(whl_platform_tags),
         logger = logger,
     )
 

tests/pypi/select_whl/select_whl_tests.bzl

@@ -131,7 +131,6 @@ def _test_not_select_abi3(env):
         whl_abi_tags = ["none"],
         python_version = "3.13",
         limit = 2,
-        debug = True,
     )
     _match(
         env,
@@ -232,6 +231,34 @@ def _test_select_by_supported_cp_version(env):
 
 _tests.append(_test_select_by_supported_cp_version)
 
+def _test_legacy_manylinux(env):
+    for legacy, replacement in {
+        "manylinux1": "manylinux_2_5",
+        "manylinux2010": "manylinux_2_12",
+        "manylinux2014": "manylinux_2_17",
+    }.items():
+        for plat in [legacy, replacement]:
+            whls = [
+                "pkg-0.0.1-py3-none-{}_x86_64.whl".format(plat),
+                "pkg-0.0.1-py3-none-any.whl",
+            ]
+
+            got = _select_whl(
+                whls = whls,
+                whl_platform_tags = ["{}_x86_64".format(legacy)],
+                whl_abi_tags = ["none"],
+                python_version = "3.10",
+            )
+            want = _select_whl(
+                whls = whls,
+                whl_platform_tags = ["{}_x86_64".format(replacement)],
+                whl_abi_tags = ["none"],
+                python_version = "3.10",
+            )
+            _match(env, [got], want.filename)
+
+_tests.append(_test_legacy_manylinux)
+
 def _test_supported_cp_version_manylinux(env):
     whls = [
         "pkg-0.0.1-py2.py3-none-manylinux_1_1_x86_64.whl",
@@ -406,9 +433,10 @@ def _test_multiple_musllinux(env):
     _match(
         env,
         got,
-        # select the one with the highest version that is matching
-        "pkg-0.0.1-py3-none-musllinux_1_1_x86_64.whl",
+        # select the one with the lowest version that is matching because we want to
+        # increase the compatibility
         "pkg-0.0.1-py3-none-musllinux_1_2_x86_64.whl",
+        "pkg-0.0.1-py3-none-musllinux_1_1_x86_64.whl",
     )
 
 _tests.append(_test_multiple_musllinux)
@@ -423,17 +451,85 @@ def _test_multiple_musllinux_exact_params(env):
         whl_abi_tags = ["none"],
         python_version = "3.12",
         limit = 2,
+        debug = True,
     )
     _match(
         env,
         got,
-        # select the one with the lowest version, because of the input to the function
-        "pkg-0.0.1-py3-none-musllinux_1_2_x86_64.whl",
+        # 1.2 is not within the candidates because it is not compatible
         "pkg-0.0.1-py3-none-musllinux_1_1_x86_64.whl",
     )
 
 _tests.append(_test_multiple_musllinux_exact_params)
 
+def _test_multiple_mvs_match(env):
+    got = _select_whl(
+        whls = [
+            "pkg-0.0.1-py3-none-musllinux_1_4_x86_64.whl",
+            "pkg-0.0.1-py3-none-musllinux_1_2_x86_64.whl",
+            "pkg-0.0.1-py3-none-musllinux_1_1_x86_64.whl",
+        ],
+        whl_platform_tags = ["musllinux_1_3_x86_64"],
+        whl_abi_tags = ["none"],
+        python_version = "3.12",
+        limit = 2,
+    )
+    _match(
+        env,
+        got,
+        # select the one with the lowest version
+        "pkg-0.0.1-py3-none-musllinux_1_2_x86_64.whl",
+        "pkg-0.0.1-py3-none-musllinux_1_1_x86_64.whl",
+    )
+
+_tests.append(_test_multiple_mvs_match)
+
+def _test_multiple_mvs_match_override_more_specific(env):
+    got = _select_whl(
+        whls = [
+            "pkg-0.0.1-py3-none-musllinux_1_4_x86_64.whl",
+            "pkg-0.0.1-py3-none-musllinux_1_2_x86_64.whl",
+            "pkg-0.0.1-py3-none-musllinux_1_1_x86_64.whl",
+        ],
+        whl_platform_tags = [
+            "musllinux_*_x86_64",  # default to something
+            "musllinux_1_3_x86_64",  # override the previous
+        ],
+        whl_abi_tags = ["none"],
+        python_version = "3.12",
+        limit = 2,
+    )
+    _match(
+        env,
+        got,
+        # Should be the same as without the `*` match
+        "pkg-0.0.1-py3-none-musllinux_1_2_x86_64.whl",
+        "pkg-0.0.1-py3-none-musllinux_1_1_x86_64.whl",
+    )
+
+_tests.append(_test_multiple_mvs_match_override_more_specific)
+
+def _test_multiple_mvs_match_override_less_specific(env):
+    got = _select_whl(
+        whls = [
+            "pkg-0.0.1-py3-none-musllinux_1_4_x86_64.whl",
+        ],
+        whl_platform_tags = [
+            "musllinux_1_3_x86_64",  # default to 1.3
+            "musllinux_*_x86_64",  # then override to something less specific
+        ],
+        whl_abi_tags = ["none"],
+        python_version = "3.12",
+        limit = 2,
+    )
+    _match(
+        env,
+        got,
+        "pkg-0.0.1-py3-none-musllinux_1_4_x86_64.whl",
+    )
+
+_tests.append(_test_multiple_mvs_match_override_less_specific)
+
 def _test_android(env):
     got = _select_whl(
         whls = [