refactor: consolidate version parsing (bazel-contrib#2874)

This PR removes all of the custom version parsing functions where we try
to make sense about the version (e.g. extracting major/minor versions).

Whilst doing this I actually think that I made it easier to support
bazel-contrib#2837.

Author: aignas

python/private/BUILD.bazel

@@ -139,7 +139,7 @@ bzl_library(
     name = "config_settings_bzl",
     srcs = ["config_settings.bzl"],
     deps = [
-        ":semver_bzl",
+        ":version_bzl",
         "@bazel_skylib//lib:selects",
         "@bazel_skylib//rules:common_settings",
     ],
@@ -249,9 +249,9 @@ bzl_library(
         ":python_register_toolchains_bzl",
         ":pythons_hub_bzl",
         ":repo_utils_bzl",
-        ":semver_bzl",
         ":toolchains_repo_bzl",
         ":util_bzl",
+        ":version_bzl",
         "@bazel_features//:features",
     ],
 )
@@ -610,11 +610,6 @@ bzl_library(
     ],
 )
 
-bzl_library(
-    name = "semver_bzl",
-    srcs = ["semver.bzl"],
-)
-
 bzl_library(
     name = "sentinel_bzl",
     srcs = ["sentinel.bzl"],

python/private/config_settings.bzl

@@ -18,7 +18,7 @@
 load("@bazel_skylib//lib:selects.bzl", "selects")
 load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load("//python/private:text_util.bzl", "render")
-load(":semver.bzl", "semver")
+load(":version.bzl", "version")
 
 _PYTHON_VERSION_FLAG = Label("//python/config_settings:python_version")
 _PYTHON_VERSION_MAJOR_MINOR_FLAG = Label("//python/config_settings:python_version_major_minor")
@@ -181,8 +181,8 @@ _python_version_flag = rule(
 def _python_version_major_minor_flag_impl(ctx):
     input = _flag_value(ctx.attr._python_version_flag)
     if input:
-        version = semver(input)
-        value = "{}.{}".format(version.major, version.minor)
+        ver = version.parse(input)
+        value = "{}.{}".format(ver.release[0], ver.release[1])
     else:
         value = ""
 

python/private/hermetic_runtime_repo_setup.bzl

@@ -20,7 +20,7 @@ load("//python:py_runtime_pair.bzl", "py_runtime_pair")
 load("//python/cc:py_cc_toolchain.bzl", "py_cc_toolchain")
 load(":glob_excludes.bzl", "glob_excludes")
 load(":py_exec_tools_toolchain.bzl", "py_exec_tools_toolchain")
-load(":semver.bzl", "semver")
+load(":version.bzl", "version")
 
 _IS_FREETHREADED = Label("//python/config_settings:is_py_freethreaded")
 
@@ -53,8 +53,11 @@ def define_hermetic_runtime_toolchain_impl(
             use.
     """
     _ = name  # @unused
-    version_info = semver(python_version)
-    version_dict = version_info.to_dict()
+    version_info = version.parse(python_version)
+    version_dict = {
+        "major": version_info.release[0],
+        "minor": version_info.release[1],
+    }
     native.filegroup(
         name = "files",
         srcs = native.glob(
@@ -198,9 +201,9 @@ def define_hermetic_runtime_toolchain_impl(
         files = [":files"],
         interpreter = python_bin,
         interpreter_version_info = {
-            "major": str(version_info.major),
-            "micro": str(version_info.patch),
-            "minor": str(version_info.minor),
+            "major": str(version_info.release[0]),
+            "micro": str(version_info.release[2]),
+            "minor": str(version_info.release[1]),
         },
         coverage_tool = select({
             # Convert empty string to None

python/private/pypi/BUILD.bazel

@@ -116,7 +116,7 @@ bzl_library(
         ":whl_target_platforms_bzl",
         "//python/private:full_version_bzl",
         "//python/private:normalize_name_bzl",
-        "//python/private:semver_bzl",
+        "//python/private:version_bzl",
         "//python/private:version_label_bzl",
         "@bazel_features//:features",
         "@pythons_hub//:interpreters_bzl",
@@ -256,7 +256,7 @@ bzl_library(
     srcs = ["pep508_evaluate.bzl"],
     deps = [
         "//python/private:enum_bzl",
-        "//python/private:semver_bzl",
+        "//python/private:version_bzl",
     ],
 )
 

python/private/pypi/extension.bzl

@@ -22,7 +22,7 @@ load("//python/private:auth.bzl", "AUTH_ATTRS")
 load("//python/private:full_version.bzl", "full_version")
 load("//python/private:normalize_name.bzl", "normalize_name")
 load("//python/private:repo_utils.bzl", "repo_utils")
-load("//python/private:semver.bzl", "semver")
+load("//python/private:version.bzl", "version")
 load("//python/private:version_label.bzl", "version_label")
 load(":attrs.bzl", "use_isolated")
 load(":evaluate_markers.bzl", "evaluate_markers_py", EVALUATE_MARKERS_SRCS = "SRCS")
@@ -36,9 +36,9 @@ load(":whl_config_setting.bzl", "whl_config_setting")
 load(":whl_library.bzl", "whl_library")
 load(":whl_repo_name.bzl", "pypi_repo_name", "whl_repo_name")
 
-def _major_minor_version(version):
-    version = semver(version)
-    return "{}.{}".format(version.major, version.minor)
+def _major_minor_version(version_str):
+    ver = version.parse(version_str)
+    return "{}.{}".format(ver.release[0], ver.release[1])
 
 def _whl_mods_impl(whl_mods_dict):
     """Implementation of the pip.whl_mods tag class.

python/private/python.bzl

@@ -21,9 +21,9 @@ load(":full_version.bzl", "full_version")
 load(":python_register_toolchains.bzl", "python_register_toolchains")
 load(":pythons_hub.bzl", "hub_repo")
 load(":repo_utils.bzl", "repo_utils")
-load(":semver.bzl", "semver")
 load(":toolchains_repo.bzl", "multi_toolchain_aliases")
 load(":util.bzl", "IS_BAZEL_6_4_OR_HIGHER")
+load(":version.bzl", "version")
 
 def parse_modules(*, module_ctx, _fail = fail):
     """Parse the modules and return a struct for registrations.
@@ -458,16 +458,20 @@ def _fail_multiple_default_toolchains(first, second):
         second = second,
     ))
 
-def _validate_version(*, version, _fail = fail):
-    parsed = semver(version)
-    if parsed.patch == None or parsed.build or parsed.pre_release:
-        _fail("The 'python_version' attribute needs to specify an 'X.Y.Z' semver-compatible version, got: '{}'".format(version))
+def _validate_version(version_str, *, _fail = fail):
+    v = version.parse(version_str, strict = True, _fail = _fail)
+    if v == None:
+        # Only reachable in tests
+        return False
+
+    if len(v.release) < 3:
+        _fail("The 'python_version' attribute needs to specify the full version in at least 'X.Y.Z' format, got: '{}'".format(v.string))
         return False
 
     return True
 
 def _process_single_version_overrides(*, tag, _fail = fail, default):
-    if not _validate_version(version = tag.python_version, _fail = _fail):
+    if not _validate_version(tag.python_version, _fail = _fail):
         return
 
     available_versions = default["tool_versions"]
@@ -517,7 +521,7 @@ def _process_single_version_overrides(*, tag, _fail = fail, default):
         kwargs.setdefault(tag.python_version, {})["distutils"] = tag.distutils
 
 def _process_single_version_platform_overrides(*, tag, _fail = fail, default):
-    if not _validate_version(version = tag.python_version, _fail = _fail):
+    if not _validate_version(tag.python_version, _fail = _fail):
         return
 
     available_versions = default["tool_versions"]
@@ -558,12 +562,12 @@ def _process_global_overrides(*, tag, default, _fail = fail):
 
     if tag.minor_mapping:
         for minor_version, full_version in tag.minor_mapping.items():
-            parsed = semver(minor_version)
-            if parsed.patch != None or parsed.build or parsed.pre_release:
-                fail("Expected the key to be of `X.Y` format but got `{}`".format(minor_version))
-            parsed = semver(full_version)
-            if parsed.patch == None:
-                fail("Expected the value to at least be of `X.Y.Z` format but got `{}`".format(minor_version))
+            parsed = version.parse(minor_version, strict = True, _fail = _fail)
+            if len(parsed.release) > 2 or parsed.pre or parsed.post or parsed.dev or parsed.local:
+                fail("Expected the key to be of `X.Y` format but got `{}`".format(parsed.string))
+
+            # Ensure that the version is valid
+            version.parse(full_version, strict = True, _fail = _fail)
 
         default["minor_mapping"] = tag.minor_mapping
 
@@ -651,8 +655,11 @@ def _get_toolchain_config(*, modules, _fail = fail):
 
     versions = {}
     for version_string in available_versions:
-        v = semver(version_string)
-        versions.setdefault("{}.{}".format(v.major, v.minor), []).append((int(v.patch), version_string))
+        v = version.parse(version_string, strict = True)
+        versions.setdefault(
+            "{}.{}".format(v.release[0], v.release[1]),
+            [],
+        ).append((version.key(v), v.string))
 
     minor_mapping = {
         major_minor: max(subset)[1]

python/private/semver.bzl

@@ -510,7 +510,7 @@ def normalize_pep440(version):
     """
     return _parse(version, strict = True)["norm"]
 
-def _parse(version_str, strict = True):
+def _parse(version_str, strict = True, _fail = fail):
     """Escape the version component of a filename.
 
     See https://packaging.python.org/en/latest/specifications/binary-distribution-format/#escaping-and-unicode
@@ -519,6 +519,7 @@ def _parse(version_str, strict = True):
     Args:
       version_str: version string to be normalized according to PEP 440.
       strict: fail if the version is invalid, defaults to True.
+      _fail: Used for tests
 
     Returns:
       string containing the normalized version.
@@ -544,7 +545,7 @@ def _parse(version_str, strict = True):
     parser_ctx = parser.context()
     if parser.input[parser_ctx["start"]:]:
         if strict:
-            fail(
+            _fail(
                 "Failed to parse PEP 440 version identifier '%s'." % parser.input,
                 "Parse error at '%s'" % parser.input[parser_ctx["start"]:],
             )
@@ -554,7 +555,7 @@ def _parse(version_str, strict = True):
     parser_ctx["is_prefix"] = is_prefix
     return parser_ctx
 
-def parse(version_str, strict = False):
+def parse(version_str, strict = False, _fail = fail):
     """Parse a PEP4408 compliant version.
 
     This is similar to `normalize_pep440`, but it parses individual components to
@@ -563,6 +564,7 @@ def parse(version_str, strict = False):
     Args:
       version_str: version string to be normalized according to PEP 440.
       strict: fail if the version is invalid.
+      _fail: used for tests
 
     Returns:
       a struct with individual components of a version:
@@ -580,29 +582,29 @@ def parse(version_str, strict = False):
         * `string` {type}`str` normalized value of the input.
     """
 
-    parts = _parse(version_str, strict = strict)
+    parts = _parse(version_str, strict = strict, _fail = _fail)
     if not parts:
         return None
 
     if parts["is_prefix"] and (parts["local"] or parts["post"] or parts["dev"] or parts["pre"]):
         if strict:
-            fail("local version part has been obtained, but only public segments can have prefix matches")
+            _fail("local version part has been obtained, but only public segments can have prefix matches")
 
         # https://peps.python.org/pep-0440/#public-version-identifiers
         return None
 
     return struct(
-        epoch = _parse_epoch(parts["epoch"]),
+        epoch = _parse_epoch(parts["epoch"], _fail),
         release = _parse_release(parts["release"]),
         pre = _parse_pre(parts["pre"]),
-        post = _parse_post(parts["post"]),
-        dev = _parse_dev(parts["dev"]),
-        local = _parse_local(parts["local"]),
+        post = _parse_post(parts["post"], _fail),
+        dev = _parse_dev(parts["dev"], _fail),
+        local = _parse_local(parts["local"], _fail),
         string = parts["norm"],
         is_prefix = parts["is_prefix"],
     )
 
-def _parse_epoch(value):
+def _parse_epoch(value, fail):
     if not value:
         return 0
 
@@ -614,7 +616,7 @@ def _parse_epoch(value):
 def _parse_release(value):
     return tuple([int(d) for d in value.split(".")])
 
-def _parse_local(value):
+def _parse_local(value, fail):
     if not value:
         return None
 
@@ -624,7 +626,7 @@ def _parse_local(value):
     # If the part is numerical, handle it as a number
     return tuple([int(part) if part.isdigit() else part for part in value[1:].split(".")])
 
-def _parse_dev(value):
+def _parse_dev(value, fail):
     if not value:
         return None
 
@@ -646,7 +648,7 @@ def _parse_pre(value):
 
     return (prefix, int(value[len(prefix):]))
 
-def _parse_post(value):
+def _parse_post(value, fail):
     if not value:
         return None