move the implementation for the compatible version matcher

Author: aignas

python/private/py_wheel_normalize_pep440.bzl

@@ -620,6 +620,14 @@ def _version_le(left, right):
     _right = right.key(local = False)
     return _left < _right or _version_eq(left, right)
 
+def _version_compatible(left, right):
+    # https://peps.python.org/pep-0440/#compatible-release
+    # Note, the ~= operator can be also expressed as:
+    # >= V.N, == V.*
+    head, _, _ = right.norm.partition(".")
+    right_star = parse_version("{}.*".format(head))
+    return left.ge(right) and left.eq(right_star)
+
 def _first_non_none(*args):
     for arg in args:
         if arg != None:
@@ -714,6 +722,7 @@ def _new_version(*, epoch = 0, release, pre = "", post = "", dev = "", local = "
         gt = lambda x: _version_gt(self, x),  # buildifier: disable=uninitialized
         le = lambda x: _version_le(self, x),  # buildifier: disable=uninitialized
         ge = lambda x: _version_ge(self, x),  # buildifier: disable=uninitialized
+        compatible = lambda x: _version_compatible(self, x),  # buildifier: disable=uninitialized
         str = lambda: norm,
         key = lambda *, local = True: _key(self, local = local),  # buildifier: disable=uninitialized
     )

python/private/pypi/pep508_evaluate.bzl

@@ -388,12 +388,7 @@ def _version_expr(left, op, right):
     elif op == ">=":
         return _left.ge(_right)
     elif op == "~=":
-        # https://peps.python.org/pep-0440/#compatible-release
-        # Note, the ~= operator can be also expressed as:
-        # >= V.N, == V.*
-        head, _, _ = right.partition(".")
-        _right_star = parse_version("{}.*".format(head))
-        return _left.ge(_right) and _left.eq(_right_star)
+        return _left.compatible(_right)
     else:
         return False  # Let's just ignore the invalid ops
 

tests/pypi/pep508/evaluate_tests.bzl

@@ -297,6 +297,13 @@ _MISC_EXPRESSIONS = [
     _expr_case('python_version <= "1.7.2"', True, {"python_version": "1.7.1"}),
     _expr_case('python_version >= "1.7.1"', True, {"python_version": "1.7.1"}),
     _expr_case('python_version >= "1.7.0"', True, {"python_version": "1.7.1"}),
+    # Compatible version tests:
+    # https://packaging.python.org/en/latest/specifications/version-specifiers/#compatible-release
+    _expr_case('python_version ~= "2.2"', True, {"python_version": "2.3"}),
+    _expr_case('python_version ~= "2.2"', False, {"python_version": "2.1"}),
+    _expr_case('python_version ~= "2.2.post3"', False, {"python_version": "2.2"}),
+    _expr_case('python_version ~= "2.2.post3"', True, {"python_version": "2.3"}),
+    _expr_case('python_version ~= "2.2.post3"', False, {"python_version": "3.0"}),
 ]
 
 def _misc_expressions(env):