simplify markers fully in _compact_markers

Exploit the same cnf / dnf trick that is used in marker union

src/poetry/core/version/markers.py

@@ -699,18 +699,21 @@ def parse_marker(marker: str) -> BaseMarker:
 def _compact_markers(tree_elements: Tree, tree_prefix: str = "") -> BaseMarker:
     from lark import Token
 
-    groups: list[BaseMarker] = [MultiMarker()]
+    # groups is a disjunction of conjunctions
+    # eg [[A, B], [C, D]] represents "(A and B) or (C and D)"
+    groups: list[list[BaseMarker]] = [[]]
+
     for token in tree_elements:
         if isinstance(token, Token):
             if token.type == f"{tree_prefix}BOOL_OP" and token.value == "or":
-                groups.append(MultiMarker())
+                groups.append([])
 
             continue
 
         if token.data == "marker":
-            groups[-1] = MultiMarker.of(
-                groups[-1], _compact_markers(token.children, tree_prefix=tree_prefix)
-            )
+            sub_marker = _compact_markers(token.children, tree_prefix=tree_prefix)
+            groups[-1].append(sub_marker)
+
         elif token.data == f"{tree_prefix}item":
             name, op, value = token.children
             if value.type == f"{tree_prefix}MARKER_NAME":
@@ -720,27 +723,21 @@ def _compact_markers(tree_elements: Tree, tree_prefix: str = "") -> BaseMarker:
                 )
 
             value = value[1:-1]
-            groups[-1] = MultiMarker.of(
-                groups[-1], SingleMarker(str(name), f"{op}{value}")
-            )
-        elif token.data == f"{tree_prefix}BOOL_OP" and token.children[0] == "or":
-            groups.append(MultiMarker())
+            sub_marker = SingleMarker(str(name), f"{op}{value}")
+            groups[-1].append(sub_marker)
 
-    for i, group in enumerate(reversed(groups)):
-        if group.is_empty():
-            del groups[len(groups) - 1 - i]
-            continue
-
-        if isinstance(group, MultiMarker) and len(group.markers) == 1:
-            groups[len(groups) - 1 - i] = group.markers[0]
+        elif token.data == f"{tree_prefix}BOOL_OP" and token.children[0] == "or":
+            groups.append([])
 
-    if not groups:
-        return EmptyMarker()
+    # Combine and simplify the groups.
+    sub_markers = [MultiMarker(*group) for group in groups]
+    union = MarkerUnion(*sub_markers)
 
-    if len(groups) == 1:
-        return groups[0]
+    conjunction = cnf(union)
+    if not isinstance(conjunction, MultiMarker):
+        return conjunction
 
-    return MarkerUnion.of(*groups)
+    return dnf(conjunction)
 
 
 def cnf(marker: BaseMarker) -> BaseMarker:

tests/packages/test_main.py

@@ -102,9 +102,9 @@ def test_dependency_from_pep_508_complex() -> None:
     assert dep.python_versions == ">=2.7 !=3.2.*"
     assert (
         str(dep.marker)
-        == 'python_version >= "2.7" and python_version != "3.2" '
-        'and (sys_platform == "win32" or sys_platform == "darwin") '
-        'and extra == "foo"'
+        == 'python_version >= "2.7" and python_version != "3.2" and sys_platform =='
+        ' "win32" and extra == "foo" or python_version >= "2.7" and python_version'
+        ' != "3.2" and sys_platform == "darwin" and extra == "foo"'
     )
 
 
@@ -278,11 +278,11 @@ def test_dependency_from_pep_508_with_python_full_version() -> None:
     assert dep.name == "requests"
     assert str(dep.constraint) == "2.18.0"
     assert dep.extras == frozenset()
-    assert dep.python_versions == ">=2.7 <2.8 || >=3.4 <3.5.4"
+    assert dep.python_versions == ">=2.7 <2.8 || >=3.4.0 <3.5.4"
     assert (
         str(dep.marker)
         == 'python_version >= "2.7" and python_version < "2.8" '
-        'or python_full_version >= "3.4" and python_full_version < "3.5.4"'
+        'or python_full_version >= "3.4.0" and python_full_version < "3.5.4"'
     )
 
 

tests/packages/utils/test_utils.py

@@ -25,8 +25,8 @@
             {
                 "python_version": [
                     [("<", "3.6")],
-                    [("<", "3.6"), (">=", "3.3")],
                     [("<", "3.3")],
+                    [("<", "3.6"), (">=", "3.3")],
                 ],
                 "sys_platform": [
                     [("==", "win32")],
@@ -41,10 +41,7 @@
                 ' "win32" and python_version < "3.6" and python_version >= "3.3" or'
                 ' sys_platform == "win32" and python_version < "3.3"'
             ),
-            {
-                "python_version": [[("<", "3.6")], [("<", "3.3")]],
-                "sys_platform": [[("==", "win32")]],
-            },
+            {"python_version": [[("<", "3.6")]], "sys_platform": [[("==", "win32")]]},
         ),
         (
             'python_version == "2.7" or python_version == "2.6"',