Support and test internal fields on Python up to 3.12

.github/workflows/pythonapp.yml

@@ -6,7 +6,7 @@ jobs:
   build:
     strategy:
       matrix:
-        python: [ '3.7', '3.8', '3.9', '3.10', '3.11' ]
+        python: [ '3.7', '3.8', '3.9', '3.10', '3.11', '3.12' ]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3

pylasu/model/model.py

@@ -25,12 +25,17 @@ class InternalField(Field):
 
 
 def internal_field(
-        *, default=MISSING, default_factory=MISSING, init=True, repr=True, hash=None, compare=True, metadata=None):
+        *, default=MISSING, default_factory=MISSING, init=True, repr=True, hash=None, compare=True, metadata=None,
+        kw_only=False):
     """Return an object to identify internal dataclass fields. The arguments are the same as dataclasses.field."""
 
     if default is not MISSING and default_factory is not MISSING:
         raise ValueError('cannot specify both default and default_factory')
-    return InternalField(default, default_factory, init, repr, hash, compare, metadata)
+    try:
+        # Python 3.10+
+        return InternalField(default, default_factory, init, repr, hash, compare, metadata, kw_only)
+    except:
+        return InternalField(default, default_factory, init, repr, hash, compare, metadata)
 
 
 class Origin(ABC):

tests/fixtures.py

@@ -1,13 +1,14 @@
 from dataclasses import dataclass, field
 from typing import List
 
-from pylasu.model import Node, pos
+from pylasu.model import Node, pos, internal_field
 
 
 @dataclass
 class Box(Node):
     name: str = None
     contents: List[Node] = field(default_factory=list)
+    internal: str = internal_field(default="unused")
 
 
 @dataclass