Deal with a python 3.12 backwards compatibility break with meta_path …

…loaders.

- also add python 3.12 to the testing framework

.github/workflows/python-app.yaml

@@ -13,15 +13,18 @@ jobs:
   tests-py3:
     name: Runs tests
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.9", "3.12"]
 
     steps:
     - uses: actions/checkout@v4
       with:
         submodules: recursive
-    - name: Set up Python 3
+    - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v5
       with:
-        python-version: "3.9"
+        python-version: ${{ matrix.python-version }}
     - name: Test by decompiling a script and building un.rpyc
       run: |
         # test the command line tool

decompiler/magic.py

@@ -29,6 +29,12 @@
 import pickle
 import struct
 
+try:
+    # only available (and needed) from 3.4 onwards.
+    from importlib.machinery import ModuleSpec
+except:
+    pass
+
 if PY3:
     from io import BytesIO as StringIO
 else:
@@ -402,19 +408,36 @@ class FakePackageLoader(object):
     this ensures that any attempt to get a submodule from module *root*
     results in a FakePackage, creating the illusion that *root* is an
     actual package tree.
+
+    This class is both a `finder` and a `loader`
     """
     def __init__(self, root):
         self.root = root
 
+    # the old way of loading modules. find_module returns a loader for the
+    # given module. In this case, that is this object itself again.
+
     def find_module(self, fullname, path=None):
         if fullname == self.root or fullname.startswith(self.root + "."):
             return self
         else:
             return None
 
+    # the new way of loading modules. It returns a ModuleSpec, that has
+    # the loader attribute set to this class.
+
+    def find_spec(self, fullname, path, target=None):
+        if fullname == self.root or fullname.startswith(self.root + "."):
+            return ModuleSpec(fullname, self)
+        else:
+            return None
+
+    # loader methods. This loads the module.
+
     def load_module(self, fullname):
         return FakePackage(fullname)
 
+
 # Fake unpickler implementation
 
 class FakeUnpicklingError(pickle.UnpicklingError):