Fix(ImportManager): Fixed unmarshalling byte-code files

Different Python versions change marshalled byte-code format.

Author: phdru

Cheetah/ImportManager.py

@@ -239,7 +239,21 @@ def getmod(self, nm, getsuffixes=get_suffixes,
                 with open(pyc[0], 'rb') as pyc_file:
                     stuff = pyc_file.read()
                 try:
-                    co = loadco(stuff[8:])
+                    # Different Python versions
+                    # change marshalled byte-code format
+                    if PY2:
+                        offsets = [8]
+                    else:
+                        offsets = [16, 12]
+                    for offset in offsets:
+                        try:
+                            co = loadco(stuff[offset:])
+                        except (ValueError, EOFError):
+                            pass
+                        else:
+                            break
+                    else:
+                        raise
                     __file__ = pyc[0]
                     break
                 except (ValueError, EOFError):

docs/news.rst

@@ -14,6 +14,9 @@ Bug fixes:
   - Use ``cache_from_source`` in ``ImportManager`` to find out
     ``.pyc``/``.pyo`` byte-code files.
 
+  - Fixed unmarshalling ``.pyc``/``.pyo`` byte-code files
+    in ``ImportManager``.
+
   - Fixed ``Template.webInput``: Use ``urllib.parse.parse_qs``
     instead of ``cgi.FieldStorage``; Python 3.13 dropped ``cgi``.