Make einfo compatible with inspect (fixes #176)

Author: mrcljx

billiard/einfo.py

@@ -1,5 +1,6 @@
 import sys
 import traceback
+import types
 
 __all__ = ['ExceptionInfo', 'Traceback']
 
@@ -26,6 +27,10 @@ def __init__(self, code):
             self.co_qualname = code.co_qualname
             self._co_positions = list(code.co_positions())
 
+    @property
+    def __class__(self):
+        return types.CodeType
+
     if sys.version_info >= (3, 11):
         @property
         def co_positions(self):
@@ -58,6 +63,10 @@ def __init__(self, frame):
         # don't want to hit https://bugs.python.org/issue21967
         self.f_restricted = False
 
+    @property
+    def __class__(self):
+        return types.FrameType
+
     if sys.version_info >= (3, 11):
         @property
         def co_positions(self):
@@ -100,6 +109,10 @@ def __init__(self):
         self.tb_next = None
         self.tb_lasti = 0
 
+    @property
+    def __class__(self):
+        return types.TracebackType
+
     if sys.version_info >= (3, 11):
         @property
         def co_positions(self):
@@ -120,6 +133,10 @@ def __init__(self, tb, max_frames=DEFAULT_MAX_FRAMES, depth=0):
             else:
                 self.tb_next = _Truncated()
 
+    @property
+    def __class__(self):
+        return types.TracebackType
+
 
 class RemoteTraceback(Exception):
     def __init__(self, tb):

t/unit/test_einfo.py

@@ -1,6 +1,8 @@
+import inspect
 import logging
 import pickle
 import sys
+import types
 
 from billiard.einfo import _Code  # noqa
 from billiard.einfo import _Frame  # noqa
@@ -116,3 +118,34 @@ def test_truncated_co_positions():
         assert list(iter(truncated.co_positions())) == list(
             iter(truncated.tb_frame.co_positions())
         )
+def make_python_tb():
+    tb = None
+    depth = 0
+    while True:
+        try:
+            frame = sys._getframe(depth)
+        except ValueError:
+            break
+        else:
+            depth += 1
+
+        tb = types.TracebackType(tb, frame, frame.f_lasti, frame.f_lineno)
+
+    return tb
+
+
+class test_inspect:
+    def test_istraceback(self):
+        assert inspect.istraceback(Traceback(tb=make_python_tb()))
+
+    def test_isframe(self):
+        assert inspect.isframe(_Frame(make_python_tb().tb_frame))
+
+    def test_iscode(self):
+        assert inspect.iscode(_Code(make_python_tb().tb_frame.f_code))
+
+    def test_getframeinfo(self):
+        assert inspect.getframeinfo(Traceback(tb=make_python_tb()))
+
+    def test_getinnerframes(self):
+        assert inspect.getinnerframes(Traceback(tb=make_python_tb()))