Fix error with "enqueue=True" and non-picklable exception (#298)

CHANGELOG.rst

@@ -2,7 +2,8 @@
 =============
 
 - Fix ``AttributeError`` within handlers using ``serialize=True`` when calling ``logger.exception()`` outside of the context of an exception (`#296 <https://github.com/Delgan/loguru/issues/296>`_).
-- Add support for async callable classes (with ``__call__`` method) used as sinks (`#294 <https://github.com/Delgan/loguru/issues/294>`_, thanks `@jessekrubin <https://github.com/jessekrubin>`_).
+- Fix error while logging an exception containing a non-picklable ``value`` to a handler with ``enqueue=True`` (`#298 <https://github.com/Delgan/loguru/issues/298>`_).
+- Add support for async callable classes (with ``__call__`` method) used as sinks (`#294 <https://github.com/Delgan/loguru/pull/294>`_, thanks `@jessekrubin <https://github.com/jessekrubin>`_).
 
 
 `0.5.1`_ (2020-06-12)

loguru/_recattrs.py

@@ -1,3 +1,4 @@
+import pickle
 from collections import namedtuple
 
 
@@ -63,5 +64,18 @@ def __repr__(self):
         return "(type=%r, value=%r, traceback=%r)" % (self.type, self.value, self.traceback)
 
     def __reduce__(self):
-        exception = (self.type, self.value, None)  # tracebacks are not pickable
-        return (RecordException, exception)
+        try:
+            pickled_value = pickle.dumps(self.value)
+        except pickle.PickleError:
+            return (RecordException, (self.type, None, None))
+        else:
+            return (RecordException._from_pickled_value, (self.type, pickled_value, None))
+
+    @classmethod
+    def _from_pickled_value(cls, type_, pickled_value, traceback_):
+        try:
+            value = pickle.loads(pickled_value)
+        except pickle.PickleError:
+            return cls(type_, None, traceback_)
+        else:
+            return cls(type_, value, traceback_)

tests/test_add_option_enqueue.py

@@ -3,11 +3,12 @@
 import time
 import re
 import sys
+import pickle
 
 
 class NotPicklable:
     def __getstate__(self):
-        raise RuntimeError("You shall not serialize me!")
+        raise pickle.PicklingError("You shall not serialize me!")
 
     def __setstate__(self, state):
         pass
@@ -18,7 +19,7 @@ def __getstate__(self):
         return "..."
 
     def __setstate__(self, state):
-        raise RuntimeError("You shall not de-serialize me!")
+        raise pickle.UnpicklingError("You shall not de-serialize me!")
 
 
 class NotWritable:
@@ -80,7 +81,7 @@ def test_caught_exception_queue_put(writer, capsys):
     assert out == ""
     assert lines[0] == "--- Logging error in Loguru Handler #0 ---"
     assert re.match(r"Record was: \{.*Bye bye.*\}", lines[1])
-    assert lines[-2] == "RuntimeError: You shall not serialize me!"
+    assert lines[-2].endswith("PicklingError: You shall not serialize me!")
     assert lines[-1] == "--- End of logging error ---"
 
 
@@ -98,7 +99,7 @@ def test_caught_exception_queue_get(writer, capsys):
     assert out == ""
     assert lines[0] == "--- Logging error in Loguru Handler #0 ---"
     assert lines[1] == "Record was: None"
-    assert lines[-2] == "RuntimeError: You shall not de-serialize me!"
+    assert lines[-2].endswith("UnpicklingError: You shall not de-serialize me!")
     assert lines[-1] == "--- End of logging error ---"
 
 
@@ -124,7 +125,7 @@ def test_not_caught_exception_queue_put(writer, capsys):
 
     logger.info("It's fine")
 
-    with pytest.raises(RuntimeError, match=r"You shall not serialize me!"):
+    with pytest.raises(pickle.PicklingError, match=r"You shall not serialize me!"):
         logger.bind(broken=NotPicklable()).info("Bye bye...")
 
     logger.remove()
@@ -149,7 +150,7 @@ def test_not_caught_exception_queue_get(writer, capsys):
     assert writer.read() == "It's fine\n"
     assert out == ""
     assert lines[0].startswith("Exception")
-    assert lines[-1] == "RuntimeError: You shall not de-serialize me!"
+    assert lines[-1].endswith("UnpicklingError: You shall not de-serialize me!")
 
 
 def test_not_caught_exception_sink_write(capsys):
@@ -183,3 +184,26 @@ def slow_sink(message):
 
     assert out == ""
     assert err == "".join("%d\n" % i for i in range(10))
+
+
+@pytest.mark.parametrize("arg", [NotPicklable(), NotUnpicklable()])
+def test_logging_not_picklable_exception(arg):
+    exception = None
+
+    def sink(message):
+        nonlocal exception
+        exception = message.record["exception"]
+
+    logger.add(sink, enqueue=True, catch=False)
+
+    try:
+        raise ValueError(arg)
+    except Exception:
+        logger.exception("Oups")
+
+    logger.remove()
+
+    type_, value, traceback_ = exception
+    assert type_ is ValueError
+    assert value is None
+    assert traceback_ is None

tests/test_coroutine_sink.py

@@ -22,9 +22,6 @@ async def __call__(self, msg):
         print(msg, end="")
 
 
-async_writer_cls = AsyncWriter()
-
-
 def test_coroutine_function(capsys):
     async def worker():
         logger.debug("A message")
@@ -44,7 +41,7 @@ async def worker():
         logger.debug("A message")
         await logger.complete()
 
-    logger.add(async_writer_cls, format="{message}")
+    logger.add(AsyncWriter(), format="{message}")
 
     asyncio.run(worker())