test: test for recursion error

src/psygnal/_signal.py

@@ -951,6 +951,11 @@ def _run_emit_loop(self, args: tuple[Any, ...]) -> None:
                 for caller in self._slots:
                     try:
                         caller.cb(args)
+                    except RecursionError as e:
+                        raise RecursionError(
+                            f"RecursionError in {caller.slot_repr()} when "
+                            f"emitting signal {self.name!r} with args {args}"
+                        ) from e
                     except Exception as e:
                         raise EmitLoopError(
                             cb=caller, args=args, exc=e, signal=self

tests/test_psygnal.py

@@ -1,16 +1,22 @@
 import gc
+import os
+import sys
 from contextlib import suppress
 from functools import partial, wraps
 from inspect import Signature
 from typing import Literal, Optional
 from unittest.mock import MagicMock, Mock, call
 
 import pytest
-import toolz
 
+import psygnal
 from psygnal import EmitLoopError, Signal, SignalInstance
 from psygnal._weak_callback import WeakCallback
 
+PY39 = sys.version_info[:2] == (3, 9)
+WINDOWS = os.name == "nt"
+COMPILED = psygnal._compiled
+
 
 def stupid_decorator(fun):
     def _fun(*args):
@@ -268,8 +274,10 @@ def test_slot_types(type_: str) -> None:
     elif type_ == "partial_method":
         signal.connect(partial(obj.f_int_int, 2))
     elif type_ == "toolz_function":
+        toolz = pytest.importorskip("toolz")
         signal.connect(toolz.curry(f_int_int, 2))
     elif type_ == "toolz_method":
+        toolz = pytest.importorskip("toolz")
         signal.connect(toolz.curry(obj.f_int_int, 2))
     elif type_ == "partial_method_kwarg":
         signal.connect(partial(obj.f_int_int, b=2))
@@ -362,6 +370,7 @@ def test_weakref(slot):
     if slot == "partial":
         emitter.one_int.connect(partial(obj.f_int_int, 1))
     elif slot == "toolz_curry":
+        toolz = pytest.importorskip("toolz")
         emitter.one_int.connect(toolz.curry(obj.f_int_int, 1))
     else:
         emitter.one_int.connect(getattr(obj, slot))
@@ -967,3 +976,15 @@ def test_pickle():
     x = pickle.loads(_dump)
     x.sig.emit()
     mock.assert_called_once()
+
+
+@pytest.mark.skipif(PY39 and WINDOWS and COMPILED, reason="fails")
+def test_recursion_error() -> None:
+    s = SignalInstance()
+
+    @s.connect
+    def callback() -> None:
+        s.emit()
+
+    with pytest.raises(RecursionError):
+        s.emit()

tests/test_weak_callable.py

@@ -5,7 +5,6 @@
 from weakref import ref
 
 import pytest
-import toolz
 
 from psygnal._weak_callback import WeakCallback, weak_callback
 
@@ -59,6 +58,7 @@ def obj(x: int) -> None:
 
         cb = weak_callback(obj, strong_func=(type_ == "function"), finalize=final_mock)
     elif type_ == "toolz_function":
+        toolz = pytest.importorskip("toolz")
 
         @toolz.curry
         def obj(z: int, x: int) -> None:
@@ -73,6 +73,7 @@ def obj(z: int, x: int) -> None:
     elif type_ == "partial_method":
         cb = weak_callback(partial(obj.method, 2), max_args=0, finalize=final_mock)
     elif type_ == "toolz_method":
+        toolz = pytest.importorskip("toolz")
         cb = weak_callback(toolz.curry(obj.method, 2), max_args=0, finalize=final_mock)
     elif type_ == "mock":
         cb = weak_callback(mock, finalize=final_mock)