Issue #4806: Avoid masking TypeError when *-unpacking a generator
Based on patch by Hagen Fürstenau.
diff --git a/Lib/test/test_extcall.py b/Lib/test/test_extcall.py
index 80e09a0..babcce9 100644
--- a/Lib/test/test_extcall.py
+++ b/Lib/test/test_extcall.py
@@ -93,7 +93,7 @@
>>> g(*Nothing())
Traceback (most recent call last):
...
- TypeError: g() argument after * must be a sequence, not instance
+ TypeError: g() argument after * must be an iterable, not instance
>>> class Nothing:
... def __len__(self): return 5
@@ -102,7 +102,7 @@
>>> g(*Nothing())
Traceback (most recent call last):
...
- TypeError: g() argument after * must be a sequence, not instance
+ TypeError: g() argument after * must be an iterable, not instance
>>> class Nothing():
... def __len__(self): return 5
@@ -128,6 +128,17 @@
>>> g(*Nothing())
0 (1, 2, 3) {}
+Check for issue #4806: Does a TypeError in a generator get propagated with the
+right error message?
+
+ >>> def broken(): raise TypeError("myerror")
+ ...
+
+ >>> g(*(broken() for i in range(1)))
+ Traceback (most recent call last):
+ ...
+ TypeError: myerror
+
Make sure that the function doesn't stomp the dictionary
>>> d = {'a': 1, 'b': 2, 'c': 3}
@@ -167,17 +178,17 @@
>>> h(*h)
Traceback (most recent call last):
...
- TypeError: h() argument after * must be a sequence, not function
+ TypeError: h() argument after * must be an iterable, not function
>>> dir(*h)
Traceback (most recent call last):
...
- TypeError: dir() argument after * must be a sequence, not function
+ TypeError: dir() argument after * must be an iterable, not function
>>> None(*h)
Traceback (most recent call last):
...
- TypeError: NoneType object argument after * must be a sequence, \
+ TypeError: NoneType object argument after * must be an iterable, \
not function
>>> h(**h)
diff --git a/Misc/NEWS b/Misc/NEWS
index 6a80a28..f02087f 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,10 @@
Core and Builtins
-----------------
+- Issue #4806: Avoid masking the original TypeError exception when using star
+ (*) unpacking and the exception was raised from a generator. Based on
+ patch by Hagen Fürstenau.
+
- Issue #26659: Make the builtin slice type support cycle collection.
- Issue #26718: super.__init__ no longer leaks memory if called multiple times.
diff --git a/Python/ceval.c b/Python/ceval.c
index 6e5e272..0b747d8 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4615,10 +4615,12 @@
PyObject *t = NULL;
t = PySequence_Tuple(stararg);
if (t == NULL) {
- if (PyErr_ExceptionMatches(PyExc_TypeError)) {
+ if (PyErr_ExceptionMatches(PyExc_TypeError) &&
+ /* Don't mask TypeError raised from a generator */
+ !PyGen_Check(stararg)) {
PyErr_Format(PyExc_TypeError,
"%.200s%.200s argument after * "
- "must be a sequence, not %200s",
+ "must be an iterable, not %200s",
PyEval_GetFuncName(func),
PyEval_GetFuncDesc(func),
stararg->ob_type->tp_name);