[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Jason R. Coombs added the comment: I believe I encountered this issue today on Python 2.7.14 (https://ci.appveyor.com/project/jaraco/jaraco-windows/build/31/job/lenh5l4dcmj137b9). In this case, I have an iterable (in itertools.imap) that raises a TypeError when evaluated,

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by Martin Panter : -- resolution: -> fixed stage: patch review -> resolved status: open -> closed ___ Python tracker ___

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Roundup Robot added the comment: New changeset eef8f72ddb00 by Martin Panter in branch '2.7': Issue #4806: Avoid masking TypeError when *-unpacking a generator https://hg.python.org/cpython/rev/eef8f72ddb00 -- ___ Python tracker

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Michel Desmoulin added the comment: We fixed our bug days ago, but I would have expected [*gen] to have triggered an exception before it even got to gather(). The real code was something like: >>> l = (ensure_awaitable(callable_obj) for callable_obj in callable_list) >>> gather(*l)

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Roundup Robot added the comment: New changeset 1a8dc350962b by Martin Panter in branch '3.5': Issue #4806: Avoid masking original TypeError in call with * unpacking https://hg.python.org/cpython/rev/1a8dc350962b New changeset 1261f5f6fc95 by Martin Panter in branch 'default': Issue #4806: Merge

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Martin Panter added the comment: I think this is ready to push for Python 3. Python 2 might need an extra Py_TPFLAGS_HAVE_ITER check, perhaps reusing some code from the Issue 5218 patch. -- stage: patch review -> commit review versions: +Python 3.6 -Python 3.4

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by STINNER Victor : -- nosy: +yselivanov ___ Python tracker ___ ___

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Samuel BOVÉE added the comment: Up for this bug. I got this bug in my code and loose one hour to understand what happened. Please review Martin's patch ! -- nosy: +Samuel BOVÉE ___ Python tracker

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Martin Panter added the comment: I am posting a new version of Daniel’s patch as issue4806-star-TypeError.v2.patch: * Merged with recent “default” (3.5) branch * Dropped the documentation fix, since revision a8aa918041c2 already fixed that in an identical fashion * Changed to a “look before

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

R. David Murray added the comment: Sounds like we just need someone comfortable with modifying ceval.c to apply this ;) -- nosy: +benjamin.peterson, r.david.murray versions: +Python 3.4, Python 3.5 -Python 3.2, Python 3.3 ___ Python tracker

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by pfctdayelise brianna.laug...@gmail.com: -- nosy: +pfctdayelise ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___ ___

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by Chris Kaynor ckay...@zindagigames.com: -- nosy: +DragonFireCK ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___ ___

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by Jon Brandvein jon.brandv...@gmail.com: -- nosy: +brandj ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___ ___ Python-bugs-list

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Terry J. Reedy tjre...@udel.edu added the comment: #13904 is another dup, with patches to test and ceval. I asked that they be reloaded to this issue. -- nosy: +ncoghlan versions: -Python 3.1 ___ Python tracker rep...@bugs.python.org

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by Terry J. Reedy tjre...@udel.edu: -- nosy: +ron_adam ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___ ___ Python-bugs-list mailing

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Terry J. Reedy tjre...@udel.edu added the comment: #5218 is a 4th duplicate, also with a patch to the ceval loop and test. -- nosy: +georg.brandl, gpolo, pitrou ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Terry J. Reedy tjre...@udel.edu added the comment: Sorry Martin, I see you already said that. Anyway, I closed other three in favor of this one. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by Martin Panter vadmium...@gmail.com: -- nosy: +vadmium ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___ ___ Python-bugs-list

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Martin Panter vadmium...@gmail.com added the comment: I haven’t tried to understand what the patches do, but Issue 5218 looks like a very similar problem with a patch including a test case. -- ___ Python tracker rep...@bugs.python.org

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Terry J. Reedy tjre...@udel.edu added the comment: #11944 is probably a duplicate of this and should be checked when this is fixed -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by Daniel Urban urban.dani...@gmail.com: -- nosy: +durban ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___ ___ Python-bugs-list

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Daniel Urban urban.dani...@gmail.com added the comment: I think the patch isn't entirely correct. It uses PyIter_Check for detecting the case when an *iterable* raises TypeError, but that function actually checks for an *iterator*. The check on the tp_iter member mentioned by Amaury Forgeot

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Daniel Urban urban.dani...@gmail.com added the comment: I'm attaching an updated patch. Instead !PyIter_Check() this patch checks for tp_iter == NULL !PySequence_Check. If this condition is false, PyObject_GetIter has a chance to succeed (and if it fails, we shouldn't mask the exception).

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Hagen Fürstenau hfuerste...@gmx.net added the comment: IIUC, the only change you suggest for my patch is using finite iterable instead of sequence or iterable, right? I've looked at the docs and there seems to be no precedent for finite iterable. I think it's just as obvious that the iterable

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Terry J. Reedy tjre...@udel.edu added the comment: Ok, leave iterable as is. More important, you have two disjoint patches that I believe should be combined. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Hagen Fürstenau hfuerste...@gmx.net added the comment: Attaching a combined patch against the current py3k. -- Added file: http://bugs.python.org/file18404/combined.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Terry J. Reedy tjre...@udel.edu added the comment: I verified with 3.1 the two OP cases and that generators work fine as long as they supply the correct number of values. def f(x): return x def broken(): return 1 print(f(*(broken() for x in (0, # prints 1 Change (0,) to (0,1) the normal

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Bruce Frederiksen dangy...@gmail.com added the comment: I have also hit this error. I went to report it but found it already entered (good news), but not resolved from nearly a year ago (bad news). The error masked another bug that I had in my program and it took me quite awhile to figure

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by Alexander Belopolsky belopol...@users.sourceforge.net: -- keywords: +needs review stage: - patch review ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Hagen Fürstenau hfuerste...@gmx.net added the comment: I added a simple check for iterables. This is not very elegant, but performance is only affected in the case of an exception. Patch and corresponsing test are attached as TypeError.patch. As I pointed out above, the actual error message

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Amaury Forgeot d'Arc amaur...@gmail.com added the comment: This patch leaks a reference on each call to PyObject_GetIter(). And I'm not sure it is a good idea to call this function again: it may be very expensive! I'd prefer a simple check on the tp_iter member. --

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Hagen Fürstenau hfuerste...@gmx.net added the comment: Sorry, I had meant to use PyIter_Check instead of PyObject_GetIter. Don't know why I didn't do so... ;-) I corrected the patch. -- Added file: http://bugs.python.org/file14169/TypeError2.patch

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Changes by Hagen Fürstenau hfuerste...@gmx.net: Removed file: http://bugs.python.org/file14166/TypeError.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4806 ___

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Kenneth Arnold kenneth.arn...@gmail.com added the comment: I can confirm that (a) this exact behavior is happening and (b) it quite confused me (most of the time it works!). What would be a good TypeError? I'd vote for generators to be explicitly supported even if it required a special case.

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Hagen Fürstenau hfuerste...@gmx.net added the comment: I'm getting confused about whether it's actually desired behaviour that generators can be star arguments. The error message seems to say it's not: argument after * must be a sequence. The docs seem to agree: If the syntax *expression

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

New submission from Hagen Fürstenau hfuerste...@gmx.net: If we call some function f with a generator as star argument and this generator raises a TypeError, we get the following exception: def f(x): pass ... def broken(): raise TypeError ... f(*(broken() for x in (0,))) Traceback (most

[issue4806] Function calls taking a generator as star argument can mask TypeErrors in the generator

Amaury Forgeot d'Arc amaur...@gmail.com added the comment: The issue1615 has the same kind of problems: an AttributeError is masked by another one. -- nosy: +amaury.forgeotdarc ___ Python tracker rep...@bugs.python.org