Message176102
| Author |
alexis.d |
| Recipients |
alexis.d, benjamin.peterson, christian.heimes, jcea, lemburg |
| Date |
2012年11月22日.09:26:29 |
| SpamBayes Score |
-1.0 |
| Marked as misclassified |
Yes |
| Message-id |
<1353576389.89.0.259129969651.issue16527@psf.upfronthosting.co.za> |
| In-reply-to |
| Content |
I don't think it can be "fixed" with sys.setrecursionlimit for a few reasons:
* I think the issue arises when the AST is built. Otherwise if we put code before the if it would execute. But that's not the case (try putting a print('hello') before the if and it won't print anything).
- This also means that you cannot directly call sys.setrecursionlimit in the file with the elifs.
- Though we can set recursion limit using a second file which will then import the elifs file: I tried with different limits and CPython still crash in the same way (and always with the same number of elifs, roughly, because I didn't binary search for the exact amount of elifs).
- sys.setrecursionlimit controls the stack size of the running Python program, while here we break C stack directly before running Python bytecode.
* When recursion limit is hit, an exception is raised, there's no segfault:
>>> def f():
... f()
...
>>> f()
# plenty of omitted lines
RuntimeError: maximum recursion depth exceeded
>>>
* Having a RuntimeError raised would be nice, though 'maximum recursion depth exceeded' may not be the best possible error message as from a 'Python user' POV there's no recursion here.
---
A possible solution would be, I guess, to store elifs as excepts are stored. Instead of storing elifs recursively, the else part would just contain a list of if nodes (and if there is a else, well just store an if True node).
Though I don't know how difficult it would be to implement that, or if it's likely to break a lot of things which relies on ifs/elifs to be stored that way. |
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