Issue 25845: _ctypes\cfield.c identical subexpressions in Z_set (original) (raw)
Issue25845
Created on 2015-12-12 04:50 by Alexander Riccio, last changed 2022-04-11 14:58 by admin. This issue is now closed.
| Messages (5) | ||
|---|---|---|
| msg256256 - (view) | Author: Alexander Riccio (Alexander Riccio) * | Date: 2015-12-12 04:50 |
| I found this while writing up a separate bug (CPython doesn't use static analysis!). In _ctypes/cfield.c, Z_set has a bug of some sort: if (PyLong_Check(value) | | PyLong_Check(value)) { See: https://hg.python.org/cpython/file/tip/Modules/_ctypes/cfield.c#l1378 ...which has been there for at least 5 years: https://hg.python.org/cpython/rev/cab14be0ada1 I'm not sure what the original programmer meant - it's been around forever & I don't know what was there before it - but PyLong_Check(value) is evaluated twice. Which doesn't really make sense. Compiling with /analyze found this quite easily: c:\pythondev\repo\modules\_ctypes\cfield.c(1378): warning C6287: Redundant code: the left and right sub-expressions are identical. There's a similar issue in P_set, at line 1486. | |
| msg256261 - (view) | Author: (random832) | Date: 2015-12-12 05:01 |
| Looks like a result of searching and replacing PyInt with PyLong - the diff can be found here, if anyone cares. https://hg.python.org/cpython-fullhistory/rev/f324631462a2. Oddly, there was _another, older_ revision that fixed this correctly: https://hg.python.org/cpython-fullhistory/rev/003d35215ef2 - looks like there was a bad merge somewhere along the line. | ||
| msg256262 - (view) | Author: (random832) | Date: 2015-12-12 05:10 |
| Sorry, my mistake, I was looking at z_set instead of Z_set. The earlier fix had left Z_set out for some reason. Anyway, just some historical interest anyway. | ||
| msg256269 - (view) | Author: Roundup Robot (python-dev)  |
Date: 2015-12-12 07:31 |
| New changeset 26859a7e385c by Martin Panter in branch '3.5': Issue #25845: Drop redundant checks leftover from int to long conversion https://hg.python.org/cpython/rev/26859a7e385c New changeset 9be59ad8af80 by Martin Panter in branch 'default': Issue #25845: Merge PyLong_Check() cleanup from 3.5 https://hg.python.org/cpython/rev/9be59ad8af80 | ||
| msg256271 - (view) | Author: Martin Panter (martin.panter) *  |
Date: 2015-12-12 07:38 |
| History is good for understanding how things became the way they are. :) Thanks Alexander and Random! |
| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:58:24 | admin | set | github: 70032 |
| 2015-12-12 07:38:51 | martin.panter | set | status: open -> closedtype: enhancementversions: + Python 3.5, Python 3.6nosy: + martin.pantermessages: + resolution: fixedstage: resolved |
| 2015-12-12 07:31:25 | python-dev | set | nosy: + python-devmessages: + |
| 2015-12-12 05:10:39 | random832 | set | messages: + |
| 2015-12-12 05:01:37 | random832 | set | nosy: + random832messages: + |
| 2015-12-12 04:50:49 | Alexander Riccio | create |