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mark.dickinson
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Issue 705836: Fix struct.pack(">f", 1e40) to behave consistently
across platforms: it should now raise OverflowError on all platforms. (Previously it raised OverflowError only on non IEEE 754 platforms.) Also fix the (already existing) test for this behaviour so that it actually raises TestFailed instead of just referencing it. git-svn-id: http://svn.python.org/projects/python/trunk@61383 6015fed2-1504-0410-9fe1-9d1591cc4771
1 parent 6eedb91 commit c59866a

3 files changed

Lines changed: 13 additions & 9 deletions

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‎Lib/test/test_struct.py‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -482,7 +482,7 @@ def test_705836():
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except OverflowError:
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pass
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else:
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TestFailed("expected OverflowError")
485+
raise TestFailed("expected OverflowError")
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test_705836()
488488

‎Misc/NEWS‎

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Original file line numberDiff line numberDiff line change
@@ -21,6 +21,10 @@ Core and builtins
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Library
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-------
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24+
- Issue #705836: struct.pack(">f", x) now raises OverflowError on all
25+
platforms when x is too large to fit into an IEEE 754 float; previously
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it only raised OverflowError on non IEEE 754 platforms.
27+
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- Issue #1106316: pdb.post_mortem()'s parameter, "traceback", is now
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optional: it defaults to the traceback of the exception that is currently
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being handled (is mandatory to be in the middle of an exception, otherwise

‎Objects/floatobject.c‎

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -1751,9 +1751,6 @@ PyFloat_Fini(void)
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17521752
/*----------------------------------------------------------------------------
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* _PyFloat_{Pack,Unpack}{4,8}. See floatobject.h.
1754-
*
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* TODO: On platforms that use the standard IEEE-754 single and double
1756-
* formats natively, these routines could simply copy the bytes.
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*/
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int
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_PyFloat_Pack4(double x, unsigned char *p, int le)
@@ -1833,28 +1830,31 @@ _PyFloat_Pack4(double x, unsigned char *p, int le)
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/* Done */
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return 0;
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1836-
Overflow:
1837-
PyErr_SetString(PyExc_OverflowError,
1838-
"float too large to pack with f format");
1839-
return -1;
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}
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else {
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float y = (float)x;
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const char *s = (char*)&y;
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int i, incr = 1;
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1839+
if (Py_IS_INFINITY(y) && !Py_IS_INFINITY(x))
1840+
goto Overflow;
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18461842
if ((float_format == ieee_little_endian_format && !le)
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|| (float_format == ieee_big_endian_format && le)) {
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p += 3;
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incr = -1;
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}
1851-
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for (i = 0; i < 4; i++) {
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*p = *s++;
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p += incr;
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}
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return 0;
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}
1854+
Overflow:
1855+
PyErr_SetString(PyExc_OverflowError,
1856+
"float too large to pack with f format");
1857+
return -1;
18581858
}
18591859

18601860
int

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