The comment following used to say:
/* We use ~hash instead of hash, as degenerate hash functions, such
as for ints <sigh>, can have lots of leading zeros. It's not
really a performance risk, but better safe than sorry.
12-Dec-00 tim: so ~hash produces lots of leading ones instead --
what's the gain? */
That is, there was never a good reason for doing it. And to the contrary,
as explained on Python-Dev last December, it tended to make the *sum*
(i + incr) & mask (which is the first table index examined in case of
collison) the same "too often" across distinct hashes.
Changing to the simpler "i = hash & mask" reduced the number of string-dict
collisions (== # number of times we go around the lookup for-loop) from about
6 million to 5 million during a full run of the test suite (these are
approximate because the test suite does some random stuff from run to run).
The number of collisions in non-string dicts also decreased, but not as
dramatically.
Note that this may, for a given dict, change the order (wrt previous
releases) of entries exposed by .keys(), .values() and .items(). A number
of std tests suffered bogus failures as a result. For dicts keyed by
small ints, or (less so) by characters, the order is much more likely to be
in increasing order of key now; e.g.,
>>> d = {}
>>> for i in range(10):
... d[i] = i
...
>>> d
{0: 0, 1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9}
>>>
Unfortunately. people may latch on to that in small examples and draw a
bogus conclusion.
test_support.py
Moved test_extcall's sortdict() into test_support, made it stronger,
and imported sortdict into other std tests that needed it.
test_unicode.py
Excluced cp875 from the "roundtrip over range(128)" test, because
cp875 doesn't have a well-defined inverse for unicode("?", "cp875").
See Python-Dev for excruciating details.
Cookie.py
Chaged various output functions to sort dicts before building
strings from them.
test_extcall
Fiddled the expected-result file. This remains sensitive to native
dict ordering, because, e.g., if there are multiple errors in a
keyword-arg dict (and test_extcall sets up many cases like that), the
specific error Python complains about first depends on native dict
ordering.
Fixed a half dozen ways in which general dict comparison could crash
Python (even cause Win98SE to reboot) in the presence of kay and/or
value comparison routines that mutate the dict during dict comparison.
Bugfix candidate.
NEEDS DOC CHANGES.
This one surprised me! While I expected tuple() to be a no-brainer, turns
out it's actually dripping with consequences:
1. It will *allow* the popular PySequence_Fast() to work with any iterable
object (code for that not yet checked in, but should be trivial).
2. It caused two std tests to fail. This because some places used
PyTuple_Sequence() (the C spelling of tuple()) as an indirect way to test
whether something *is* a sequence. But tuple() code only looked for the
existence of sq->item to determine that, and e.g. an instance passed
that test whether or not it supported the other operations tuple()
needed (e.g., __len__). So some things the tests *expected* to fail
with an AttributeError now fail with a TypeError instead. This looks
like an improvement to me; e.g., test_coercion used to produce 559
TypeErrors and 2 AttributeErrors, and now they're all TypeErrors. The
error details are more informative too, because the places calling this
were *looking* for TypeErrors in order to replace the generic tuple()
"not a sequence" msg with their own more specific text, and
AttributeErrors snuck by that.
The new test case demonstrates the bug. Be more careful in
symtable_resolve_free() to add a var to cells or frees only if it
won't be added under some other rule.
XXX Add new assertion that will catch this bug.
of ParserCreate().
Added assignment tests for the ordered_attributes and specified_attributes
values, similar to the checks for the returns_unicode attribute.
The changes cause compilation failures in any file in the Python
installation lib directory to cause the install to fail. It looks
like compileall.py intended to behave this way, but a change to
py_compile.py and a separate bug defeated it.
Fixes SF bug #412436
This change affects the test suite, which contains several files that
contain intentional errors. The solution is to extend compileall.py
with the ability to skip compilation of selected files.
In the test suite, rename nocaret.py and test_future[3..7].py to start
with badsyntax_nocaret.py and badsyntax_future[3..7].py. Update the
makefile to skip compilation of these files. Update the tests to use
the name names for imports.
NB compileall.py is changed so that compile_dir() returns success only
if all recursive calls to compile_dir() also check success.
fixes bug #414940, and redoes the fix for #129417 in a different way.
It also fixes a number of other problems with locale-specific formatting:
If there is leading or trailing spaces, then no grouping should be applied
in the spaces, and the total length of the string should not be changed
due to grouping.
Also added test case which works only if the en_US locale is available.
This makes verbose-mode output easier to dig thru, and removes an accidental
dependence on the order of dict.items() (made visible by recent changes to
dictobject.c).
of another list comp. This caused crashes reported as SF bugs 409230
and 407800.
Note that the new tests are in a function so that the name lookup code
isn't affected by how many *other* list comprehensions are in the same
scope.
Fred Drake
Martin v. Löwis
Jeremy Hylton
Tim Peters
Mark Hammond
Guido van Rossum
Fredrik Lundh
Ka-Ping Yee