For a long time I've seen absurd tracebacks under -O (e.g., negative
line numbers), but very rarely. Since I was looking at tracebacks
anyway, thought I'd track it down. Turns out to be Guido's only
predictable blind spot <wink -- "char" is signed on some non-GvR
systems>. Patch follows.
tracefunc (or profilefunc -- we're not sure which), zap the global
trace and profile funcs so that we can't get into recursive loop when
instantiating the resulting class based exception.
"""
Following up Robin Dunn's troubles with freeze, here's a patch that
fixes an oddity regarding the import logic of shared modules on AIX.
Symbol resolution of shared modules is now handled properly for the cases
when the python library is linked to a binary with an arbitrary name.
This includes the standard python[version] executable, but also applications
that are embedding the python core (i.e. linked with libpython[version].a,
the latter being static or shared).
"""
Introduce a new builtin exception, UnboundLocalError, raised when ceval.c
tries to retrieve or delete a local name that isn't bound to a value.
Currently raises NameError, which makes this behavior a FAQ since the same
error is raised for "missing" global names too: when the user has a global
of the same name as the unbound local, NameError makes no sense to them.
Even in the absence of shadowing, knowing whether a bogus name is local or
global is a real aid to quick understanding.
Example:
D:\src\PCbuild>type local.py
x = 42
def f():
print x
x = 13
return x
f()
D:\src\PCbuild>python local.py
Traceback (innermost last):
File "local.py", line 8, in ?
f()
File "local.py", line 4, in f
print x
UnboundLocalError: x
D:\src\PCbuild>
Note that UnboundLocalError is a subclass of NameError, for compatibility
with existing class-exception code that may be trying to catch this as a
NameError. Unfortunately, I see no way to make this wholly compatible
with -X (see comments in bltinmodule.c): under -X, [UnboundLocalError
is an alias for NameError --GvR].
[The ceval.c patch differs slightly from the second version that Tim
submitted; I decided not to raise UnboundLocalError for DELETE_NAME,
only for DELETE_LOCAL. DELETE_NAME is only generated at the module
level, and since at that level a NameError is raised for referencing
an undefined name, it should also be raised for deleting one.]
We occasionally received reports from people getting "invalid tstate"
crashes (this is a fatal error in PyThreadState_Delete()). Finally
several people were able to reproduce it reliably and Tim Peters
discovered that there is a race condition when multiple threads are
calling this function without holding the global interpreter lock (the
function may be called without holding that).
Solved the race condition by adding a lock around the mutating uses of
interp->tstate_head. Tim and Jonathan Giddy have run tests that make
it likely that this fixes the crashes -- although Tim hasn't heard
from the person who reported the original problem.
ExtensionClasses in isinstance() and issubclass().
- abstract instance and class protocols are used *only* in those
cases that would generate errors before the patch. That is, there's
no penalty for the normal case.
- instance protocol: an object smells like an instance if it
has a __class__ attribute that smells like a class.
- class protocol: an object smells like a class if it has a
__bases__ attribute that is a tuple with elements that
smell like classes (although not all elements may actually get
sniffed ;).
man pages suggest that the proper thing to do is to add THR_NEW_LWP to
the flags on thr_create(), and that there really isn't a downside, so
I'll do that.
"""
Spec says that on success pthread_create returns 0. It does not say
that an error code will be < 0. Linux glibc2 pthread_create() returns
ENOMEM (12) when one exceed process limits. (It looks like it should
return EAGAIN, but that's another story.)
For reference, see:
http://www.opengroup.org/onlinepubs/7908799/xsh/pthread_create.html
"""
[I have a feeling that similar bugs were fixed before; perhaps someone
could check that all error checks no check for != 0?]
xrange(), especially for platforms where int and long are different
sizes (so sys.maxint isn't actually the theoretical limit for the
length of a list, but the largest C int is -- sys.maxint is the
largest Python int, which is actually a C long).
test for classes with a __complex__() method. The attribute is pulled
out of the instance with PyObject_GetAttr() but this transfers
ownership and the function object was never DECREF'd.
v temporary variable was never decref'd. Test this by starting up the
interpreter, hitting C-c, then immediately exiting.
Same potential leak can occur if error is E_NOMEM, since the return is
done in the case block. Added Py_XDECREF(v); to both blocks, just
before the return.
think we have our own DOS box (i.e. we're not started from a command
line shell), we print a message and wait for the user to hit a key
before the DOS box is closed.
The hacky heuristic for determining whether we have our *own* DOS box
(due to Mark Hammond) is to test whether we're on line zero...
The following patches (relative to 1.5.2b1) enable Python dynamic
loading to work on NetBSD platforms that use ELF (presnetly mips and
alpha systems). They automaticly determine wether the system is ELF or
a.out rather than using astatic list of platforms so that when other
NetBSD platforms move to ELF, python will continue to work without
change.
In other words, hex(sys.hexversion) == 0x010502b2 for Python 1.5.2b2.
This is derived from the new variable PY_VERSION_HEX defined in patchlevel.h.
(Cute, eh?)
Also (non-BSDI specific):
- Change the CHECK_STATUS() macro so it tests for nonzero error codes
instead of negative error codes only (this was needed for BSDI, but
appears to be correct according to the PTHREADS spec).
- use memset() to zero out the allocated lock structure. Again, this
was needed for BSDI, but can't hurt elsewhere either.
initialization of class exceptions. Specifically:
init_class_exc(): This function now returns an integer status of the
class exception initialization. No fatal errors in this method now.
Also, use PySys_WriteStderr() when writing error messages. When an
error occurs in this function, 0 is returned, but the partial creation
of the exception classes is not undone (this happens elsewhere).
Things that could trigger the fallback:
- exceptions.py fails to be imported (due to syntax error, etc.)
- one of the exception classes is missing (e.g. due to library
version mismatch)
- exception class can't be inserted into __builtin__'s dictionary
- MemoryError instance can't be pre-allocated
- some other PyErr_Occurred
newstdexception(): Changed the error message. This is still a fatal
error because if the string based exceptions can't be created, we
really can't continue.
initerrors(): Be sure to xdecref the .exc field, which might be
non-NULL if class exceptions init was aborted.
_PyBuiltin_Init_2(): If class exception init fails, print a warning
message and reinstate the string based exceptions.
that file in fact did not exist or at least was not used. Change this
so that __file__ is *only* set to the .pyc/.pyo file when it actually
read the code object from it; otherwise __file__ is set to the .py
file.
happen when you use a non-keyword argument after a keyword argument,
and in this case you also get a syntax error. I fully suspect that
the underflow is caused by the code that stops generating code when it
detects the syntax error, but I can't find the culprit right now. I
know, I know.)
The MS compiler doesn't call it 'long long', it uses __int64,
so a new #define, LONG_LONG, has been added and all occurrences
of 'long long' are replaced with it.
This is a patch that Bill Bummgarner did for 1.4 that hasn't made its
way into the distribution yet. This is important if you want to use
the ObjC module.
frozen packages. (I *think* this means that we can now have a
built-in module bar that's a submodule of a frozen package foo, by
registering the built-in module with a name "foo.bar" in the table of
builtin modules.)
Guido van Rossum
Barry Warsaw
Fred Drake