Re: [Python-Dev] Raising OSError concrete classes from errno code
Thanks for the elaboration! On Wed, Dec 26, 2012 at 6:42 PM, Antoine Pitrou wrote: > On Wed, 26 Dec 2012 13:37:13 +0200 > Andrew Svetlov wrote: >> > >> > As Serhiy's example shows, this mapping of error numbers to subclasses >> > is implemented directly in OSError.__new__. We did this so that code >> > could catch the new exceptions, even when dealing with old code that >> > raises the legacy exception types. >> > >> Sorry. >> Looks like OSError.__new__ requires at least two arguments for >> executing subclass search mechanism: >> >> >>> OSError(errno.ENOENT) >> OSError(2,) >> >>> OSError(errno.ENOENT, 'error msg') >> FileNotFoundError(2, 'error msg') > > Indeed, it does. I did this for consistency, because calling OSError > with only one argument doesn't set the "errno" attribute at all: > e = OSError(5) e.errno > > Regards > > Antoine. > > > ___ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/andrew.svetlov%40gmail.com -- Thanks, Andrew Svetlov ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Raising OSError concrete classes from errno code
On Wed, 26 Dec 2012 13:37:13 +0200 Andrew Svetlov wrote: > > > > As Serhiy's example shows, this mapping of error numbers to subclasses > > is implemented directly in OSError.__new__. We did this so that code > > could catch the new exceptions, even when dealing with old code that > > raises the legacy exception types. > > > Sorry. > Looks like OSError.__new__ requires at least two arguments for > executing subclass search mechanism: > > >>> OSError(errno.ENOENT) > OSError(2,) > >>> OSError(errno.ENOENT, 'error msg') > FileNotFoundError(2, 'error msg') Indeed, it does. I did this for consistency, because calling OSError with only one argument doesn't set the "errno" attribute at all: >>> e = OSError(5) >>> e.errno >>> Regards Antoine. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Raising OSError concrete classes from errno code
It sould be in Python-Ideas: add keyword argument support for OSError and subclasses with suitable default values. I.e. >>> OSError(errno=errno.ENOENT) FileNotFoundError(2, 'No such file or directory') >>> FileNotFoundError(filename='qwerty') FileNotFoundError(2, 'No such file or directory') >>> FileNotFoundError(strerr='Bad file') FileNotFoundError(2, 'Bad file') ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Raising OSError concrete classes from errno code
On Wed, Dec 26, 2012 at 12:16 PM, Nick Coghlan wrote: > On Wed, Dec 26, 2012 at 6:50 PM, Serhiy Storchaka wrote: >> On 25.12.12 23:55, Andrew Svetlov wrote: >>> >>> Currently we have exception tree of classes inherited from OSError >>> When we use C API we can call PyErr_SetFromErrno and >>> PyErr_SetFromErrnoWithFilename[Object] functions. >>> This ones raise concrete exception class (FileNotFoundError for >>> example) looking on implicit errno value. >>> I cannot see the way to do it from python. >> >> > raise OSError(errno.ENOENT, 'No such file or directory', 'qwerty') >> Traceback (most recent call last): >> File "", line 1, in >> FileNotFoundError: [Errno 2] No such file or directory: 'qwerty' > > As Serhiy's example shows, this mapping of error numbers to subclasses > is implemented directly in OSError.__new__. We did this so that code > could catch the new exceptions, even when dealing with old code that > raises the legacy exception types. > Sorry. Looks like OSError.__new__ requires at least two arguments for executing subclass search mechanism: >>> OSError(errno.ENOENT) OSError(2,) >>> OSError(errno.ENOENT, 'error msg') FileNotFoundError(2, 'error msg') I had tried first one and got confuse. > http://docs.python.org/3/library/exceptions#OSError could probably do > with an example like the one quoted in order to make this clearer > Added http://bugs.python.org/issue16785 for this. > Cheers, > Nick. > > > -- > Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia > ___ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/andrew.svetlov%40gmail.com -- Thanks, Andrew Svetlov ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Raising OSError concrete classes from errno code
On Wed, Dec 26, 2012 at 6:50 PM, Serhiy Storchaka wrote: > On 25.12.12 23:55, Andrew Svetlov wrote: >> >> Currently we have exception tree of classes inherited from OSError >> When we use C API we can call PyErr_SetFromErrno and >> PyErr_SetFromErrnoWithFilename[Object] functions. >> This ones raise concrete exception class (FileNotFoundError for >> example) looking on implicit errno value. >> I cannot see the way to do it from python. > > raise OSError(errno.ENOENT, 'No such file or directory', 'qwerty') > Traceback (most recent call last): > File "", line 1, in > FileNotFoundError: [Errno 2] No such file or directory: 'qwerty' As Serhiy's example shows, this mapping of error numbers to subclasses is implemented directly in OSError.__new__. We did this so that code could catch the new exceptions, even when dealing with old code that raises the legacy exception types. http://docs.python.org/3/library/exceptions#OSError could probably do with an example like the one quoted in order to make this clearer Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Raising OSError concrete classes from errno code
On 25.12.12 23:55, Andrew Svetlov wrote: Currently we have exception tree of classes inherited from OSError When we use C API we can call PyErr_SetFromErrno and PyErr_SetFromErrnoWithFilename[Object] functions. This ones raise concrete exception class (FileNotFoundError for example) looking on implicit errno value. I cannot see the way to do it from python. >>> raise OSError(errno.ENOENT, 'No such file or directory', 'qwerty') Traceback (most recent call last): File "", line 1, in FileNotFoundError: [Errno 2] No such file or directory: 'qwerty' ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Raising OSError concrete classes from errno code
static method is better than new builtin function, agree. On Wed, Dec 26, 2012 at 12:03 AM, Benjamin Peterson wrote: > 2012/12/25 Andrew Svetlov : >> Currently we have exception tree of classes inherited from OSError >> When we use C API we can call PyErr_SetFromErrno and >> PyErr_SetFromErrnoWithFilename[Object] functions. >> This ones raise concrete exception class (FileNotFoundError for >> example) looking on implicit errno value. >> I cannot see the way to do it from python. >> >> Maybe adding builtin like exception_from_errno(errno, filename=None) >> make some value? >> Function returns exception instance, concrete class depends of errno value > > I think a static method on OSError like .from_errno would be good. > > > -- > Regards, > Benjamin -- Thanks, Andrew Svetlov ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Raising OSError concrete classes from errno code
2012/12/25 Andrew Svetlov : > Currently we have exception tree of classes inherited from OSError > When we use C API we can call PyErr_SetFromErrno and > PyErr_SetFromErrnoWithFilename[Object] functions. > This ones raise concrete exception class (FileNotFoundError for > example) looking on implicit errno value. > I cannot see the way to do it from python. > > Maybe adding builtin like exception_from_errno(errno, filename=None) > make some value? > Function returns exception instance, concrete class depends of errno value I think a static method on OSError like .from_errno would be good. -- Regards, Benjamin ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] Raising OSError concrete classes from errno code
Currently we have exception tree of classes inherited from OSError When we use C API we can call PyErr_SetFromErrno and PyErr_SetFromErrnoWithFilename[Object] functions. This ones raise concrete exception class (FileNotFoundError for example) looking on implicit errno value. I cannot see the way to do it from python. Maybe adding builtin like exception_from_errno(errno, filename=None) make some value? Function returns exception instance, concrete class depends of errno value For example if I've got EPOLLERR from poller call I can get error code via s.getsockopt(SOL_SOCKET, SO_ERROR) but I cannot raise concrete exception from given errno code. -- Thanks, Andrew Svetlov ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
