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Add UnicodeWarning

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Andrew M. Kuchling 2006-08-16 13:22:20 +00:00
parent 581795902d
commit efd68c789e
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34
Doc/whatsnew/whatsnew25.tex
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@ -1184,6 +1184,35 @@ a line like this near the top of the source file:
# -*- coding: latin1 -*- # -*- coding: latin1 -*-
\end{verbatim} \end{verbatim}
\item A new warning, \class{UnicodeWarning}, is triggered when
you attempt to compare a Unicode string and an 8-bit string
that can't be converted to Unicode using the default ASCII encoding.
The result of the comparison is false:
\begin{verbatim}
>>> chr(128) == unichr(128) # Can't convert chr(128) to Unicode
__main__:1: UnicodeWarning: Unicode equal comparison failed
to convert both arguments to Unicode - interpreting them
as being unequal
False
>>> chr(127) == unichr(127) # chr(127) can be converted
True
\end{verbatim}
Previously this would raise a \class{UnicodeDecodeError} exception,
but in 2.5 this could result in puzzling problems when accessing a
dictionary. If you looked up \code{unichr(128)} and \code{chr(128)}
was being used as a key, you'd get a \class{UnicodeDecodeError}
exception. Other changes in 2.5 resulted in this exception being
raised instead of suppressed by the code in \file{dictobject.c} that
implements dictionaries.
Raising an exception for such a comparison is strictly correct, but
the change might have broken code, so instead
\class{UnicodeWarning} was introduced.
(Implemented by Marc-Andr\'e Lemburg.)
\item One error that Python programmers sometimes make is forgetting \item One error that Python programmers sometimes make is forgetting
to include an \file{__init__.py} module in a package directory. to include an \file{__init__.py} module in a package directory.
Debugging this mistake can be confusing, and usually requires running Debugging this mistake can be confusing, and usually requires running
@ -2423,6 +2452,11 @@ was always a frame object. Because of the \pep{342} changes
described in section~\ref{pep-342}, it's now possible described in section~\ref{pep-342}, it's now possible
for \member{gi_frame} to be \code{None}. for \member{gi_frame} to be \code{None}.
\item A new warning, \class{UnicodeWarning}, is triggered when
you attempt to compare a Unicode string and an 8-bit string that can't
be converted to Unicode using the default ASCII encoding. Previously
such comparisons would raise a \class{UnicodeDecodeError} exception.
\item Library: the \module{csv} module is now stricter about multi-line quoted \item Library: the \module{csv} module is now stricter about multi-line quoted
fields. If your files contain newlines embedded within fields, the fields. If your files contain newlines embedded within fields, the
input should be split into lines in a manner which preserves the input should be split into lines in a manner which preserves the