Bug 1003935: xrange overflows

Added XXX comment about why the undocumented PyRange_New() API function
is too broken to be worth the considerable pain of repairing.

Changed range_new() to stop using PyRange_New().  This fixes a variety
of bogus errors.  Nothing in the core uses PyRange_New() now.

Documented that xrange() is intended to be simple and fast, and that
CPython restricts its arguments, and length of its result sequence, to
native C longs.

Added some tests that failed before the patch, and repaired a test that
relied on a bogus OverflowError getting raised.

1 files changed, 15 insertions, 9 deletions

diff --git a/Doc/lib/libfuncs.tex b/Doc/lib/libfuncs.tex
index 062e3e8..1d4df67 100644
--- a/Doc/lib/libfuncs.tex
+++ b/Doc/lib/libfuncs.tex
@@ -79,7 +79,7 @@ def my_import(name):
 
   \indexii{Boolean}{type}
   \versionadded{2.2.1}
-  \versionchanged[If no argument is given, this function returns 
+  \versionchanged[If no argument is given, this function returns
                   \constant{False}]{2.3}
 \end{funcdesc}
 
@@ -379,7 +379,7 @@ class C:
   that differentiate between binary and text files (else it is
   ignored).  If the file cannot be opened, \exception{IOError} is
   raised.
-  
+
   In addition to the standard \cfunction{fopen()} values \var{mode}
   may be \code{'U'} or \code{'rU'}. If Python is built with universal
   newline support (the default) the file is opened as a text file, but
@@ -392,7 +392,7 @@ class C:
   \var{mode} \code{'U'} is the same as normal text mode.  Note that
   file objects so opened also have an attribute called
   \member{newlines} which has a value of \code{None} (if no newlines
-  have yet been seen), \code{'\e n'}, \code{'\e r'}, \code{'\e r\e n'}, 
+  have yet been seen), \code{'\e n'}, \code{'\e r'}, \code{'\e r\e n'},
   or a tuple containing all the newline types seen.
 
   If \var{mode} is omitted, it defaults to \code{'r'}.  When opening a
@@ -459,7 +459,7 @@ class C:
   the inner sets should also be \class{frozenset} objects.  If
   \var{iterable} is not specified, returns a new empty set,
   \code{frozenset([])}.
-  \versionadded{2.4}  
+  \versionadded{2.4}
 \end{funcdesc}
 
 \begin{funcdesc}{getattr}{object, name\optional{, default}}
@@ -659,7 +659,7 @@ class C:
 \end{funcdesc}
 
 \begin{funcdesc}{object}{}
-  Return a new featureless object.  \function{object()} is a base 
+  Return a new featureless object.  \function{object()} is a base
   for all new style classes.  It has the methods that are common
   to all instances of new style classes.
   \versionadded{2.2}
@@ -901,7 +901,7 @@ except NameError:
   must be immutable.  To represent sets of sets, the inner sets should
   be \class{frozenset} objects.  If \var{iterable} is not specified,
   returns a new empty set, \code{set([])}.
-  \versionadded{2.4}  
+  \versionadded{2.4}
 \end{funcdesc}
 
 \begin{funcdesc}{setattr}{object, name, value}
@@ -931,7 +931,7 @@ except NameError:
   Return a new sorted list from the items in \var{iterable}.
   The optional arguments \var{cmp}, \var{key}, and \var{reverse}
   have the same meaning as those for the \method{list.sort()} method.
-  \versionadded{2.4}    
+  \versionadded{2.4}
 \end{funcdesc}
 
 \begin{funcdesc}{staticmethod}{function}
@@ -1099,6 +1099,12 @@ It's a function
   them) except when a very large range is used on a memory-starved
   machine or when all of the range's elements are never used (such as
   when the loop is usually terminated with \keyword{break}).
+
+  \note{\function{xrange()} is intended to be simple and fast.
+        Implementations may impose restrictions to achieve this.
+        The C implementation of Python restricts all arguments to
+        native C longs ("short" Python integers), and also requires
+        that that number of elements fit in a native C long.}
 \end{funcdesc}
 
 \begin{funcdesc}{zip}{\optional{seq1, \moreargs}}
@@ -1114,11 +1120,11 @@ It's a function
 
   \versionchanged[Formerly, \function{zip()} required at least one argument
   and \code{zip()} raised a \exception{TypeError} instead of returning
-  an empty list.]{2.4} 
+  an empty list.]{2.4}
 \end{funcdesc}
 
 
-% ---------------------------------------------------------------------------	
+% ---------------------------------------------------------------------------
 
 
 \section{Non-essential Built-in Functions \label{non-essential-built-in-funcs}}