SF patch 637176: list.sort crasher

Armin Rigo's Draconian but effective fix for

SF bug 453523: list.sort crasher

slightly fiddled to catch more cases of list mutation.  The dreaded
internal "immutable list type" is gone!  OTOH, if you look at a list
*while* it's being sorted now, it will appear to be empty.  Better
than a core dump.

1 files changed, 7 insertions, 1 deletions

diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex
index 49cb67b..3e788bb 100644
--- a/Doc/lib/libstdtypes.tex
+++ b/Doc/lib/libstdtypes.tex
@@ -922,7 +922,7 @@ The following operations are defined on mutable sequence types (where
   \lineiii{\var{s}.reverse()}
 	{reverses the items of \var{s} in place}{(6)}
   \lineiii{\var{s}.sort(\optional{\var{cmpfunc}})}
-	{sort the items of \var{s} in place}{(6), (7), (8)}
+	{sort the items of \var{s} in place}{(6), (7), (8), (9)}
 \end{tableiii}
 \indexiv{operations on}{mutable}{sequence}{types}
 \indexiii{operations on}{sequence}{types}
@@ -980,6 +980,12 @@ Notes:
   Python 2.2.  The C implementation of Python 2.3 introduced a stable
   \method{sort()} method, but code that intends to be portable across
   implementations and versions must not rely on stability.
+
+\item[(9)] While a list is being sorted, the effect of attempting to
+  mutate, or even inspect, the list is undefined.  The C implementation
+  of Python 2.3 makes the list appear empty for the duration, and raises
+  \exception{ValueError} if it can detect that the list has been
+  mutated during a sort.
 \end{description}