Mercurial > hg > mercurial-crew-with-dirclash
view hgmerge @ 827:a61728b58dc0
Fix array overflow bug in bdiff
I ran into a bug while importing a large repository into mercurial.
The diff algorithm does not allocate a big enough array of hunks
for some test cases. This results in memory corruption, and possibly,
as in my case, a seg fault.
You should be able to reproduce this problem with any case of more
than a few lines that follows this pattern:
a b
= =
1 1
2
2 3
4
3 5
.
4 .
.
5
.
.
.
I.e., "a" has blank lines on every other line that have been removed in
"b". In this case, the number of matching hunks is equal to the number
of lines in "b". This is more than ((an + bn)/4 + 2). I'm not sure what
motivates this formula, but when I changed it to the smaller of an or
bn (+ 1), it works.
[comment added by mpm]
author | "Wallace, Eric S" <eric.s.wallace@intel.com> |
---|---|
date | Thu, 04 Aug 2005 13:25:59 -0800 |
parents | 0902ffece4b4 |
children | 7a6acd56cd5a 1fe3b14c7044 9c918287d10b |
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#!/bin/sh # # hgmerge - default merge helper for Mercurial # # This tries to find a way to do three-way merge on the current system. # The result ought to end up in $1. set -e # bail out quickly on failure LOCAL="$1" BASE="$2" OTHER="$3" if [ -z "$EDITOR" ]; then EDITOR="vi" fi # Back up our file cp "$LOCAL" "$LOCAL.orig" # Attempt to do a non-interactive merge if type merge > /dev/null ; then if merge "$LOCAL" "$BASE" "$OTHER" 2> /dev/null; then # success! exit 0 fi cp "$LOCAL.orig" "$LOCAL" elif type diff3 > /dev/null ; then if diff3 -m "$LOCAL.orig" "$BASE" "$OTHER" > "$LOCAL" ; then # success exit 0 fi cp "$LOCAL.orig" "$LOCAL" fi if [ -n "$DISPLAY" ]; then # try using kdiff3, which is fairly nice if type kdiff3 > /dev/null ; then if kdiff3 --auto "$BASE" "$LOCAL" "$OTHER" -o "$LOCAL" ; then exit 0 else exit 1 fi fi # try using tkdiff, which is a bit less sophisticated if type tkdiff > /dev/null ; then if tkdiff "$LOCAL" "$OTHER" -a "$BASE" -o "$LOCAL" ; then exit 0 else exit 1 fi fi fi # Attempt to do a merge with $EDITOR if type merge > /dev/null ; then echo "conflicts detected in $LOCAL" merge "$LOCAL" "$BASE" "$OTHER" 2>/dev/null || $EDITOR "$LOCAL" exit 0 fi if type diff3 > /dev/null ; then echo "conflicts detected in $LOCAL" diff3 -m "$LOCAL.orig" "$BASE" "$OTHER" > "$LOCAL" || $EDITOR "$LOCAL" exit 0 fi HGTMP="" cleanup_exit() { rm -rf "$HGTMP" exit $1 } # attempt to manually merge with diff and patch if type diff > /dev/null ; then if type patch > /dev/null ; then # Remove temporary files even if we get interrupted trap "cleanup_exit 1" TERM KILL INT QUIT ABRT HGTMP="${TMPDIR-/tmp}/hgmerge.$RANDOM.$RANDOM.$RANDOM.$$" (umask 077 && mkdir "$HGTMP") || { echo "Could not create temporary directory! Exiting." 1>&2 exit 1 } diff -u "$BASE" "$OTHER" > "$HGTMP/diff" if patch "$LOCAL" < "$HGTMP/diff" ; then cleanup_exit 0 else $EDITOR "$LOCAL" "$LOCAL.rej" fi cleanup_exit 1 fi fi echo "hgmerge: unable to find merge, tkdiff, kdiff3, or diff+patch!" exit 1