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]
Summary: Mercurial -- a distributed SCM
Name: mercurial
Version: 0.6
Release: 1
Copyright: GPL
Group: Development/Tools
Distribution: RedHat
Source: http://www.selenic.com/mercurial/release/%{name}-%{version}.tar.gz
Packager: Arun Sharma <arun@sharma-home.net>
Prefix: /usr
BuildRoot: /tmp/build.%{name}-%{version}-%{release}
%define pythonver %(python -c 'import sys;print ".".join(map(str, sys.version_info[:2]))')
%define pythonlib %{_libdir}/python%{pythonver}/site-packages/%{name}
%description
Mercurial is a fast, lightweight source control management system designed
for efficient handling of very large distributed projects.
%prep
rm -rf $RPM_BUILD_ROOT
%setup -q -n %{name}-%{version}
%build
python setup.py build
%install
python setup.py install --root $RPM_BUILD_ROOT
%clean
rm -rf $RPM_BUILD_ROOT
%files
%defattr(-,root,root,-)
%doc doc
%dir %{pythonlib}
%{_bindir}/hgmerge
%{_bindir}/hg
%{pythonlib}/templates
%{pythonlib}/*.pyc
%{pythonlib}/*.py
%{pythonlib}/*.so