Comment 7 for bug 1288718

This bug has been fixed upstream in commit b68ce88357daf362e60d7f8f131041289c8db690

http://anonscm.debian.org/gitweb/?p=apt/apt.git;a=commit;h=b68ce88357daf362e60d7f8f131041289c8db690

commit b68ce88357daf362e60d7f8f131041289c8db690
Author: Julian Andres Klode <email address hidden>
Date: Mon Mar 17 13:43:12 2014 +0100

    apt-inst: Do not try to create a substring of an empty string in error reporting

    One of our compressors (the empty one) has an empty extension. Calling substr
    on it fails.

diff --git a/apt-inst/deb/debfile.cc b/apt-inst/deb/debfile.cc
index 3803329..a63cb67 100644
--- a/apt-inst/deb/debfile.cc
+++ b/apt-inst/deb/debfile.cc
@@ -124,8 +124,10 @@ bool debDebFile::ExtractTarMember(pkgDirStream &Stream,const char *Name)
    {
       std::string ext = std::string(Name) + ".{";
       for (std::vector<APT::Configuration::Compressor>::const_iterator c = compressor.begin();
- c != compressor.end(); ++c)
- ext.append(c->Extension.substr(1));
+ c != compressor.end(); ++c) {
+ if (!c->Extension.empty())
+ ext.append(c->Extension.substr(1));
+ }
       ext.append("}");
       return _error->Error(_("Internal error, could not locate member %s"), ext.c_str());
    }