[Nix-dev] DbEnv::open: No such file or directory - not very helpful

[Marc Weber]

After adding a debug line

    try {
>>>>>   printMsg(lvlTalkative, "trying to access nix database "+nixDBPath);
        nixDB.open(nixDBPath);
    } catch (DbNoPermission & e) {
        printMsg(lvlTalkative, "cannot access Nix database; continuing anyway");
        readOnlyMode = true;
        return;
    }

I got:

$ nix-env.exe -I /cygdrive/e/nix/nixsvn/trace/nixpkgs/trunk/default.nix 
trying to access nix database /nix/var/nix/db
opening database environment
environment open failed: DbEnv::open: No such file or directory
error: DbEnv::open: No such file or directory

which showed me that /nix/var/nix/db is the broblem.

I could fix it by creating that directory.
Would it be bossible to create it/ check existance automatically
somehow?

Or did I miss something?

Marc