problem with local packages taking precedence over global and (an apparent) solution

[Sergei Steshenko]

Hello,

this is regarding functionality of 'octave-3.6.1/scripts/pkg/pkg.m' file.

After installing packages both locally and globally I've noticed that both 
global and local packages were listed by 'pkg list', and they were both listed 
as autoloaded.

I did request autoloading in both cases, so it is not a problem, the problem is 
that both local and global - if I understand correctly, local packages should 
take precedence.

Looking into 'octave-3.6.1/scripts/pkg/pkg.m' file contents I came to the 
conclusion (thanks to the comment) I came to the conclusion that the desired 
functionality is supposed to be implemented by line #1988..2004:



   1972 function [out1, out2] = installed_packages (local_list, global_list)
   1973   ## Get the list of installed packages.
   1974   try
   1975     local_packages = load (local_list).local_packages;
   1976   catch
   1977     local_packages = {};
   1978   end_try_catch
   1979   try
   1980     global_packages = load (global_list).global_packages;
   1981   catch
   1982     global_packages = {};
   1983   end_try_catch
   1984   installed_pkgs_lst = {local_packages{:}, global_packages{:}};
   1985
   1986   ## Eliminate duplicates in the installed package list.
   1987   ## Locally installed packages take precedence.
   1988   dup = [];
   1989   for i = 1:length (installed_pkgs_lst)
   1990     if (find (dup, i))
   1991       continue;
   1992     endif
   1993     for j = (i+1):length (installed_pkgs_lst)
   1994       if (find (dup, j))
   1995         continue;
   1996       endif
   1997       if (strcmp (installed_pkgs_lst{i}.name, 
installed_pkgs_lst{j}.name))
   1998         dup = [dup, j];
   1999       endif
   2000     endfor
   2001   endfor
   2002   if (! isempty(dup))
   2003     installed_pkgs_lst(dup) = [];
   2004   endif

.

Alas, inserting diagnostic prints I verified that after the code is executed, 
the duplicates (i.e. local and global packages with the same name) are still 
there.


I tried to understand the logic of the code, but failed. So I simply rewrote 
the piece of code, and it seems to work OK now. Here's how the code looks now:


function [out1, out2] = installed_packages (local_list, global_list)
  ## Get the list of installed packages.
  try
    local_packages = load (local_list).local_packages;
  catch
    local_packages = {};
  end_try_catch
  try
    global_packages = load (global_list).global_packages;
  catch
    global_packages = {};
  end_try_catch

  #  ## Eliminate duplicates in the installed package list.
  #  ## Locally installed packages take precedence.

  installed_pkgs_lst = local_packages;

  for global_pkg_num = 1:length(global_packages)
    global_pkg_is_not_a_local_duplicate = 1;

    for local_pkg_num = 1:length(local_packages)
      if(strcmp(local_packages{local_pkg_num}.name, 
global_packages{global_pkg_num}.name))
        global_pkg_is_not_a_local_duplicate = 0;
        break;
      endif
    endfor

    if(global_pkg_is_not_a_local_duplicate)
      installed_pkgs_lst = {installed_pkgs_lst{:}, 
global_packages{global_pkg_num}};
    endif
  endfor

.

The code is simpler, and is as bad O(N ^ 2)) as the original one, but for less 
than 100 packages currently available the computational complexity doesn't 
matter.


My currently used version of 'pkg.m' file ('pkg.m.20120521.gz') with this and 
other fixes is attached.


Among other fixes:

1) locally installed packaged are under ~/octave-X.Y.Z directory and _not_ 
under ~/octave directory => no more clashes/unpredictable behavior because of 
old version packages;


2) likewise, list of locally installed packages is in ~/.octave_packages-X.Y.Z 
file and _not_ in ~/.octave_packages file.


Regards,
  Sergei.

pkg.m.20120521.gz
Description: GNU Zip compressed data