* system.base packages and packages other than system.base's have no dependency

relationship. 

  So this is the quickest and safest way i think by not touching the dependency code,
  and leaving it generic for any package.

  The dependency ordering relations of these two groups (system.base packages and other
  than system.base packages) are handled within each other. 

  the systembase_order holds this relational dependency order, the "order" variable holds
  the not system.base packages relational dependency order. 

  So by combining these as systebase_order + order the dependency relations should not
  be harmed and the system.base packages first rule is satisfied.

BUG:FIXED:4211

pisi/api.py

@@ -222,7 +222,7 @@ def generate_base_upgrade(A):
     # method returns the currently needed system.base component install and 
     # upgrade needs
     base = upgrade_base(A, ignore_package_conflicts = True)
-    return list(base)
+    return base
 
 def generate_conflicts(A):
     # returns the conflicting packages list of the to be installed packages.

pisi/operations.py

@@ -298,7 +298,7 @@ def upgrade_base(A = set(), ignore_package_conflicts = False):
                                util.strlist(extra_upgrades))
                 G_f, upgrade_order = plan_upgrade(extra_upgrades, ignore_build)
             # return packages that must be added to any installation
-            return set(install_order + upgrade_order)
+            return install_order + upgrade_order
         else:
             ctx.ui.warning(_('Safety switch: the component system.base cannot be found'))
     return set()
@@ -325,7 +325,7 @@ def install_pkg_names(A, reinstall = False):
         ctx.ui.info(_('No packages to install.'))
         return
 
-    A |= upgrade_base(A)
+    systembase_order = upgrade_base(A)
 
     if not ctx.config.get_option('ignore_dependency'):
         G_f, order = plan_install_pkg_names(A)
@@ -333,6 +333,8 @@ def install_pkg_names(A, reinstall = False):
         G_f = None
         order = list(A)
 
+    order = systembase_order + order
+
     if len(order) > 1:
         ctx.ui.info(_("Following packages will be installed in the respective "
                       "order to satisfy dependencies:\n") + util.strlist(order))
@@ -448,7 +450,7 @@ def upgrade_pkg_names(A = []):
         ctx.ui.info(_('No packages to upgrade.'))
         return True
 
-    A |= upgrade_base(A)
+    systembase_order = upgrade_base(A)
 
     ctx.ui.debug('A = %s' % str(A))
 
@@ -458,6 +460,8 @@ def upgrade_pkg_names(A = []):
         G_f = None
         order = list(A)
 
+    order = systembase_order + order
+
     if not ctx.get_option('ignore_package_conflicts'):
         conflicts = check_conflicts(order, ctx.packagedb)