How configuration files are handled during an upgrade

Note: this page is still valid but less important due to the new recommended upgrade procedure.

Configuration files are files in R syntax which assign numbers, strings, lists etc. to names.  radR reads these as a list of named items.  Current configuration files are named XXX.conf.R, and configuration files in a new installation are named XXX.conf.update.R

Briefly:  if the file XXX.conf.update.R exists, it is presumed to be an update, and any items in it but not in XXX.conf.R are added to the latter. If an item is in XXX.conf.R but not in XXX.conf.update.R, it is removed, on the assumption that the new version of radR has made the item obsolete. The file XXX.conf.update.R is renamed so that the update only occurs once.

In detail:  the following procedure from radRutil.R:rss.do.load.config() is applied to each configurable object XXX:

if the file XXX.conf.update.R exists
    read LIST from it
    rename XXX.conf.update.R to XXX.conf.factory.R (deleting any old copy)
    if the file XXX.conf.R exists
      update LIST from the file XXX.conf.R, overwriting any entries
             already in LIST, but not adding any not already there
      rename XXX.conf.R to XXX.conf.old.R (deleting any old copy)
    endif
    copy XXX.conf.factory.R to XXX.conf.R (needed for rewrite)
    rewrite LIST to XXX.conf.R
 else
    read LIST from XXX.conf.R, if it exists