insensitive-case.rst

Insensitive case

Configuration

• Introduce the :mconfig:`icase` option name
  • Which is made persistent through the :envvar:`MODULES_ICASE` environment variable
  • Many people asked for separate options as applying an icase approach to a module loading context is not seen desired by everybody whereas it is in an module search context
  • Defined levels of enablement are:
    • never
    • search
    • always
  • icase option will be set by default to
    • never in v4 not to change existing behaviors
    • search in v5 as it seems to be a general improvement for everybody
  • A command-line switch :option:`--icase` (short form :option:`-i`) is added
    • Was there in Modules 3 (for search sub-command only)
    • When set, equals to an always icase mode
• No immediate need for a --no-icase command-line switch
  • Combining configuration option and --icase command-line switch seems sufficient

Specification

• When enabled, match query string in a case insensitive manner
  • query soFT returns soft, SOFT, soFT, SOft, sOft and so on
• In case multiple files correspond to the same icase word
  • like soft, soFT, SoFt, SOFT filenames
  • query SOFT returns SOFT (exact match is returned among possibilities)
  • query SoFt returns SoFt (exact match is returned among possibilities)
  • query SOft returns soft (highest lexicographically sorted match is returned among possibilities)
  • query soFt returns soft (highest lexicographically sorted match is returned among possibilities)
• When icase is enabled for search context it applies to
  • module specification passed as argument in following context:
    • :ref:`module_version_specification_to_return_all_matching_modules`
• When icase is enabled for all context it applies to
  • search context like described above
  • module specification passed as argument in following contexts:
    • :ref:`module_version_specification_to_select_one_module`
    • :ref:`module_version_specification_to_check_compatibility`
  • module alias and symbolic version resolution triggered by
    • module-info alias
    • module-info version
    • getPathToModule
    • isModuleEvaluated
  • the gathering of all module alias and symbolic version targeting a given module
    • this is processed by getAllModuleResolvedName procedure
    • which is called by
      • doesLoadingModuleMatchesName
      • cmdModuleLoad
• Note that whatis specification passed as argument to the search sub-command is always matched in a case insensitive manner

Corner cases

• When looking for the best match among loaded modules to select one module to unload, lastly loaded module, or firstly loaded module depending on :mconfig:`unload_match_order` configuration, will be returned
  • When insensitive case is enabled, last or first icase match will be returned even if an exact match is present among the loaded module list
  • This behavior has an impact in case multiple available modules correspond to the same insensitive case string
    • For instance iCaSe and IcAsE modules
• When icase is enabled on all contexts and multiple directories match same icase module name
  • for instance following modules exist: ICASE/1.1, icase/1.2, iCaSe/1.3 and iCaSe/1.4
  • a module avail -i icase will sort iCaSe/1.4 as the highest entry
  • however a module load -i icase command will load icase/1.2
    • as icase directory matches query
  • and also module load -i ICase command will load icase/1.2
    • as no directory ICase exists, result is returned from highest directory: icase