Component Licenses Gap

[jkrech]

Gaps:
Today: Single license ASCII file
Extensions:

• one or more licenses for one or multiple components
• click through optional
• spdx license reference
• display title for license file

Shadowfax Proposal:
Follow the approach already used for <conditions> in the current Pack Description
using references:

• add section <licenseSets> on the top level of the format
• add one or more child elements <licenseSet> to <licenseSets> with attributes:
  • id (required) - a unique name which is used by components to associate itself with a licenseSet
  • default (optional) - a single licenseSet can be declared as default="true". In this case all components that
    do not specify a licenseSet are implicitly associated with this default licenseSet. If the default attribute
    is not specified it defaults to false.
  • gating (optional) - licenseSet is selected for being displayed as part of click through license, gating
    the installation of a pack. If gating is not specified it defaults to false.
• add one or more child elements <license> to <licenseSet> with attributes:
  • name (required) - the file path and name of license file relative to pdsc file
  • title (required) - the displayed license title
  • spdx (optional) - a machine readable license ID string according to SPDX License List
• add optional attribute licenseSet to <component> element.
• add optional attribute licenseSet to <api> element.
• limit supported file formats for license files to ASCII files with no or .txt extension.

Consequences

• Complexity of package description increases
• the default mechanism allows to specify a single licenseSet for all components of a pack conveniently.
• For backward compatibility it is required to continue supporting <license> tag on top level. <license> vs.
  <licenseSet> shall be used mutually exclusively.
• Validation tool is required to test:
  • for each <license> that name is specified and file exists
  • for each <license> that the SPDX identifier is valid
  • for all licenseSet to have a unique ID (within pdsc)
  • a maximum of one licenseSet has attribute default="true" set
  • for each <component> that attribute licenseSet unique ID exists (within pdsc)
  • for each <api> that attribute licenseSet unique ID exists (within pdsc)
• Pack Installer requires extensions
  • display more than one license for "click through"
  • display license title
  • display SPDX information (e.g. with a link) if attribute is given
• Pack Manager requires extension
  • display license information per component