Package Exclusion

Introduction

This page describes some proposed updates to the INCOMPATIBLE_LICENSE and COMMERCIAL* package exclusion mechanisms within Poky for the Yocto Project version 1.1.

Aims

• Make error messages clear when user/dependencies have asked for something to be built that can't be due to restrictions
• Ensure that exclusion system is reliable

Proposed implementation

1. Ensure all documentation of LICENSE field value syntax is clear, concise and up-to-date (wiki and manual)
2. Go through and audit all recipes LICENSE field values to ensure that they all conform to the specifications. This includes making sure that | (package may be used under one of a selection of licences) and & (recipe has mixed licences that apply to the code base, so conditions of all must be observed) are used correctly.
3. bitbake/core changes:
   • LICENSE field checking must fully parse the field and understand the difference between | and &, and must not e.g. mark Qt as being GPLv3 only.
   • Make the LICENSE validity checking more strict (given recipes have been audited and rules are clear after above)
   • Don't exclude any recipes at parse time - simply record all excluded recipes and their runtime provides in a blacklist which also includes flags indicating the reason for blacklisting
   • Ensure all excluded licences in INCOMPATIBLE_LICENSE are valid (e.g. catch GPL3 as apposed to GPLv3) - if not, error out
   • Check when calculating dependencies if anything is scheduled to be built that is on the blacklist - if any are, gather all of them up and then stop and list them in an error message along with reason and depchain for each one
   • Check when constructing the rootfs if anything in the runtime provides blacklist is going to be included - if so, error out

Some further possible extensions:

• Possibly apply similar logic to COMPATIBLE_MACHINE?
• Replace COMMERCIAL* with some more generic exclusion mechanism that allows the reason to be defined as part of the exclusion list?
• As a helper for non-en_US users, fail on parse if user defines any of the *LICENSE* variables as *LICENCE*? (we definitely don't want the build to continue and just ignore this as the user might not realise what has happened)