diff options
Diffstat (limited to '_sources/other-metadata.rst.txt')
| -rw-r--r-- | _sources/other-metadata.rst.txt | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/_sources/other-metadata.rst.txt b/_sources/other-metadata.rst.txt new file mode 100644 index 0000000..ca3759a --- /dev/null +++ b/_sources/other-metadata.rst.txt @@ -0,0 +1,39 @@ +Other metadata variables +======================== + +.. index:: slot/subslot; dynamic +.. index:: USE flags; multislot + +Dynamic slots (multislot flag) +------------------------------ +:Source: QA (inferred from PMS) +:Reference: https://wiki.gentoo.org/index.php?title=Project:Quality_Assurance/Policies&oldid=109991#multislot.2FUSE-dependent_SLOT +:Reported: ``use`` in global scope triggers fatal error + +The use of ``multislot`` to alter ``SLOT`` values (as well as any other +USE-dependent slot values) in the Gentoo repository is forbidden. +Such a feature can be used in overlays, and it is acceptable to provide +such support in eclasses as long as it is not used in ::gentoo. + +This policy has been explicitly declared in response to historical +(pre-2016) use of ``USE=multislot`` in toolchain ebuilds. When the flag +was disabled, all package versions used the same slot, and upgrades were +handled as for non-slotted packages. When the flag was enabled, each +version used a separate slot, permitting multiple versions being +installed simultaneously. This allowed the user to choose between +the two options. + +The original violation has been resolved by unconditionally slotting +the packages. This permitted the users to install multiple versions +in parallel, while removal of old versions was to be handled via +``emerge --depclean``. + +*Rationale*: this feature was in direct violation of PMS `metadata +invariance`_ requirements. It caused the cached slot value to depend +on the state of querying the USE flag (which in turn could technically +depend on slot, via ``package.use``). This caused undefined package +manager behavior which could include use of unpredictable slot, cache +invalidation or explicit errors. + + +.. _metadata invariance: https://projects.gentoo.org/pms/7/pms.html#x1-600007.1 |