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| -rw-r--r-- | 2021-01-30-python-preference-to-follow-PYTHON-TARGETS/2021-01-30-python-preference-to-follow-PYTHON-TARGETS.en.txt | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/2021-01-30-python-preference-to-follow-PYTHON-TARGETS/2021-01-30-python-preference-to-follow-PYTHON-TARGETS.en.txt b/2021-01-30-python-preference-to-follow-PYTHON-TARGETS/2021-01-30-python-preference-to-follow-PYTHON-TARGETS.en.txt new file mode 100644 index 0000000..dbdf2a7 --- /dev/null +++ b/2021-01-30-python-preference-to-follow-PYTHON-TARGETS/2021-01-30-python-preference-to-follow-PYTHON-TARGETS.en.txt @@ -0,0 +1,48 @@ +Title: Python preference to follow PYTHON_TARGETS +Author: Michał Górny <mgorny@gentoo.org> +Posted: 2021-01-30 +Revision: 1 +News-Item-Format: 2.0 + +On 2021-02-01 stable users will switch to a new method of updating +the preferred Python versions that employs the configuration update +mechanism in order to follow PYTHON_TARGETS. We will also deprecate +app-eselect/eselect-python, and it will stop being installed by default +after 2021-07-01. If you wish to use the newest Python version present +in your PYTHON_TARGETS, you only have to accept configuration changes. +If you wish to customize the behavior, read on. + +Since 2017, /usr/bin/python and the related non-versioned symlinks +are wrapped through dev-lang/python-exec. The list of preferred Python +implementations is stored in /etc/python-exec/python-exec.conf and/or +per-program /etc/python-exec/<basename>.conf configuration files. +To preserve backwards compatibility, app-eselect/eselect-python remained +a wrapper that updated this file. + +However, this mechanism alone has proven inconvenient to end users who +had to update python-exec.conf whenever the default PYTHON_TARGETS +changed. Thanks to the fallback logic, this was not a major problem +for software installed via Gentoo packages that always ensure that +a supported implementation is used. However, users have reported that +whenever the preference for /usr/bin/python mismatched their +PYTHON_TARGETS, their custom scripts would break due to unsatisfied +dependencies. This does not follow the principle of least surprise. + +For this reason, we have decided to change the default python-exec +configuration to match PYTHON_TARGETS by default, in the eclass +preference order, that is from the newest CPython version to oldest, +with alternative Python implementations coming afterwards. This change +will be propagated via the configuration protection mechanism whenever +dev-lang/python-exec-conf is installed or rebuilt due to PYTHON_TARGETS +changes. This will permit the users to interactively confirm +the updates. + +If the new default is not correct for you, please use your preferred +configuration update tool to discard or edit the new configuration file. + +Furthermore, dev-lang/python will no longer attempt to automatically +update the Python interpreter preference, or pull in eselect-python +automatically. If you wish to continue using it, please install/record +it explicitly to ensure that it is not unmerged, e.g.: + + emerge -n app-eselect/eselect-python |