*: Add UPDATING entry of the Python 3.7 to 3.8 switchover

Add appropriately adapted upgrading instructions that have resulted
from the experience gained from the previous (Python 3.6 to 3.7)
switchover.

PR:		253815

1 files changed, 27 insertions, 0 deletions

diff --git a/UPDATING b/UPDATING
index fef2c4531fc9..0c71f8ff8024 100644
--- a/UPDATING
+++ b/UPDATING
@@ -5,6 +5,33 @@ they are unavoidable.
 You should get into the habit of checking this file for changes each time
 you update your ports collection, before attempting any port upgrades.
 
+20210425:
+  AFFECTS: users of python
+  AUTHOR: kai@FreeBSD.org
+
+  The default version of python3 and python was switched to 3.8.
+
+  For ports users wanting to keep version 3.7 as default,
+  add DEFAULT_VERSIONS+= python=3.7 python3=3.7 to make.conf
+
+  Following procedures may ease the upgrade:
+
+  For users of pre-build packages:
+  # sh
+  # for i in $(pkg query -g %n 'py37-*'); do pkg set -yn ${i}:py38-${i#py37-}; done
+  # pkg upgrade
+
+  For portmaster users:
+  # sh
+  # portmaster -o lang/python38 python37
+  # REINSTALL="$(pkg info -o py37-\* | awk '{printf "%s ", $2}')"
+  # pkg delete -f py37-\*
+  # portmaster $REINSTALL
+  # REBUILD=$(pkg query -g "%n:%dn" '*' | grep py3 | grep -v py38 | cut -d : -f 1 | sort -u)
+  # portmaster $REBUILD
+  # REBUILD2=$(pkg list | grep python-37 | xargs pkg which | awk '{print $6}' | sort -u)
+  # portmaster $REBUILD2
+
 20210420:
   AFFECTS: users of www/node
   AUTHOR: bhughes@FreeBSD.org