mariadb-migrator-troubleshooting

The MySQL-to-MariaDB migrator's known defects and failure playbook — the bash 3.2 traps (unbound SRC_SSL_ARGS, exit 143 without pv, declare -A in staged mode), the SHOW PACKAGE STATUS 1064 that is a mariadb-dump age problem and not a MySQL 8.4 one, the root-user and existing-target-DB refusals, option-file contamination, and what every refusal message from set_config/plan/run/resume means and what to set. Use when a migration was refused, a run failed or timed out, every step reported SKIPPED, or an error message from the migrator tools has to be diagnosed. Read mariadb-migrator first for the tools and preconditions.