compat: add a fixed version of mergecopies for hg<=4.3
In hg<=4.3, copies._fullcopytracing() does not exist and we have to wrap
copies.mergecopies() to fix the AssertionError coming from core.
#!/bin/bash
set -euox pipefail
unset GREP_OPTIONS
NOTOPIC="--config experimental.topic-mode=ignore"
compatbranches=`hg branches --quiet | grep 'mercurial-' | grep -v ':' | sort -n --reverse`
prev='stable'
for branch in $compatbranches; do
hg up $branch
hg merge $prev
hg commit -m "test-compat: merge $prev into $branch"
prev=$branch
done