tests/helpers-testrepo.sh

obsolete: skip 'changectx' usage in unstable computation

We simplify the unstable computation code, skipping the expensive creation of
changectx object. We focus on efficient set operation and revnumber centric
functions.

In my mercurial development repository, this provides a 3x speedup to the
function:

  before: 5.319 ms
  after:  1.844 ms

repo details:

  total changesets:       40886
  obsolete changesets:     7756
  mutable (not obsolete):   293
  unstable:                  30

# Invoke the system hg installation (rather than the local hg version being
# tested).
#
# We want to use the hg version being tested when interacting with the test
# repository, and the system hg when interacting with the mercurial source code
# repository.
#
# The mercurial source repository was typically orignally cloned with the
# system mercurial installation, and may require extensions or settings from
# the system installation.
syshg () {
    (
        syshgenv
        exec hg "$@"
    )
}

# Revert the environment so that running "hg" runs the system hg
# rather than the test hg installation.
syshgenv () {
    . "$HGTEST_RESTOREENV"
    HGPLAIN=1
    export HGPLAIN
}

# Most test-check-* sourcing this file run "hg files", which is not available
# in ancient versions of hg. So we double check if "syshg files" works and
# fallback to hg bundled in the repo.
syshg files -h >/dev/null 2>/dev/null
if [ $? -ne 0 ]; then
    syshg() {
        hg "$@"
    }
    syshgenv() {
        :
    }
fi