Create a repository: $ hg config defaults.backout=-d "0 0" defaults.commit=-d "0 0" defaults.shelve=--date "0 0" defaults.tag=-d "0 0" devel.all-warnings=true largefiles.usercache=$TESTTMP/.cache/largefiles (glob) ui.slash=True ui.interactive=False ui.mergemarkers=detailed ui.promptecho=True $ hg init t $ cd t Make a changeset: $ echo a > a $ hg add a $ hg commit -m test This command is ancient: $ hg history changeset: 0:acb14030fe0a tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: test Verify that updating to revision 0 via commands.update() works properly $ cat < update_to_rev0.py > from mercurial import ui, hg, commands > myui = ui.ui() > repo = hg.repository(myui, path='.') > commands.update(myui, repo, rev=0) > EOF $ hg up null 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ python ./update_to_rev0.py 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg identify -n 0 Poke around at hashes: $ hg manifest --debug b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644 a $ hg cat a a Verify should succeed: $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 1 changesets, 1 total revisions At the end... $ cd ..