commands.revert: don't call hg.revert commands.revert calculates everything that has to be done and then calls hg.revert to checkout and remove files. Unfortunately, hg.revert has to recalculate everything and that can take a long while, since it always operates on the whole working dir. Changing commands.revert to manually checkout and remove files makes things considerably faster, especially if we're reverting a single file in a repo with a huge number of files. This should be enough to close issue857.