tests: add tests of pathcopies() I'm working on support for storing copy metadata in the changeset instead of in the filelog. When storing it in the changeset, it will obviously be efficient to get the copy metadata for all files in a single changeset, but it will be more expensive to get the copy metadata all revisions of a single file. Some algorithms will then need to be optimized differently. The first method I'm going to rewrite is pathcopies(). This commit adds many tests for pathcopies(), so we can run the tests with both old and new versions of the code, as well as with metadata stored in filelog or in changeset (later). They use the debugpathcopies command I recently added (with no tests when it was added). They show a few bugs and few cases of slightly weird behavior. I'll fix the bugs in the next few commits. Differential Revision: https://phab.mercurial-scm.org/D5986

uncommit: add config option to keep commit by default We have a Google-internal extension that keeps track of "review units" (like Phabricator reviews, or Gerrit's Change-Id). This information is stored outside of the commit. It is updated with rewrites. Every now and then we get reports from users who are confused because `hg uncommit` lost track of their review. Keeping the empty commit by default would reduce this confusion. It may also cause confusion about the empty commit. This patch adds a config option that lets us easily test both behaviors on our users. Differential Revision: https://phab.mercurial-scm.org/D5970

debugpathcopies: sort output so it's deterministic Differential Revision: https://phab.mercurial-scm.org/D5983

subrepo: use root-repo-relative path from `hg files` with ui.relative-paths=no The fix is to pass in a "subuipathfn" as we do everywhere else. Differential Revision: https://phab.mercurial-scm.org/D5978

subrepo: demonstrate broken `hg files` with ui.relative-paths=no Differential Revision: https://phab.mercurial-scm.org/D5977

py3: whitelist 5 new passing tests caught by buildbot Thanks to indygreg and durin42 recent patches. Differential Revision: https://phab.mercurial-scm.org/D5979

uncommit: inform user if the commit is empty after uncommit Differential Revision: https://phab.mercurial-scm.org/D5969